Australian ravens begin breeding once they are three years old. Breeding season is from July to September, with no substantial difference in timing across its range around the country despite it inhabiting a range of diverse climates and habitats across 19 degrees of latitude. Rowley has pointed out this is unusual for a bird species with a wide range and has postulated that breeding is initiated by day length. Rarely, breeding can take place in May, June or October. Australian ravens generally nest in tall trees, never near to the ground as some species do. The nest also functions as a lookout post and so tall or emergent trees are selected. The ravens occasionally nest on buildings, telegraph poles, or tall windmills which allow the species to occupy areas lacking in tall trees. Windmills may have assisted the spread of the species in North Queensland and the Northern Territory. The highest recorded corvid nest in Australia was found atop the AWA Tower in Sydney.
Nests are generally large and untidy, consisting of a bowl or platform of sticks lined with grasses, barks, and feathers that can be up to 5 cm (2.0 in) thick. As they are relatively heavy, they are built on larger forks in trees rather than out in the canopy. Building the nest is often time-consuming initially as the birds try (and often fail) to wedge sticks, which are 30–60 cm (12–24 in) long and 0.6–1.2 cm (1⁄4–1⁄2 in) thick, into the tree fork to make a platform. Thinner sticks and rootlets are used to make the bowl before the bowl is lined with feathers. Both birds build the nest, with the female taking over the lining of the nest while the male brings her material. New nests are built each year generally, as the re-use of old ones might spread disease or parasites—nests become caked with faeces as the nestlings grow and the parents cannot keep up with its removal. Furthermore, old nests often disintegrate within twelve months due to their exposed locations. The female develops a brood patch—a patch of bare skin on the bird's underparts that reddens and becomes much more extensive from around three weeks before the first egg is laid. The skin itself is oedematous and wrinkled, and does not get re-feathered until December after the breeding season has finished.
Their lofty locations makes monitoring of Australian raven nests difficult. A clutch can comprise up to six eggs, though usually four or five are laid, with five being the most common number. Measuring 45 by 30 mm (1+3⁄4 by 1+1⁄4 in), eggs are pale green or bluish-green and splotched with darker olive, brown and blackish markings. Eggs are quite variable, and thus which Australian corvid laid them cannot be reliably identified. Incubation of the eggs is done solely by the female over roughly 20 days. Incubation is intermittent initially, becoming constant by the time the third or fourth egg is laid. Only one brood is raised per year, though a second clutch may be laid if the first clutch is lost early in the season. Late clutches have poor survival rates, possibly due to chicks getting dehydrated on hot days as the year progresses or being eaten by wedge-tailed eagles. The chicks are altricial and nidicolous; that is, they are born helpless, naked and blind, and remain in the nest for an extended period. They have pink skin until 5 days of age, when feathers under the skin turn it grey. They lose their egg tooth at the same time. Their eyes begin opening at 5 to 6 days of age and are fully open by 11 to 12 days, by which time their feathers begin emerging. At 14 days, their primary feathers begin emerging, and they are fully feathered by 35–36 days old. They leave the nest at 40–45 days of age, and stay with the parents for three to four months after that. They follow their parents and beg for food for the first month outside the nest but are feeding themselves by the third month. Young birds are often attacked when they enter neighbouring territories, and melees ensue as their parents try to defend them and herd them back.


The Australian raven is omnivorous, though eats more meat than smaller corvids. Its diet in summer contains a high proportion of insects, while more plant items are eaten in autumn. Flesh makes up over half its diet in winter. Invertebrates commonly eaten include spiders, millipedes, centipedes (which ravens behead before eating), grasshoppers, cicadas and caterpillars (especially of the family Noctuidae), which are important in feeding nestlings. Australian ravens sometimes eat yabbies (Cherax destructor) from the edges of dams. Unusually for a ground-feeding omnivore, earthworms are rarely eaten. Australian ravens have been reported killing birds of such size as young galahs (Eolophus roseicapillus) and starlings (Sturnus vulgaris). Most mammals are eaten as carrion, as many species are too large for the raven to kill, though young rabbits are a frequent prey item. Australian ravens drink water frequently, up to ten times a day in hot weather. Birds have been observed dunking pieces of meat in water before eating them, as well as doing the same with hard biscuits to make them soggy and soft.
Australian ravens are intelligent birds, and like many other corvids have innovative methods of seeking out food. Foraging takes place in the early morning or late afternoon; birds rest in the hotter part of the day. Food is taken mainly from the ground, birds either finding objects while flying overhead or by walking along and looking. However, they occasionally feed in trees—Australian ravens forage eucalypt foliage for Christmas beetles (Anoplognathus), and devote a substantial amount of time to look for nests and eggs to eat. They have also been known to take golf balls from fairways, possibly mistaking them for eggs. Ravens use their bill rather than their feet to explore or turn items on the ground (rocks or sticks) over or hold or snatch food while flying. They have also been recorded using fence posts as anvils to bash snails against before eating them. Australian ravens most often eat food where they find it unless taking food back for nestlings. Occasionally they have been observed caching carrion or a killed animal in a hole nearby to store it. They can pack shredded meat in their mouth under their tongue. Australian ravens have adapted well to eating food scraps in urban areas, such as school playgrounds, rubbish tips, bins outside supermarkets or restaurants, abattoirs, piggeries and farmyards. In one isolated study, they were observed feeding on nectar from eucalypt flowers. Australian ravens sometimes forage in mixed-species flocks with any of the other four species of Australian corvids. Sometimes they are aggressive with little ravens if both are at a food source and drive them off, though not if the smaller species greatly outnumber the larger.


A circovirus—given the name raven circovirus or RaCV—was isolated from an Australian raven suffering from feather lesions in 2006. It has affinities with canary circovirus (CaCV) and pigeon circovirus (PiCV). Its clinical significance is unknown. A species of Isospora—given the name of I. coronoideae was isolated from this species, its only known host. Tick infestation is rare in the Australian raven, with Ixodes holocyclus and Amblyomma triguttatum recorded. Lice and hippoboscid flies have been recorded yet little-researched, and an infestation by the fly Passeromyia longicornis was recorded in one nest.
The wedge-tailed eagle (Aquila audax) preys on adult, nestling, and fledgling Australian ravens, while the little eagle (Hieraaetus morphnoides) also takes nestlings, and powerful owl (Ninox strenua) has been recorded killing adults; other birds of prey are seen as threats, yet there is no evidence they have successfully preyed on the ravens. The introduced red fox (Vulpes vulpes) competes with the Australian raven for carrion and can drive it off. It may also kill young birds that it catches on the ground. The channel-billed cuckoo (Scythrops novaehollandiae) has been recorded as a brood parasite.


Australian ravens sometimes die by being shot or poisoned—generally by farmers. Despite their fondness for roadkill, fewer ravens are hit by vehicles than Australian magpies. Research in the 1950s and 60s showed that 64% of Australian ravens perished in their first year of life. Immature birds are most at risk of dying. The Australian raven is a peaceful bird, showing no aggression toward humans or other birds without reason. However, the Australian raven is frequently blamed for the loss of young lambs. Scientific observation in the country's southeast showed that the killing of healthy lambs was rare, but that sick animals were predisposed to being attacked. Australian ravens mostly eat faeces (often from the lamb's anus), afterbirth or stillborn lambs. Newborn lamb faeces is nutritious, containing around 21–44% protein, 9–37% fat and 10–30% carbohydrate. It has the consistency of treacle and often sticks to the lamb's hindquarters or tail. The raven bites a sleeping lamb's tail, holding on and walking behind it when it wakes up. A healthy lamb would respond by running away or butting the bird, but a sick one might not respond and be attacked further as it alerts the bird that it is vulnerable. Wounded lambs can also succumb to Clostridium infection as these bacteria are present on raven bills. Ravens bring some benefits to agricultural areas as they clean away carrion and eat insects that are potentially damaging to crops. In areas of Western Australia, the species is classified as a Declared Pest of Agriculture under the provisions of the Agriculture and Related Resources Protection Act 1976, meaning that shooting on private land in rural areas is legal, although should be considered only after other options have been exhausted.


In Australian Aboriginal mythology, Crow is a trickster, culture hero and ancestral being. In the Kulin nation in central Victoria he was known as Waa (also Wahn or Waang) and was regarded as one of two moiety ancestors, the other being the more sombre eaglehawk Bunjil. Legends relating to Crow have been observed in various Aboriginal language groups and cultures across Australia.
To the Noongar people of southwestern Australia, the Australian raven was Waardar, "the Watcher" and was wily and unpredictable. Noongar people were socially divided into two moieties or kinships: waardarng-maat and marrnetj-maat, or members of the Australian raven and long-billed corella (Cacatua tenuirostris) respectively.


John Latham had described the south-seas raven in 1781, with loose throat feathers and being found in "the Friendly Isles" in the South Seas, but did not give it a binomial name. The place is thought to be Tonga. Gmelin gave it the name Corvus australis in the 13th edition of Systema naturae in 1788.
Rowley and colleagues recorded iris colour changes of all five Australian corvid species raised in captivity.
Lambing takes place in late winter, with stillbirth rates around 20%, so there is a supply of carrion around farming areas.


The rook was given its binomial name by the Swedish naturalist Carl Linnaeus in 1758 in his Systema Naturae. The binomial is from Latin; Corvus means "raven", and frugilegus means for "fruit-gathering". It is derived from frux or frugis, meaning "fruit", and  legere, meaning "to pick". The English-language common name rook is ultimately derived from the bird's harsh call. Two subspecies are recognised; the western rook (C. f. frugilegus) ranges from western Europe to southern Russia and extreme northwestern China, while the eastern rook (C. f. pastinator) ranges from central Siberia and northern Mongolia eastwards across the rest of Asia. Collective nouns for rooks include building, parliament, clamour and storytelling. Their colonial nesting behaviour gave rise to the term rookery.


The rook is a fairly large bird, at 280 to 340 g (9.9 to 12.0 oz) adult weight, 44 to 46 cm (17 to 18 in) in length and 81 to 99 cm (32 to 39 in) wingspan. It has black feathers that often show a blue or bluish-purple sheen in bright sunlight. The feathers on the head, neck and shoulders are particularly dense and silky. The legs and feet are generally black, the bill grey-black and the iris dark brown. In adults, a bare area of whitish skin in front of the eye and around the base of the bill is distinctive, and enables the rook to be distinguished from other members of the crow family. This bare patch gives the false impression that the bill is longer than it is and the head more domed. The feathering around the legs also appears shaggier and laxer than the similarly sized carrion crow, the only other member of its genus with which the rook is likely to be confused.  Additionally, when seen in flight, the wings of a rook are proportionally longer and narrower than those of the carrion crow. The average lifespan is six years.
The juvenile plumage is black with a slight greenish gloss, except for the hind neck, back and underparts, which are brownish-black. The juvenile is superficially similar to a young crow because it lacks the bare patch at the base of the bill, but it has a thinner beak and loses the facial feathers after about six months.


Rooks are resident in the British Isles and much of north and central Europe but vagrant to Iceland and parts of Scandinavia, where they typically live south of 60° latitude. They are found in habitats that ravens dislike, choosing open agricultural areas with pasture or arable land, as long as there are suitable tall trees for breeding. They generally avoid forests, swamps, marshes, heaths and moorland. They are in general lowland birds, with most rookeries found below 120 m (400 ft), but where suitable feeding habitat exists, they may breed at 300 m (1,000 ft) or even higher. Rooks are often associated with human settlements, nesting near farms, villages and open towns, but not in large, heavily built-up areas.
The rook also occurs as an eastern species in Asia where it differs in being slightly smaller on average, and having a somewhat more fully feathered face. In the north of its range the species has a tendency to move south during autumn, and more southern populations are apt to range sporadically. The species has been introduced into New Zealand, with several hundred birds being released there from 1862 to 1874. Although their range is very localized, the species is now regarded as an invasive pest and is the subject of active control by many local councils. This has wiped out the larger breeding colonies in New Zealand, and the remaining small groups have become more wary.


Rooks are highly gregarious birds and are generally seen in flocks of various sizes. Males and females pair-bond for life and pairs stay together within flocks. In the evening, the birds often congregate at their rookery before moving off to their chosen communal roosting site. Flocks increase in size in autumn with different groups amalgamating and birds congregating at dusk before roosting, often in very large numbers and in the company of jackdaws. Roosting usually takes place in woodland or plantations, but a small minority of birds may continue to roost at their rookery all winter, and adult males may roost collectively somewhere nearby. The birds move off promptly in the morning, dispersing for distances of up to 10 km (6 mi).
Large groups of rooks (in breeding colonies or night roost sites) can contribute to changes in soil properties. The amount of ornithogenic material in these soils is very high.
Foraging mostly takes place on the ground, with the birds striding about, or occasionally hopping, and probing the soil with their powerful beaks. Flight is direct, with regular wingbeats and little gliding while in purposeful flight; in contrast, the birds may glide more extensively when wheeling about in leisure flight near the rookery. In the autumn, flocks sometimes perform spectacular aerial group flights, including synchronised movements and individual antics such as dives, tumbles and rolls.


Examination of stomach contents show that about 60% of the diet is vegetable matter and the rest is of animal origin. Vegetable foods include cereals, potatoes, roots, fruit, acorns, berries and seeds while the animal part is predominantly earthworms and insect larvae, which the bird finds by probing the ground with its strong bill. It also eats beetles, spiders, millipedes, slugs, snails, small mammals, small birds, their eggs and young, and occasionally carrion.
In urban sites, human food scraps are taken from rubbish dumps and streets, usually in the early hours or at dusk when it is relatively quiet. Like other corvids, rooks will sometimes favour sites with a high level of human interaction, and can often be found scavenging for food in tourist areas or pecking open garbage sacks. Rooks have even been trained to pick up litter in a theme park in France.


The male usually initiates courtship, on the ground or in a tree, by bowing several times to the female with drooping wings, at the same time cawing and fanning his tail. The female may respond by crouching down, arching her back and quivering her wings slightly, or she may take the initiative by lowering her head and wings and erecting her partially spread tail over her back. Further similar displays are often followed by begging behaviour by the female and by the male presenting her with food, before coition takes place on the nest. At this stage, nearby male rooks often mob or attack the mating pair, and in the ensuing struggle, any male that finds himself on top of the female will attempt to copulate with her. She terminates these unwanted advances by exiting the nest and perching nearby. A mated pair of rooks will often fondle each other's bills, and this behaviour is also sometimes seen in autumn.


Nesting in a rookery is always colonial, usually in the very tops of large trees, often on the remnants of the previous year's nest. In hilly regions, rooks may nest in smaller trees or bushes, and exceptionally on chimneys or church spires. Both sexes participate in nest-building, with the male finding most of the materials and the female putting them in place. The nest is cup-shaped and composed of sticks, consolidated with earth and lined with grasses, moss, roots, dead leaves and straw. Small branches and twigs are broken off trees, though as many are likely to be stolen from nearby nests as are collected direct, and the lining material is also often taken from other nests.
Eggs are usually three to five in number (sometimes six and occasionally seven) and may be laid by the end of March or early April in Britain, but in the harsher conditions of eastern Europe and Russia, it may be early May before the clutch is completed. The background colour is bluish-green to greyish-green but this is almost completely obscured by the heavy blotching of ashy grey and brown. The eggs average 40.0 by 28.3 millimetres (1.57 in × 1.11 in) in size. They are incubated for 16–18 days, almost entirely by the female who is fed by the male. After hatching, the male brings food to the nest while the female broods the young. After ten days, she joins the male in bringing food, which is carried in a throat pouch. The young are fledged by the 32nd or 33rd day but continue to be fed by the parents for some time thereafter. There is normally a single clutch each year, but there are records of birds attempting to breed in the autumn.
In autumn, the young birds of the summer collect into large flocks together with unpaired birds of previous seasons, often in company with jackdaws. It is during this time of year that spectacular aerial displays are performed by the birds. The species is monogamous, with the adults forming long-term pair bonds. Partners often support each other in agonistic encounters and a bird may return to its partner after a quarrel where bill twining, an affiliative behaviour, may take place.


The call is usually described as caw or kaah, and is somewhat similar to that of the carrion crow, but less raucous. It is variable in pitch and has several variants, used in different situations. The call is given both in flight and while perched, at which time the bird fans its tail and bows while making each caw. Calls in flight are usually given singly, in contrast to the carrion crow's, which are in groups of three or four. Other sounds are made around the rookery; a high-pitched squawk, a "burring" sound and a semi-chirruping call. Solitary birds occasionally "sing", apparently to themselves, uttering strange clicks, wheezes and human-like notes; the song has been described as a "base or guttural reproduction of the varied and spluttering song" of starlings.


Although outside of captivity rooks have not shown probable tool-use, captive rooks have shown the ability to use and understand puzzles. One of the most commonly tested puzzles is the Trap-Tube Problem. Rooks learned how to pull their reward out of the tube while avoiding a trap on one side.
In captivity, when confronted with problems, rooks have been documented as one of several species of birds capable of using tools as well as modifying tools to meet their needs. Rooks learned that if they push a stone off a ledge into a tube, they will get food. The rooks then discovered they could find and bring a stone and carry it to the tube if no stone was there already. They also used sticks and wire, and figured out how to bend a wire into a hook to reach an item. Rooks also understood the notion of water levels. When given stones and a tube full of water with a reward floating, they not only understood that they needed to use the stones but also the best stone to use.
In one set of experiments, rooks managed to knock a reward off a platform by rolling a stone down a tube toward the base of the platform. Rooks also seemed to understand the idea that a heavier stone will roll more quickly and be more likely to knock the platform over. In this same test, rooks showed they understood that they needed to pick a stone of a shape that would roll easily.
Rooks also show the ability to work together to receive a reward. In order to receive a reward, multiple rooks had to pull strings along the lid of a box in order for it to move and them to reach the reward. Rooks seem to have no preference regarding working as a group comparative to working singly.
They also seem to have a notion of gravity, comparable to a six-month-old baby and exceeding the abilities of chimpanzees. Although they do not use tools in the wild, research studies have demonstrated that rooks can do so in cognition tests where tools are required, and can rival, and in some circumstances outperform, chimpanzees.


Farmers have observed rooks in their fields and thought of them as vermin. After a series of poor harvests in the early 1500s, Henry VIII introduced a Vermin Act in 1532 "ordeyned to dystroye Choughes (i.e. jackdaws), Crowes and Rokes" to protect grain crops from their predations. This act was only enforced in piecemeal fashion, but Elizabeth I passed the Act for the Preservation of Grayne in 1566 that was taken up with more vigour and large numbers of birds were culled.
Francis Willughby mentions rooks in his Ornithology (1678): "These birds are noisome to corn and grain: so that the husbandmen are forced to employ children, with hooting and crackers, and rattles of metal, and, finally by throwing of stones, to scare them away." He also mentions scarecrows "placed up and down the fields, and dressed up in a country habit, which the birds taking for countrymen dare not come near the grounds where they stand". It was some time before more observant naturalists like John Jenner Weir and Thomas Pennant appreciated that in consuming ground-based pests, the rooks were doing more good than harm.
Rookeries were often perceived as nuisances in rural Britain, and it was previously the practice to hold rook shoots where the juvenile birds, known as "branchers", were shot before they were able to fly. These events were both a social occasion and a source of food (the rook becomes inedible once mature) as rook and rabbit pie was considered a delicacy.
Rooks have a wide distribution and large total population. The main threats they face are from changes in agricultural land use, the application of seed dressings and pesticides, and persecution through shooting. Although total numbers of birds may be declining slightly across the range, this is not at so rapid a rate as to cause concern, and the International Union for Conservation of Nature has assessed the bird's conservation status as being of "least concern".


The large-billed crow (Corvus macrorhynchos), formerly referred to widely as the jungle crow, is a widespread Asian species of crow. It is very adaptable and is able to survive on a wide range of food sources, making it capable of colonizing new areas, due to which it is often considered a nuisance, especially on islands. It has a large bill, which is the source of its scientific name macrorhynchos (Ancient Greek for "large beak") and it is sometimes known by the common name thick-billed crow. It can also be mistaken for a common raven. Johann Georg Wagler first described the species from a holotype obtained from Java in the year 1827. The eastern jungle crow and Indian jungle crow were once considered conspecific and together called the jungle crow.


It has nine subspecies, and some of them are distinctive vocally, morphologically and genetically, leading to treatments that raise some of them into species status.
C. m. colonorum
C. m. connectens
C. m. intermedius
C. m. japonensis
C. m. macrorhynchos
C. m. mandschuricus
C. m. osai
C. m. philippinus
C. m. tibetosinensis


The range of this species is extensive and stretches from the northeastern Asian seaboard to Afghanistan and eastern Iran in the west, through South and Southeast Asia, to the Lesser Sundas and  Cambodia in the southeast. It occurs in woodland, parks and gardens, cultivated regions with at least some trees, but is a bird of more open country in the south of its range where it is not in competition with the common raven and carrion crow of the north.


Extremely versatile in its feeding, it will take food from the ground or in trees. They feed on a wide range of items and will attempt to feed on anything appearing edible, alive or dead, plant or animal. It is also one of the most persistent species and is quite bold, especially in urban areas. In Japan, crows are considered to be a pest, as they rip open garbage bags and take wire coat hangers for their nests. In Sri Lanka, Karunarathna & Amarasinghe (2008) noted that the jungle crow might actually be a, if not the, major predator of local small animals; jungle crows are highly experienced at catching lizards, taking only 45 minutes to find, catch and consume four critically endangered endemic lizards in Horton Plains National Park.
Food caching behaviour has been noted in ssp. culminatus.


The nest is a platform of twigs, usually high up on a tree with a preference for tall conifers like fir or pine. There are normally 3-5 eggs laid and they are incubated for 17–19 days. The young are fledged usually by about the 35th day. In India, the large-billed crow breed from March to May, but in the plains some of them start even in mid December. The nest is built in a fork of a tree, and is a shallow cup of sticks, sometimes neat and well made, sometimes sketchy and ragged; it is lined with grass roots, wool, rags, vegetable fibre, and similar materials. Some nests have been found to be built partly or exclusively of wire.
The normal clutch consists of four or five eggs, and rarely six or seven. The egg is a broad oval, rather pointed at the smaller end. The texture is hard and fine and there is a fair gloss. The ground colour is any shade of blue-green, and is blotched, speckled and streaked with dull reddish-brown, pale sepia, grey and neutral tint. In size the eggs average about 1.45 by 1.05 inches. The jungle crow can serve as a host for the Asian koel.


Gregarious at roosts with many thousands at some roost sites. Large flocks may be seen at dusk arriving at major roost sites. These roosts show no apparent reduction even during the breeding season, and this is because they do not breed during their first year. During the day pairs may be involved in defending their territory but at night they may roost in large groups. They have linear dominance hierarchies that are remembered based on individual recognition.


The voice is similar to the house crow to which it is closest, but deeper and usually more resonant and described as the usual loud "caa-haa-caa". However, it makes a range of calls, some which could be described as "cau cau" and others that could be mistaken for a woodpecker drumming.


There are few predators of this species. Filarial parasites have been reported from this species. Pathogenic viruses such as H5N1 have been noted to cause mortality in Japan. Large scale deaths have also been noted to be caused by Clostridium infection and enteritis.


The species are the western jackdaw (Corvus monedula), which breeds in the British Isles and western Europe, Scandinavia, northern Asia and Northern Africa, and its eastern counterpart, the Daurian jackdaw (Corvus dauuricus), found from China and eastern Siberia to Japan. The eastern species is smaller than the western jackdaw, and in eastern adults the pale areas of the plumage are almost white, whereas in the western bird these areas are pale grey. The iris is pale in western jackdaw and dark in Daurian jackdaw. The two species are otherwise very similar in shape, calls, and behaviour. There is an argument for lumping the subgenus members as one species, but they do not interbreed where their ranges meet in Mongolia.


The fish crow (Corvus ossifragus) is a species of crow associated with wetland habitats in the eastern and southeastern United States.


The fish crow was given its binomial name by the Scottish ornithologist Alexander Wilson in 1812, in the fifth volume of his American Ornithology. The binomial is from Latin; Corvus means "raven", while ossifragus means "bone-breaker". It is derived from os or ossis, meaning "bone", and frangere, meaning "to break". The English-language common name fish crow also derives from Wilson, who ascribed the name to the crow's aquatic diet, as described to him by local fishermen. He distinguished the fish crow from John Bartram's great seaside crow by the former's diminutive size when compared to the American crow.
The fish crow's taxonomic relation to other species of the Corvus genus is still poorly understood, but DNA sequencing indicates that it is most closely related to the palm crow (C. palmarum) and the Jamaican crow (C. jamaicensis), with the three species forming a Nearctic clade. The Sinaloa crow (C. sinaloae) and Tamaulipas crow (C. imparatus) bear morphological similarities to and were once considered conspecific subspecies of the fish crow, but have since been recognized as distinct species.


The fish crow is a small bird, with an average adult weight of 280–320 grams (9.9–11.3 oz) in males and 247–293 grams (8.7–10.3 oz) in females. The average male wingspan is similarly larger at 278–292 millimetres (10.9–11.5 in), compared to 264–277 millimetres (10.4–10.9 in) in females. The total body length is between 36–40 centimetres (14–16 in).
The fish crow is superficially similar to the American crow, but is smaller and has a silkier, smoother plumage by comparison. The upperparts have a blue or blue-green sheen, while the underparts have a more greenish tint to the black. The eyes are dark brown. The differences are often only really apparent between the two species when seen side by side or when heard calling. The bill is usually somewhat slimmer than the American crow, but is only readily distinguishable if both species are seen together.
Visual differentiation from the American crow is extremely difficult and often inaccurate. Nonetheless, differences apart from size do exist. Fish crows tend to have more slender bills and feet. There may also be a small sharp hook at the end of the upper bill. Fish crows also appear as if they have shorter legs when walking. More dramatically, when calling, fish crows tend to hunch and fluff their throat feathers.
The voice is the most outwardly differing characteristic for this species and other American crow species. The call of the fish crow has been described as a nasal "ark-ark-ark" or a begging "waw-waw". Birders often distinguish the two species (in areas where their range overlaps) with the mnemonic aid "Just ask him if he is an American crow. If he says "no", he is a fish crow." referring to the fact that the most common call of the American crow is a distinct "caw caw", while that of the fish crow is a nasal "nyuh unh". The fish crow also has a single call sounding like "cahrrr".


This species occurs on the eastern seaboard of the United States from Rhode Island south to Key West, and west along the northern coastline of the Gulf of Mexico and follows many river systems inland for quite some distance. Coastal marshes and beaches, rivers, inland lakes and marshes, river banks, and the land immediately surrounding all are frequented.


Food is taken mainly from the ground or shallow water where the bird hovers and plucks food items out of the water with its feet. The fish crow is omnivorous. It feeds on small crustaceans, such as crabs and shrimps, other invertebrates, stranded fish, and live fish if the situation favors their capture, eggs and nestlings of birds, small reptiles, the fruits of many trees, peanuts, and grains, as well as human scraps where available.


The nest is usually built high in a tree and is often accompanied in nearby trees with other nests of the same species forming small, loose colonies. Usually, four or five eggs are laid. Pale blue-green in colour, they bear blotches of olive-brown. Fish crows build a new nest for each breeding attempt. A pair of fish crows were reported to have raised a young blue jay for multiple weeks.


This species appears to be somewhat more resistant to West Nile virus than the American crow. Survival rates of up to 45% have been reported for fish crows, compared with near zero for American crows.


The house crow (Corvus splendens), also known as the Indian, greynecked, Ceylon or Colombo crow, is a common bird of the crow family that is of Asian origin but now found in many parts of the world, where they arrived assisted by shipping. It is between the jackdaw and the carrion crow in size (40 cm (16 in) in length) but is slimmer than either. The forehead, crown, throat and upper breast are a richly glossed black, whilst the neck and breast are a lighter grey-brown in colour. The wings, tail and legs are black. There are regional variations in the thickness of the bill and the depth of colour in areas of the plumage.


The nominate race C. s. splendens is found in Pakistan, India, Nepal and Bangladesh and has a grey neck collar. The subspecies C. s. zugmayeri is found in the dry parts of South Asia and Iran and has a very pale neck collar. The subspecies C. s. protegatus is found in southern India, the Maldives (sometimes separated as maledivicus) and Sri Lanka and is darker grey. C. s. insolens, found in Myanmar, is the darkest form and lacks the grey collar.


It has a widespread distribution in southern Asia, being native to Nepal, Bangladesh, India, Pakistan, Sri Lanka, Maldives and Laccadive Islands, South West Thailand and coastal southern Iran. It was introduced to East Africa around Zanzibar (about 1897) and Port Sudan. It arrived in Australia via ship but has up to now been exterminated. Recently, it has made its arrival in Europe and has been breeding in the Dutch harbour town Hook of Holland since 1998.
A population between 200 and 400 birds has been present in Sham Shui Po, New Kowloon, Hong Kong, in particular Lai Kok Estate and Sham Shui Po Park, as well as Kowloon Tsai Park in Kowloon Tsai. An individual has been present in Cork Harbour on the south coast of Ireland since early September 2010.
In the New World, a small population of house crows is established in the area around St. Petersburg, Florida.
It is associated with human settlements throughout its range, from small villages to large cities. In Singapore, there was a density of 190 birds/km² in 2001 with efforts to suppress the population in planning.
Due to a human population explosion in the areas it inhabits, this species has also proportionately multiplied. Being an omnivorous scavenger has enabled it to thrive in such circumstances.


The invasive potential for the species is great all over the tropics. This species is able to make use of resources with great flexibility and appears to be associated with humans, and no populations are known to exist independently of humans. Based on niche-modelling it is estimated that it can also persist in some coastal areas in southern and northwestern Europe. In 2016, house crow was added to the List of Invasive Alien Species of Union concern. Breeding population of this species is reported from Netherlands (Hoek van Holland), while individuals were seen in Belgium, Hungary, Poland and Spain.


House crows feed largely on refuse around human habitations, small reptiles and mammals, and other animals such as insects and other small invertebrates, eggs, nestlings, grain and fruits. House crows have also been observed swooping down from the air and snatching baby squirrels. Most food is taken from the ground, but also from trees as opportunity arises. They are highly opportunistic birds and given their omnivorous diet, they can survive on nearly anything that is edible. These birds can be seen near marketplaces and garbage dumps, foraging for scraps. They have also been observed to eat sand after feeding on carcasses.


It is suspected that paramyxoviruses, such as PMV 1 that causes of Newcastle disease may be spread by Corvus splendens. Outbreaks of Newcastle disease in India were often preceded by mortality in crows. They have also been found to carry Cryptococcus neoformans, which can cause cryptococcosis in humans.
House crows in Tanzania curiously showed an absence of blood parasites, although some species such as Trypanosoma corvi have been first described from this species. Pathologist T.R. Lewis expressed surprise at the numbers of haematozoa present in the blood of house crows from Calcutta.


Corydalis cava is a species of flowering plant in the family Papaveraceae, native to moist, shady, woodland habitats throughout most of mainland Europe, although commonest in central and southeast Europe.
Its range extends from Spain in the west to Ukraine, Belarus and the Caucasus in the east and as far north as Sweden. It is absent from (though may sometimes be found in a naturalised state in) Iceland, the UK, the Netherlands, Norway, Finland, Russia and Greece.


Corydalis cava grows 15 cm (6 in) to 30 cm (12 in) tall. It is a spring ephemeral—foliage that grows in the spring dies down to its tuberous rootstock in summer. It has long-spurred flowers which appear in spring. The flowers may be mauve, purple, red, or white.
The seeds contain an elaiosome that attracts ants, which transport the seeds into their ant colony. This seed transportation is called myrmecochory.


Many of the species in Corydalis contain alkaloids such as canadine and corydaline, which blocks calcium. The majority of these belong to the isoquinoline alkaloid group. All parts of the plant are alkaloidal but the highest concentrations are present in the hollow root tuber.
Corydalis cava and some other tuberous species contain the alkaloid bulbocapnine, which is occasionally used in medicine but for which scientific evidence is lacking in regard to correct dosage and side effects.


The eastern dobsonfly, Corydalus cornutus, is a large insect in the Corydalidae family. It is found in eastern North America in regions with fast-flowing streams where its aquatic larvae develop. These are known as hellgrammites and are among the top invertebrate predators in the streams in which they live. They are used by anglers as bait.


The dobsonfly is found in most of eastern North America. It is usually found near the swift flowing, unpolluted streams in which its larvae develop.


The eggs are grey and cylindrical, about 1.4 millimetres long and 0.5 millimetres wide. They are laid in groups of about 1,000, stacked in three layers. The pile of eggs is protected by a clear fluid which dries white and is applied by the female with the tip of her abdomen. The egg mass is said to look rather like a bird dropping.
The larvae are light brown with a covering of tiny dark brown microspines. The thorax has three pairs of legs and each segment is covered by a tough, dark-coloured dorsal plate. The first eight abdominal segments have lateral tactile filaments and the first seven have tracheal gills in tufts. The larvae also have spiracles allowing them to breathe on land as well as in the water. At the tip of the abdomen there are two prolegs, each with a dorsal filament and a pair of terminal hooks which enables the larva to anchor itself in fast-flowing water. The mandibles are sclerotised and powerful.
The pupae are orange in colour with dark patches on the upper side of the abdomen and are covered with minute bristles. The developing limbs, wings and antennae project outside the pupal covering.
The adult dobsonfly is a large insect up to 140 millimetres long with a wingspan of up to 125 millimetres. The female has short powerful mandibles of a similar size to those of the larva while the mandibles of the male are sickle-shaped and up to 40 millimetres long, half as long as the body. The antennae are long and segmented and the greyish translucent, many veined wings are often mottled with white dots. When at rest the wings are folded flat over the insect's back and extend beyond the abdomen.


Corylus americana, the American hazelnut or American hazel, is a species of deciduous shrub in the genus Corylus, native to the eastern and central United States and extreme southern parts of eastern and central Canada.


The American hazelnut grows to a height of roughly 2.5 to 5 m (8 to 16 ft),  with a crown spread of 3 to 4.5 m (10 to 15 ft). It is a medium to large shrub, which under some conditions can take the like of a small tree. It is often multi-stemmed with long outward growing branches that form a dense spreading or spherical shape. It spreads by sending up suckers from underground rhizomes 10 to 15 cm (4 to 6 in) below the surface.
It blooms in very early to mid spring, producing hanging male (staminate) catkins 4 to 8 cm (1+1⁄2 to 3+1⁄4 in) long, and clusters of 2–5  tiny female (pistillate) flowers enclosed in the protective bracts of a bud, with their red styles sticking out at the tip. The male catkins develop in the fall and remain over the winter. Each male flower on a catkin has a pair of bracts and four stamens.
American hazelnut produces edible nuts that mature at a time between July and October. Each nut is enclosed in two leaf-like bracts with irregularly laciniate margins.


The nuts produced by American hazelnut are a mast of squirrels, deer, turkey, woodpeckers, pheasants and other animals. The male catkins are a food staple of ruffed grouse throughout the winter.


The nuts are edible raw, although smaller than the more commonly cultivated filberts (Corylus maxima, Corylus colurna, Corylus avellana, and hybrids thereof).
Native Americans used Corylus americana for medicinal purposes.


Corylus americana is cultivated as an ornamental plant for native plant gardens, and in wildlife gardens to attract and keep fauna in an area. There are cultivated hybrids of Corylus americana with Corylus avellana which aim to combine the larger nuts of the latter with the former's resistance to a North American fungus Cryptosporella anomala.
It is a medium to fast-growing species, that suckers moderately, eventually producing a multi-stemmed, clump appearance.
It adapts well to a range of soil pH and types, but does best on well-drained loams. American hazelnut prefers full sun for best growth and development. Though it can grow and persist in partial shade, plant density and fruit production are greatly reduced.


Coryphantha macromeris (or the nipple beehive cactus) is a species of cactus in the United States and Mexico. In the Chihuhuan Desert, it is common and has a wide range. In the United States, it occurs naturally in Texas and New Mexico. It prefers to grown in the shade under other larger plants, growing in irregular clusters or mounds. In late summer, it blooms with purple or pink flowers and then bears green fruit.


The flimsy nest platform is built from fairly thin, and often thorny sticks. It has the appearance of a substantial dove's nest, and their almost round, white eggs can be seen from below. Usually three eggs are laid in a nest that is placed at the center of an isolated tree. The adults share all parental duties, and the chicks start clambering about before they are able to fly. The chicks are covered in dense brownish down, and are fed regurgitated food by the parents. The breeding season is July to August in Angola, April to November in Malawi, August to September in Zambia, Sept and December to April in Namibia, and all months in Zimbabwe and South Africa.


Four races are generally accepted, though more have been described:
C. c. molybdophanes (Clancey, 1964) – ne Angola to s Tanzania and n Mozambique
Description: Greyer chest plumage than bechuanae
C. c. pallidiceps (Neumann, 1899) – w Angola, Namibia and w Botswana
C. c. bechuanae (Roberts, 1932) – s Angola, ne Namibia, Botswana, s Zambia, c Zimbabwe and n South Africa
Description: Olive wash on chest plumage
C. c. concolor (A. Smith, 1833) – s Malawi, w Mozambique to Swaziland and e South Africa
Description: Only faint olive wash on chest plumage, paler grey below than bechuanae


The coscoroba swan (Coscoroba coscoroba) is a species of waterfowl endemic to southern South America. It is the smallest of the birds called “swans”, but still a large species of waterfowl. It belongs to the subfamily Anserinae in the family of ducks, swans, and geese, Anatidae. It is placed in the monotypic genus Coscoroba. The coscoroba swan is traditionally considered as an early branch from the common ancestor leading to true geese and swans, and recent genetic studies have associated a phylogenetic relationship between this species and the Cape Barren goose (Cereopsis novaehollandiae) as sister groups.


Male coscoroba swans weigh 3.8–5.4 kg (8.4–11.9 lb) and females weigh 3.2–4.5 kg (7.1–9.9 lb). The length is from 87.5 to 115 cm (34.4 to 45.3 in) and the wingspan is 155 to 160 cm (61 to 63 in). They have white plumage except for black tips to the outer six primary feathers, although this black is often barely visible on the closed wing. In flight, the black wing tips are conspicuous. The bird has a red beak, legs and feet. They look somewhat more like geese than swans. The female looks almost identical to the male. The cygnet is a patchy color, with brown and gray hues. The coscoroba swan lacks the patch of bare skin between the eyes and beak typical of swans. They look like a very small swan in body and look like a goose in the head. Eggs measure 89 X 61 mm, with averages of 82 to 94 53 to 67 mm, with an average weight of 170 grams and range from 129 to 203 grams


The coscoroba swan breeds in South America from southern Chile and central Argentina south to Tierra del Fuego and the Falkland Islands. In winter it flies north to central Chile, northern Argentina, Bolivia, Uruguay and the southeast tip of Brazil. Its habitat is well-vegetated swamps and lagoons. Its population is estimated at 10,000–25,000 birds.  It also has an ancient route to the Pantanal of Brazil and has been seen in large flocks in the Nhecolandia and Rio Negro regions.
Coscoroba swans have escaped or been deliberately released in to Florida, USA, but there is no evidence that the population is breeding and may only persist due to continuing releases or escapes.


The coscoroba swan feeds on various plant matter, small aquatic insects, and small fish. The female incubates the eggs, while the male stands guard and aggressively helps to protect the fledglings against predators after hatching. Coscoroba swans live to an age of approximately twenty years.


The dun-bar (Cosmia trapezina) is a moth of the family Noctuidae. It is a common Palearctic species.


The species occurs throughout almost the whole of Europe. In the north, the range extends to Middle Fennoscandia, in the east to the Urals. The species occurs in North Africa, Asia minor, Syria, Iraq, Iran, Caucasus, Central Asia to China, Korea and Japan (subspecies C. t. exigua (Butler, 1881)). It rises in the Alps up to 1600 m.


This is a very variable species, both in size (wingspan 28–38 mm) and colour. The ground colour of the forewings varies from pale buff to dark or reddish brown with three narrow fascia. The area between the inner two fascia is sometimes much darker than the surrounding ground colour and is marked with stigmata, often quite indistinct. Melanic forms occasionally occur. The hindwings vary from pale cream to dingy brown. This moth flies at night from July to September  and is attracted to light and sugar and sometimes to nectar-rich flowers.
The larva is green with yellow lines and black and white spots. It feeds on a variety of plants, chiefly trees and shrubs (see list below) and also on the larvae of other Lepidoptera species, even occasionally its own species. The species overwinters as an egg.
The flight season refers to the British Isles. This may vary in other parts of the range.


Acer – maple
Betula – birch
Corylus – hazel
Crataegus – hawthorn
Hippophae – sea-buckthorn
Lilium – lily
Malus – apple
Prunus
Pyrus – pear
Quercus – oak
Rhamnus – buckthorn
Rhododendron
Ribes – currant
Rubus – bramble
Salix – willow
Sorbus – rowan
Tilia – lime
Ulmus – wych elm
See.


The green blotched moth (Cosmodes elegans) is a moth of the family Noctuidae. It is found in New South Wales, Norfolk Island, Queensland, South Australia, Victoria, Western Australia and New Zealand.


This species was first described by Edward Donovan in 1805 under the name Phalaena elegans. Robert Hoare was unable to locate the type specimen for his 2017 publication.


Donovan originally described the species as follows:
First wings ferruginous, with three greenish spots edged with silver, the anterior one hooked : posterior wings reddish.
The caterpillars of this species grow to a length of about 3 cm and are bright green with dark spiracles on both sides. Adult moths are brown with sinuous green markings on their forewings, white hindwings fading to light brown along the edges, and a hairy crest just behind their heads. The adult's wingspan is about 40 mm. The green blotched moth has a distinctively shaped forewing and this and the characteristic patterns on its forewings ensures that this species is unlikely to be confused with any other.


The green blotched moth is native to Australia, although it sometimes arrives in New Zealand as a migrant or vagrant during the summer establishing temporary colonies. The adult moth lives in forest clearings from January to May and this is where its larvae cocoons among the foliage of its preferred food source.


This species is on the wing throughout the year but in New Zealand is more frequently recorded during the months of February to April.


The larvae feed on Lobelia species, Verbena species and Wahlenbergia species.


Cosmopepla lintneriana, the twice-stabbed stink bug, locally called the wee harlequin bug (particularly in Alberta), is a species of insect in the family Pentatomidae. Cosmopepla lintneriana was first described in 1798 by Johan Christian Fabricius as Cimex carnifex, and then again in 1865 by Thomas Say as Cosmopepla bimaculata. Cosmopepla lintneriana is hosted by a variety of plants, including milk thistle, echinacea, asparagus, oats, mint and goldenrod, and is widespread throughout North America, from Canada to Mexico. Adult C. lintneriana are black with a red, orange, or yellow band across the pronotum and a short red stripe along the midline, and two red spots at the apex of the scutellum. Nymph coloration ranges from red to white with black markings that change as they grow.


Cosmos bipinnatus, commonly called the garden cosmos or Mexican aster, is a medium-sized flowering herbaceous plant in the daisy family Asteraceae, native to the Americas. The species and its varieties and cultivars are popular as ornamental plants in temperate climate gardens.


Cosmos bipinnatus is considered a half-hardy annual, although plants may reappear via self-sowing for several years. The plant height varies from 2–6 ft (0.61–1.83 m) to (rarely) 9 ft (2.7 m). The cultivated varieties appear in shades of pink and purple as well as white. The branched stem is usually densely to occasionally occupied by fine, split up, rough trichomes, some specimens are completely hairless. The petiole itself is inconspicuous, winged, 10 (rarely to 15) mm long, sometimes the leaves are almost sessile.
The partial leaves are linear-filiform to narrow linear with a width of 0.5 to 1 (rarely to 1.7) mm; the tips are pointed, hardened, but not particularly sharp. Its foliage is finely cut into threadlike segments.  When flowering, the plant can become top heavy.  This problem is alleviated when grown in groups, as the bipinnate leaves interlock, and the colony supports itself.
The achenes become blackish, are smooth or short-bristly. Their shape is spindle-like. They are rounded off into a short, 0.5 to 1.7 mm long, but distinctly pronounced rostrum. The inner achenes are up to 18 mm long, their yellowish beaks are 4 to 5 (rarely to 10) mm long. A pappus is missing or it consists only of two to three awn-like, 1 to 3 mm large bristles.


The very conspicuous cup-shaped inflorescences have a diameter of usually 5 to 7 (rarely 8) cm and contain tongue and tubular flowers, which are surrounded by bracts. The outer bracts are usually eight and are ovate to lanceolate-tail-shaped, 7 to 15 mm long, 3 to 5 (rarely 6) mm wide. The inner bracts are ovate-lanceolate and 8 to 12 mm long. They are translucent with many black stripes and a clear edge up to 1 mm wide, sometimes with yellowish or pink pigments, the tip is ciliate. The sprout leaveshave gold-yellow, thread-like tips and protrude between the tubular flowers. The broadened base of these spreader leaves is translucent, provided with a yellow line. During flowering, the plant can sag under its weight. This problem can be solved by grouping the feet together so that the leaves hang together.
The mostly eight ray florets are pink to violet or white colored, at the base may show noticeable stains caused by anthocyanin. The tongues are reversely ovate shaped, have a length of usually 20 to 35 (16 to 40) mm and a width of usually 12 to 20 (8 to 25) mm. The tips are almost dull and have three broad, wavy teeth. Below that, they are greatly rejuvenated. In the center of the flower baskets is a large number of tubular flowers (also called disc florets), whose overgrown petals are yellow, turn white in the lower part and reach a length of 5 to 6 mm. The anthers are brownish-black and about 3 mm long, at the tips are short-triangular, translucent attachments with a length of 0.5 to 0.8 mm. The branches of the stylus are short and rather dull, with a length of 0.5 mm.


Garden Cosmos is native to Mexico, Guatemala and Costa Rica. Since it is used as an ornamental plant in many countries and prone to sedimentation, it is an invasive plant in many areas of the world. It has naturalized in scattered locations across North America, South America, the West Indies, Italy, Australia, and Asia, where it is a garden escape (introduced species) and in some habitats becoming a weed.


Cultivars of Cosmos bipinnatus in cultivation today include:
Apollo Series
'Apollo Carmine' agm
'Apollo Pink' agm
'Apollo White' agm
'Daydream' features a pink inner ring on a white background
Double Click Series  features semidouble to fully double flowers that resemble Japanese anemones (Anemone japonica)
'Double Click Cranberries'
'Double Click Rose Bonbon'
'Double Click Snow Puff'
'Double Click Vari Extra'
'Rubenza' agm
'Sensation', also known as 'Early Sensation', is a widely available mix of tall varieties
'Sensation Pinkie' agm
Sonata series
'Velouette'agm
'Versailles', developed for the cut flower trade, are shorter than the species, with heights remaining below three feet
'Versailles Dark Rose'
'Vesailles Tetra'
(those marked agm have gained the Royal Horticultural Society's Award of Garden Merit).


Growth characteristics of this plant include:
Germination takes between 7 and 10 days at the optimal temperature of 75 degrees Fahrenheit (24 °C); flowering begins between 60 and 90 days after germination
It prefers a soil pH between 6.0 and 8.5, reflecting its native habitat in the alkaline regions of Central America
Flowering is best in full sun, although partial shade is tolerated
Excessive rain can cause cultivation problems, due to the delicate nature of the stems. Heavy rain can cause breakage. Cosmos bipinnatus can tolerate heat as long as adequate moisture is provided, however, it does not handle droughts, strong winds or cold temperatures well. Snails, slugs and aphids have a taste for Cosmos bipinnatus. Successfully cultivated plants can mature 2 to 4 feet x 12 to 18 inches.


The flowers of Cosmos bipinnatus attract birds and butterflies, including the monarch butterfly. It can be part of butterfly gardening and pollinator/honey-bee habitat gardens.


Cosmos sulphureus is a species of flowering plant in the sunflower family Asteraceae, also known as sulfur cosmos and yellow cosmos. It is native to Mexico, Central America, and northern South America, and naturalized in other parts of North and South America as well as in Europe, Asia, and Australia.
This plant was declared invasive by the United States Southeast Exotic Pest Plant Council in 1996. The flowers of all Cosmos attract birds and butterflies, including the monarch butterfly.


This species of Cosmos is considered a half-hardy annual, although plants may re-appear via self-sowing for several years. Its foliage is opposite and pinnately divided. The plant height varies from 1–7 feet (30–210 cm). The original and its cultivars appear in shades of yellow, orange, and red. It is especially popular in Korea and Japan, where it is often seen in mass plantings along roadsides, following an initiative pursued by the Korean-Japanese botanist Woo Jang-choon.


Cultivars include:
'Brightness Red' agm
'Klondyke Mix', 'Polidor' consists of a variety of colors in shades from yellow to orange and scarlet
'Ladybird Dwarf Red', 'Ladybird Dwarf Gold', 'Ladybird Dwarf Orange', and 'Ladybird Dwarf Lemon' are shorter than the species at 40 cm. Their flowering is very early. The flowers have vibrant colors in hues of yellow, orange and scarlet. Another cultivar is named 'Bright Eyes'.
'The Diablo' reaches 75 cm with flowers of 5 cm intense orange red.
'The Polidor' reaches 75 cm and bears semi-double flowers in shades of golden yellow, orange and red.
'The Sunny Red' and 'Sunny Gold' have single flowers on stocky plants at 35 cm.
'The Sunset' reaches 90 cm. It bears double or semi-double flowers in shades of red or scarlet orange
'Tango' agm
(those marked agm have gained the Royal Horticultural Society's Award of Garden Merit).


Growth characteristics of this plant include:
Germination takes between 7 and 21 days at the optimal temperature of 75 degrees Fahrenheit; flowering begins between 50 and 60 days after germination
It prefers a soil pH between 6.0 and 8.5, reflecting its native habitat in the alkaline regions of Central America
Flowering is best in full sun, although partial shade is tolerated
The plant is tolerant to drought after germination, and is seldom subject to insect or disease damage; this vigor is attested by its status as a pest in some areas of the United States


Young shoots are eaten raw or cooked in Indonesia under the name of lalab or gudang.
The flowers are a dye, producing an orange-yellow dye, used in pre-Columbian America and later in southern Africa to dye wool. In Thailand, they are consumed in salads or herbal tea with the effect of inhibiting pancreatic lipase.
According to a Pakistani team (2017), in rats subjected to a high dose of paracetamol, extract of the plant has a hepatoprotective effect.
A Ukrainian publication (2017) attributes to a bread containing 10% dry extract of Cosmos sulphureus a good note for its organoleptic qualities.


Cossus cossus, the goat moth, is a moth of the family Cossidae. It is found in Northern Africa, Asia and Europe.


This is a large heavy moth with a wingspan of 68–96 mm. The wings are greyish brown and marked with fine dark cross lines. The moth flies from April to August depending on the location.
The caterpillars have a red/purple stripe across the back and a black head. They reach a length of 9–10 cm. The caterpillars feed in the trunks and branches of a wide variety of trees (see list below), taking three to five years to mature. The caterpillar holes can be found low on the stem (maximum 1.0–1.5 m above the ground).  When ready to pupate the caterpillar leaves the tree to find a suitable spot.
The species prefer humid environments.


Pliny reported in Natural History that a grub which he gives the name cossus was considered a Roman delicacy after it was fed with flour. Some writers have equated this with Cossus cossus, but Pliny specifies that his cossus is found in oak trees, which makes this identification unlikely. Pliny's cossus is more likely to have been the larva of the beetle Cerambyx heros.


The Cape robin-chat (Cossypha caffra) is a small passerine bird of the Old World flycatcher family Muscicapidae. It has a disjunct range from South Sudan to South Africa. The locally familiar and confiding species has colonized and benefited from a range of man-altered habitats, including city suburbs and farmstead woodlots. It is an accomplished songster like other robin-chats, but is rather less colourful than most, and frequents either drier settings or higher altitudes. It forages in the proximity of cover, in the open or in fairly well-lit environments. Its distribution resembles that of the karoo–olive complex of thrushes, but it prefers the bracken-briar fringes of Afromontane forest, and does not enter far into forest proper.  It is altitudinally segregated from the red-capped robin-chat, and is less of a skulker.


The Cape robin-chat occurs from South Sudan (mainly Imatong Mts, above 1,600 m) southwards to Uganda, the DRC (1,800 m – 3,475 m), Kenya, Tanzania, Zambia (above 1,800 m), Malawi (where common above 1,500 m), Zimbabwe, Namibia, South Africa, Swaziland and Lesotho. It is a mainly resident breeder in eastern and southern Africa, though some adults and juveniles may migrate more than 100 km to lower, warmer regions in winter. In their winter refuges, they may coexist with several other species of robin. Some are however year-round residents even at high altitudes. A five-year tenure of a breeding territory by the same pair is commonplace, and the maximum recorded life span is over 16 years.


In southern Africa, the Cape robin-chat is a common species at Afromontane forest edges, in forest scrub and ravines, fynbos, karoo, plantations, gardens and parks. Most areas with dense cover with scattered trees or song posts are however suitable. In dry areas they are restricted to thickets that fringe water courses. In southern Africa it is found from sea level up to 3,000 m where Leucosidea provides cover. It is absent from arid Karoo and Kalahari.
In tropical East Africa, the Cape robin-chat likewise frequents forest edge and gardens, but is restricted to the uplands. It occurs at 1,100 m in the Ulugurus, but generally upwards of 1,500 m in Uganda and the remainder of Tanzania, and above 1,800 m in Kenya. The tropical races are also at home at the edges of bamboo, in woodland, scrub, tea and coffee plantations, or in association with giant heather beside moorland streams, up to 3,400 m in altitude.


The sexes are similar. The Cape robin-chat measures 16–17 cm from bill tip to tail tip and weighs 28 g. The adult's upper parts are grey, with the mantle and secondary feathers tinged brownish olive. The blackish lores and ear coverts are separated from the crown by a prominent white supercilium. The chin, throat, central breast, rump, upper tail coverts and outer tail feathers are orange. The breast plumage moults to a deeper orange in colour for the non-breeding season. The central tail feathers are greyish-brown, and obscures the bright rufous outer tail feathers when the tail is closed. The belly is pale grey to white, and the undertail coverts buffy. The short, black bill is fairly straight, but with a slightly down-curved upper mandible. The legs and feet are black, and the eye is brown.
Juveniles have tails like the adults, but lack a supercilium. They are dark brown above and buff below, heavily marked with buff on the upper parts and grey-brown on the breast. The legs and feet are pinkish grey, and unlike other robin-chats, the soles of their feet are yellow. Immatures are like adults but retain some buff-tipped greater wing coverts.


The Cape robin-chat moves about singly with a hopping gait, and often perches in prominent positions. It also roosts singly up to 3 metres aboves ground, in dense cover. The tail is regularly jerked up to an angle of 60 degrees, and upon alighting it may flick the wings and rapidly fan the tail. It bathes daily, even in tide pools.


The Cape robin-chat has a harsh, low, trisyllabic alarm call, which may be rendered as WA-dur-dra, WA-de-da or TURR-da-da. It has given rise to several local names, including “Jan frederik”, which matches the rhythm of the call if the last syllables are run together. This call is also given year-round when arriving at, or departing from a roost.
The clear and ringing song is delivered in a series of short phrases, sometimes simultaneously by competing males. Singing peaks at dawn and dusk, and consists of passages of whistled syllables, cherooo-weet-weet-weeeet, followed by a pause. Each passage, consisting of 4 to 10 syllables, starts with a low, slurred whistle, which is followed by an improvised succession of whistled notes. From first light they usually sing from within, but near the top of a tree or bush, and at times uninterrupted for an hour or more. Singing may continue late into the evening, in pitch darkness. Males interrupt their singing during post-breeding moult. In the absence of her mate, females are said to sing equally well.
Anxious birds utter a plaintive, descending peeeeeuu note, for instance when their nestlings are threatened. Like other robin-chats, they may mimic other birds. One individual has been noted to mimic a total of 36 bird species.


Generally, the Cape robin-chat forages close to or on ground level, but will on occasion glean bark and foliage in tall trees. It prefers the cover of vegetation, but is not very shy. Invertebrates, small frogs and lizards are obtained in scrub or on leaf litter. In addition fruit and seeds are plucked from plants or eaten on the ground. Occasionally an insect may be hawked in the air, or invertebrates may be gleaned from leaves, branches or rocks.


The Cape robin-chats are monogamous and highly territorial nesters. A pair's territory usually comprises some fraction of a hectare, but its extent varies considerably depending on the habitat. The nest site is within 5 feet (regularly 0 – 2 feet) from the ground. It may be placed against a tree trunk, or on a broken stump in drift wood, and is often screened by overhanging vegetation.
The Cape robin-chat normally nests from June to November in the Western Cape and August to January elsewhere, but may nest at any time of the year. One of the pair will dowse its belly feathers and use the moisture to soften nesting material for easy shaping of the nest, while the other will bring the material to the nest. The female builds the cup-shaped nest of coarse vegetation, lined with animal hair, rootlets and other fine material. It is completed in 6 to 14 days, except when a nest is refurbished for a second clutch.
Two to three eggs are laid at one day intervals, and are incubated by the female for 14 to 19 days. The eggs measure 13 x 17 mm, and may be off-white, pinkish or pale blue, but always flecked with rusty brown, especially near the thicker end. Both parents will feed the nestlings during the subsequent 14 to 18 days, and for 5 to 7 weeks after they leave nest.
First breeding can occur at two years of age, but typically later, as potential territories are usually occupied. The Cape robin-chat is a host of the red-chested cuckoo. Predators often raid the nests, and replacement nests are common.


Four geographically isolated races are generally accepted, though Clancey (1980, 1981) distinguished several additional races with contiguous ranges.
Cossypha caffra iolaema Reichenow, 1900 – s South Sudan to Malawi and n Mozambique
Widespread in Kenya, Tanzania and e Uganda. Easterly locations include Mount Marsabit, the Taita Hills, East Usambaras and the East African montane forests, southwards to Njombe, Songea, Mbeya and Ufipa. Westerly populations are present at Mount Elgon and nearby sites, besides the Marungu highlands in the eastern DRC
Cossypha caffra kivuensis Schouteden, 1937 – sw Uganda, nw Tanzania and DRC, along rift
Ankole and Kigezi regions in s Uganda, and at Ngara, nw Tanzania
Cossypha caffra namaquensis W.L.Sclater, 1911 – Northern Cape and s Namibia
Especially in riparian vegetation of the lower Orange and Fish River regions
Somewhat larger than nominate, with broader white supercilium
Cossypha caffra caffra (Linnaeus, 1771) – e Zimbabwe, South Africa, Swaziland and Lesotho
Up to 2,200 m in Zimbabwe, where it doesn't breed below 1,400 m. South of the Limpopo however, it utilizes a greater range of habitats and altitudes, from sea level to 3,000 m, and is locally sympatric with red-capped and white-throated robin-chats.
Compared to C. c. iolaema it is slightly larger, less blackish on the head, with paler upper part plumage, less intense orange on breast, and greyer plumage below. Flanks still greyer in the far south, and chest plumage yellower.


Cota tinctoria, the golden marguerite, yellow chamomile, or oxeye chamomile, is a species of perennial flowering plant in the sunflower family. Other common names include dyer's chamomile, Boston daisy, and Paris daisy. In horticulture this plant is still widely referred to by its synonym Anthemis tinctoria.
It is a short-lived plant often treated as biennial, native to Europe, the Mediterranean and Western Asia and naturalized in scattered locations in North America. It has aromatic, bright green, feathery foliage. The serrate leaves are bi-pinnatifid (= finely divided) and downy beneath. It grows to a height of 60 cm (24 in).
It has yellow daisy-like terminal flower heads on long thin angular stems, blooming in profusion during the summer.
It has no culinary or commercial uses and only limited medicinal uses. However, it produces excellent yellow, buff and golden-orange dyes, used in the past for fabrics.
Cota tinctoria is grown in gardens for its bright attractive flowers and fine lacy foliage; there is a white-flowering form. Under the synonym Anthemis tinctoria, the cultivar ‘E.C. Buxton’ has gained the Royal Horticultural Society’s Award of Garden Merit. The popular seed-raised cultivar 'Kelwayi' has 5 cm wide, yellow flowers on 65 cm plants.


Adult wasps lay their eggs in tobacco hornworm (Manduca sexta) larvae in their 2nd or 3rd instar (each instar is a stage between moltings, i.e. the second instar is the life stage after the first molt and before the second molting) and at the same time injects symbiotic viruses into the hemocoel of the host along with some venom. The viruses knock down the internal defensive responses of the hornworm. The eggs hatch in the host hemocoel within two to three days and simultaneously release special cells from the egg's serosa.  These special cells, called teratocytes, grow to become giant cells visible to the naked eye. The teratocytes secrete hormones which work in tandem with the virus and the wasp venom to arrest the development of the host. Following hatching in the caterpillar, the wasp larvae will undergo 2 molts inside the host caterpillar’s hemocoel and, after 12 to 16 days post oviposition, the 3rd instar wasp larvae will emerge from the caterpillar and spin cocoons from which the adult wasps fly about 4 to 8 days later.
Not all of the parasite larvae will successfully emerge from the host. Dissection of post-emergence caterpillars revealed three categories of remaining larvae:
Dead or dying wasp larvae, in various stages of development, which had been partially or completely encapsulated by the host's immune system. The parasite has significant immunosuppressive capabilities, but the host's immune system is able to partially recover over a period of several days, so these may have been encapsulated at a very late stage.
Wasp larvae that were alive, but had exhibited reduced growth compared to the other larvae and might not have been able to reach the second instar stage.
Wasp larvae in the second instar, similar to those which had emerged successfully.
This insect has the shortest flagellated spermatozoa in animals, being 6.6 µm long (nucleus and flagellum), 8800 times shorter than the longest ones (Drosophila bifurca).
Cotesia pupae may themselves be hyperparasitized by wasps of the genus Hypopteromalus.


The polydnavirus will severely interfere with development of the host, Manduca sexta. Infected hosts will not undergo metamorphosis, and hosts with a particularly large number of parasites can reach higher weight in the first few instars than uninfected hosts. However, most hosts weigh less than unparasitized caterpillars and after they reach the fifth instar their feeding rate will reduce, causing their weight to decline significantly. The infected host will sometimes reach a supernumerary sixth instar if a high number of parasite larvae are present inside it. This is because there will be more competition for resources among the larger parasite population, causing them to develop more slowly. By contrast, the parasites may emerge in the fourth or even third instar if there are less of them than average. With less competition for resources, they will develop more quickly and be ready to emerge sooner.
In some cases, none of the parasites will emerge from a sixth-instar host. All of them will either die or fail to emerge. The hosts in this case would have been large enough to pupate at the end of the fifth instar. However, parasitized caterpillars have far higher levels of juvenile hormone (JH) than unparasitized caterpillars, and this prevents metamorphosis, causing the caterpillar to enter the supernumerary sixth instar instead. Some of these caterpillars will later reach a seventh instar stage, but they will still be unable to pupate and will die in this state.
Sixth-instar caterpillars below the threshold size for pupation at the end of the fifth instar are killed through parasite emergence.
Upon reaching the fifth instar, the caterpillar will enter a wandering stage, as is typical, but will not progress further and will not form a cocoon. The onset of the wandering stage is temporally delayed as well.
Approximately 8 hours before the wasp larvae emerge, the parasitized caterpillar's food consumption significantly declines. This change in behaviour may be a means to prevent the caterpillar from eating the wasp cocoons. At the same time as the caterpillar's food consumption declines, its locomotion also decreases significantly (that is, it moves around less). Without human intervention, the reduced appetite and locomotion are both permanent - the caterpillar will never return to its normal behaviour, even after the parasites have emerged.
Certain neuropeptides were found to accumulate in the neurosecretory system of the host, which were correlated to a change in molting behavior. Similar accumulation has been found in neural system of starving, unparasitized caterpillars, but not nearly to the same extent. The polydnavirus was found to inhibit development of the optic lobe of the host, causing morphological differences. One known hormone which has been focused upon, prothoracicotropic hormone (PTTH), was of particular interest. It is accumulated far more heavily in parasitized and starved hosts than in normal larvae. Other proteins found to increase in neurosecretory cells in both starved and parasitized larvae are: bombyxin, allatostatin, allatotropin, diuretic hormone, FMRFamide, and proctolin. Other proteins were found in increased concentration in hosts from which the wasps had already emerged, such as eclosion hormone and adipokinetic hormone.
The polydnavirus disallows these proteins from being released into the nervous system, instead causing them to accumulate in neurosecretory cells. Specifically with PTTH, due to the accumulation, is not released in sufficient amounts to stimulate the synthesis of ecdysteroids by the prothoracic glands, which will prevent subsequent development of the larvae. These hormones also allow the parasitized larva to survive longer without food or water, due to a slowdown of diuresis (urine production) and gut purge. This would help the larva to conserve water. Starved larvae can also ultimately molt and pupate if they are large enough, but this can be explained by the temporal difference in the beginning of accumulation. The mechanism behind neuropeptide accumulation is unknown. The polydnavirus is not the only factor affecting development of the host; teratocytes will have a similar effect, and it is likely that a large combination of different factors is needed to replicate the biological effects of parasitization.
Another extremely important effect of the virus is the suppression of the immune system of the host. This is accomplished by altering the behavior of host hemocytes, including inducing apoptosis. Within 24 hours of oviposition, the host is unable to encapsulate any antigen which enters its body, preventing it from attacking the wasp larvae.
Over a period of several days, the immune system will make a partial recovery. In experiments, its ability to encapsulate a harmless artificial stimuli had returned to near-normal after 8 days. After 10 days hemocyte functioning against injected E. coli bacteria had fully recovered. However, aspects of the immune system not involved in the initial response do not recover to the same extent. Parasitized caterpillars 10 days after oviposition were observed to suffer far higher mortality from the Pseudomonas aeruginosa bacterium than nonparasitized caterpillars, and had only very slight improvements in their immune response compared to caterpillars 1 hour post-oviposition.
Despite the immune system's partial recovery, by the 8-day point the wasp larvae have developed a resistance to the immune system by some other means. From an evolutionary standpoint, it is beneficial for the wasp larva that the host should recover its resistance to external pathogens without regaining the ability to destroy the parasite.
Larvae which have reached 8 days old can survive and eclose when transplanted into a new host which has not been exposed to the virus, although their chances of survival are significantly reduced. In experiments, 50% of the host larvae successfully encapsulated all of the parasitoids, and the mortality rate of wasp larvae in the remaining hosts varied significantly.
The wasp also injects venom along with the eggs and virus particles. The venom on its own will have a negligible effect on the host, but will enhance the effects of the virus when both are present.


Researchers were able to counter the decline in locomotion by surgically removing the host's supraesophageal ganglion (brain) during day 4 of the fifth instar, prior to parasite emergence. After the parasites emerged, the surgically-altered host moved about almost continuously, very similar to its "wandering" phase. However, this was not a restoration of the wandering phase, since during a genuine wandering phase the brain is necessary for locomotor activity. This surgery rendered the caterpillar unable to feed, so it is not known whether its drive to do so was also restored.


The Cotesia congregata bracovirus has one of the largest genomes known of any virus (567,670 base pairs), and is largely composed of introns, which is rare for a virus; 70% of the DNA is noncoding. The genome is arranged in 30 circles of DNA, which range in size from 5,000 to 40,000 base pairs. Of the 30, 29 circles code for at least one protein product. The genome is composed of 66% A-T residues. The top gene products are:
PTP proteins (protein tyrosine phosphatases), which will dephosphorylate tyrosine AA's on regulatory proteins. The PTP will interfere with certain cytoskeleton dynamics, which would be helpful in avoiding encapsulation. The PTPs found are more closely related to cellular PTPs than those found in viruses.
The second group of proteins are ank proteins, those with ankyrin repeat motifs. These are known to inhibit immune responses in vertebrates.
The third group of proteins are cysteine-rich proteins, are extremely similar to proteins excreted by the wasp teratocytes. These are suspected to inhibit translation of storage proteins such as arylphorin, which would leave more resources free for the parasite larvae.
The fourth group are cystatin proteins, which will inhibit cysteine proteases. These will inhibit the breakdown of the proteins in group 3. Cystatins are not a gene product previously found in viruses to date. They also likely have an immuno-suppressive function, based on similar proteins which have been found in parasitic nematodes.
The rest of the protein products have no known homologs and their function is not known. Much of what has been discovered makes it difficult to place the virus in a phylogenetic niche, and lends support to the theory that the virus was assembled, rather than evolved. The most closely related viruses are the nudiviruses and their baculovirus relatives, although this relatedness goes back approximately 75 million years.


Cotula australis is a species of plant in the daisy family known by the common names bachelor's buttons, annual buttonweed, southern waterbuttons and Australian waterbuttons. This small plant is native to Australia and New Zealand, but it is known in other areas of the world as a common weed (South America, California, Mexico, South Africa, etc.).
Cotula australis grows low to the ground in a thin mat with some slightly erect, spindly stems. The leaves are divided and subdivided into fringelike lobes. The plant flowers in inflorescences only a few millimetres wide containing minuscule yellow disc florets surrounded by greenish brown bracts and rudimentary ray florets that have been reduced to pistils with no stamens or corolla. The fruit is a tiny winged achene about a millimetre wide.


The pied butcherbird (Cracticus nigrogularis) is a songbird native to Australia. Described by John Gould in 1837, it is a black and white bird  28 to 32 cm (11 to 12.5 in) long with a long hooked bill. Its head and throat are black, making a distinctive hood; the mantle and much of the tail and wings are also black. The neck, underparts and outer wing feathers are white. The juvenile and immature birds are predominantly brown and white. As they mature their brown feathers are replaced by black feathers. There are two recognised subspecies of pied butcherbird.
Within its range, the pied butcherbird is generally sedentary. Common in woodlands and in urban environments, it is carnivorous, eating insects and small vertebrates including birds. A tame and inquisitive bird, the pied butcherbird has been known to accept food from humans. It nests in trees, constructing a cup-shaped structure out of sticks and laying two to five eggs. The pied butcherbird engages in cooperative breeding, with a mated pair sometimes assisted by several helper birds. The troop is territorial, defending the nesting site from intruders. The International Union for Conservation of Nature (IUCN) has assessed the pied butcherbird as being of least concern on account of its large range and apparently stable population.


The pied butcherbird was first described by the ornithologist John Gould in 1837 as Vanga nigrogularis. The type specimen was collected near Sydney. The species name is from the Latin words niger (black), and gula (throat). Gould described Cracticus picatus in 1848 from northern Australia, calling it "A miniature representative of, and nearly allied to, but distinct from, Cracticus nigrogularis." The word picatus is Latin for "daubed with pitch", hence "black patches. This was reclassified as a subspecies of C. nigrogularis. Gregory Mathews described subspecies inkermani from Queensland and subspecies mellori from Victoria and South Australia in 1912, on the basis of smaller and larger size than the nominate subspecies respectively. Both are now regarded as inseparable from the nominate subspecies. Mathews described subspecies kalgoorli from Kalgoorlie in 1912 on the basis of its longer bill than the nominate subspecies, but is regarded today as part of subspecies picatus.
Two subspecies are recognised today. The nominate subspecies nigrogularis is found across eastern Australia, and subspecies picatus is found in the Northern Territory, Western Australia and northern South Australia. The latter subspecies has a broader (3.7 cm (1.5 in) wide) white collar and a more whitish rump, with specimens becoming smaller in the more northern parts of the range. The border between the two subspecies lies in the Gulf Country and is known as the Carpentarian Barrier. Although there is a demarcation in physical characters, this is not borne out genetically, and birds from northwestern Australia have affinities with the eastern subspecies. Analysis of mitochondrial DNA sequences indicates the pied butcherbird has expanded rapidly from many refugia during the Pleistocene.
The pied butcherbird is one of six (or seven) members of the genus Cracticus, known colloquially as butcherbirds. Within the genus, it is most closely related to the Tagula butcherbird (C. louisiadensis) and hooded butcherbird (C. cassicus). The three form a monophyletic group within the genus, having diverged from ancestors of the grey butcherbird around five million years ago. The butcherbirds, Australian magpie (Gymnorhina tibicen) and currawongs (Strepera spp.) were placed in the family Cracticidae in 1914 by John Albert Leach after he had studied their musculature. American ornithologists Charles Sibley and Jon Ahlquist recognised the close relationship between woodswallows and the butcherbirds in 1985, and combined them into a Cracticini clade, which became the family Artamidae in 1994.
"Pied butcherbird" has been designated the official name by the International Ornithological Committee (IOC). Black-throated butcherbird is an alternative common name, as are Break o'day boy and organbird. Leach also called it the black-throated crow shrike, a name used by Gould for subspecies nigrogularis while calling subspecies picatus the pied crow-shrike. ‘Jackeroo’ is a colloquial name from the Musgrave Ranges in Central Australia. Gould recorded Ka-ra-a-ra as a name used by indigenous people of Darwin. The Ngarluma people of the western Pilbara knew it as gurrbaru. In the Yuwaaliyaay dialect of the Gamilaraay language of southeastern Australia, it is buubuurrbu. Names recorded from central Australia include alpirtaka and urbura in the Upper Arrernte language.


Like other butcherbirds, the pied butcherbird is stockily built with short legs and a relatively large head. It ranges from 28 to 32 cm (11 to 12.5 in) long, averaging around 31 cm (12 in), with a 51 cm (20 in) wingspan and weight of around 120 g (4 oz). The wings are fairly long, extending to half-way along the tail when folded. Its plumage is almost wholly black and white, with very little difference between the sexes. It has a black head, nape and throat, giving it the appearance of a black hood, which is bounded by a white neck collar, which is around 3.2 cm (1 in) wide. The black hood is slightly glossy in bright light, can fade a little with age, and is slightly duller and more brownish in the adult female. The neck collar in the female is slightly narrower at around 2.5 cm (1 in) and is a grey-white rather than white. Several stiff black bristles up to 1.5 cm (1 in) long arise from the lower lores. The upper mantle and a few of the front scapulars are white, contrasting sharply with the black lower mantle and the rest of the scapulars. The rump is pale grey, and the upper tail coverts are white. The tail is rather long, with a rounded or wedge-shaped tip. It has twelve rectrices, which are black in colour. The tail tip and outer wing feathers are white. The underparts are white. The eyes are a dark brown, the legs grey and the bill a pale bluish grey tipped with black, with a prominent hook at the end.
The juvenile pied butcherbird has dark brown instead of black plumage, lacks the pale collar and has a cream to buff lores, chin, and upper throat, becoming more brown on the lower throat and breast. Its underparts are off-white to cream. The bill is dark brown. In its first year, it moults into its first immature plumage, which resembles that of the juvenile, but has a more extensive dark brown throat. Its bill is blue-grey with a dark brown or blackish tip.


The pied butcherbird has been considered the most accomplished songbird in Australia, its song described as a "magic flute" by one writer, richer and clearer than the Australian magpie. Song melodies vary across the continent and no single song is sung by the whole population. There is no clear demarcation between simple calls and elaborate songs: duets, and even larger choirs, are common. The species improvises extensively in creating new and complex melodies. One of its calls has been likened to the opening bars of Beethoven's Fifth Symphony. Singing often takes place at dawn, and rarely late in the day. Pied butcherbirds sometimes sing on moonlit nights.
Three types of song have been described: the day song is the most common, sung by birds alone or in pairs as a chorus or an antiphonal duet, generally over the course of the day and while the birds are in flight. It appears to promote bonding and act as communication. The whisper song is sung more commonly in wet or windy weather, the singer sitting in a tree warbling soft and complex harmonies for up to 45 minutes, often mimicking many other bird species as well as dogs barking, lambs bleating or even people whistling. In the breeding season, pied butcherbirds sing the breeding song at night until dawn, when they switch to the day song. This song is longer and more complex than the day song. In response to threats, pied butcherbirds may chatter or make a harmonic alarm call composed of short, loud descending notes.


The black hood helps distinguish the pied butcherbird from other butcherbirds, the Australian magpie and much smaller magpie-lark, the latter of which also has a much smaller beak. It has a higher-pitched call than the grey butcherbird and inhabits more open habitat. The juvenile pied butcherbird resembles the grey butcherbird: it has a buff upper throat and dark brown instead of black plumage.


The pied butcherbird is found across much of Australia, excepting the far south of the mainland, and Tasmania. It is only rarely recorded in the Sydney Basin, and absent from the Illawarra, Southern Tablelands and south coast of New South Wales. In Victoria it is found along the Murray Valley and west of Chiltern. In South Australia it is not found in the northeast of the state, nor on the Adelaide plain. It is found across Western Australia, though is absent from the Great Sandy Desert. It is generally sedentary across most of its range, with minimal seasonal movements.
It is a bird of open sclerophyll forests, eucalypt and acacia woodlands and scrublands, with sparse or no understory, or low cover with shrubs such as Triodia, Lomandra or Hibbertia. It is less common in mallee scrub. In arid areas and northern Australia, it is more restricted to woodland alongside rivers and billabongs. It has become more common in southwest Western Australia with land clearing, though has become rare around Darwin on account of urban development.


The pied butcherbird is listed as being a species of least concern by the IUCN, on account of its large range and stable population with no evidence of any significant decline.


The pied butcherbird is thought to be monogamous, though its breeding habits have not been much studied. There is evidence of cooperative breeding, with some mated pairs being assisted by up to several other helper birds. These individuals help feed young and defend the nest. These pairs or small groups defend their territory from intruders, mobbing and chasing raptors and other birds, and occasionally dogs or people. They may attack animals (and people) that venture too close to the nest, with one bird coming front-on while the other may approach from behind.
The maximum age recorded from banding has been 22 years 1.7 months, for an individual banded in Rockhampton in June 1988 and recovered in August 2010–7 km away. The bird was injured and had to be euthanased.


Across most of its range, the pied butcherbird can generally be found breeding from winter to summer; eggs are laid anywhere from July to December, but mostly from September to November, and young can be present in the nest from August till February. There are reports of breeding outside these months, however. The nest is constructed of dry sticks with a finer material such as dried grass, black roly poly (Sclerolaena muricata), bark and leaves forming a cup-shaped interior. It is located in the fork of a tree, often among foliage and inconspicuous. The clutch consists of two to five (most commonly three or four) oval eggs blotched with brown over a base colour of various shades of pale greyish- or brownish-green. Larger clutches have been recorded, such as at Jandowae in Queensland, where two pairs laid eggs and were sharing incubation duties. Eggs of subspecies nigrogularis are larger, at around 33 mm long by 24 mm (1.3 by 0.95 in) wide, while those of subspecies picatus are around 31 mm long by 22 mm (1.2 by 0.85 in) wide. Incubation takes 19 to 21 days, with the eggs laid up to 48 hours apart and hatching at a similar interval. Like all passerines, the chicks are altricial—they are born naked or sparsely covered in down and blind. They spend anywhere from 25 to 33 days in the nest before fledging, though may leave the nest early if disturbed. They are fed by parents and helper birds. Brood parasites recorded include the pallid cuckoo (Cacomantis pallidus) and channel-billed cuckoo (Scythrops novaehollandiae).


The pied butcherbird is carnivorous, and eats insects such as beetles, bugs, ants, caterpillars, and cockroaches, as well as spiders and worms. It preys on vertebrates up to the size of such animals as frogs, skinks, mice, and small birds such as the silvereye  (Zosterops lateralis), house sparrow (Passer domesticus), double-barred finch (Taeniopygia bichenovii), willie wagtail (Rhipidura leucophrys), and grey teal (Anas gracilis) duckling. It has been looked upon favourably by farmers as it hunts such pests as grasshoppers and rodents. Some individuals look for scraps around houses and picnic sites, and can become tame enough to be fed by people, either by hand or by tossing food in the air. The pied butcherbird also eats fruit, such as those of sandpaper figs (Ficus coronata), native cherry (Exocarpos cupressiformis), African boxthorn (Lycium ferocissimum) and grapes (Vitis vinifera), and nectar of the Darwin woollybutt (Eucalyptus miniata).
The pied butcherbird often perches on a fencepost, stump or branch while foraging for prey. It generally pounces on victims on the ground and eats them there. At times, it may hop or run along hunting ground-based food, and occasionally seize flying insects. It generally forages alone, or occasionally in pairs. The pied butcherbird has been observed hunting collaboratively with the Australian hobby, either picking off common starlings or rufous-throated honeyeaters disturbed by the larger hobby, or flushing out small birds from bushes, which the larger bird then hunts. The pied butcherbird sometimes stores food items by impaling them on a stick or on barbed wire, or shoving them in a nook or crevice.


Several Australian and international composers have been inspired by and written music incorporating the songs of the pied butcherbird, including Henry Tate, David Lumsdaine (who described it as "a virtuoso of composition and improvisation"), Don Harper, Olivier Messiaen, Elaine Barkin, John Rodgers, Ron Nagorcka, and John Williamson. In the dance 'Bird Song' by Siobhan Davies, the main central solo was accompanied by the call of a pied butcherbird and this same sound provided inspiration to much of the dance, including the improvisational aspects. Composer and researcher Hollis Taylor has studied pied butcherbird song for 12 years, and has released a double CD called Absolute Bird based on fifty-plus pied butcherbird nocturnal solo songs. Taylor's 'Is Birdsong Music? Outback Encounters with an Australian Songbird' offers portraits of the remote locations where the species is found.
In the now extinct Warray language spoken on the Adelaide River in Arnhem Land, Cracticus Nigrogularis was known as lopolopo.


The grey butcherbird (Cracticus torquatus) is a widely distributed species endemic to Australia. It occurs in a range of different habitats including arid, semi-arid and temperate zones. It is found across southern Australia, but is absent from the deserts of central Australia and the monsoon tropics of northern Australia.  It has a characteristic "rollicking" birdsong. It appears to be adapting well to city living, and can be encountered in the suburbs of many Australian cities including Brisbane, Melbourne, and Sydney. The grey butcherbird preys on small vertebrates including other birds.
Other birds in the same family include the Australian magpie, the currawongs, woodswallows and other members of the butcherbird genus Cracticus.


The grey butcherbird was first described by the English ornithologist John Latham in 1801 under the binomial name Lanius torquatus.
Closely related species include the silver-backed butcherbird (Cracticus argenteus) and the black-backed butcherbird (Cracticus mentalis). The silver-backed butcherbird (Cracticus argenteus) from Arnhem Land and northwestern Australia over to Port Hedland, originally described by John Gould in 1841, was later deemed to be a subspecies of the grey butcherbird. Recently, however, it has again been re-described as a separate species. The silver-backed butcherbird has two subspecies C. argenteus argenteus and C. a. colletti. The black-backed butcherbird occurs in Australia on the Cape York Peninsula and in Papua New Guinea and has two subspecies.