Most garden plants of S. vulgaris are cultivars, the majority of which do not exceed 4–5 m (13–16 ft) tall. Between 1876 and 1927, the nurseryman Victor Lemoine of Nancy, France, introduced over 153 named cultivars, many of which are considered classics and still in commerce today. Lemoine's "French lilacs" extended the limited color range to include deeper, more saturated hues, and many of them are double-flowered "sports", with the stamens replaced by extra petals.


In the UK the following cultivars of Syringa vulgaris have received the Royal Horticultural Society's Award of Garden Merit:
With single flowers:
'Andenken an Ludwig Späth' (deep pink/red)
'Esther Staley' (S. × hyacinthiflora - pale lilac flowers)
'Firmament' (pale lilac-blue)
'Sensation' (purple flowers edged white)
'Vestale' (pure white flowers)
With double flowers:
'Katherine Havemeyer' (lilac)
'Madame Lemoine' (white)
'Mrs Edward Harding' (deep pink/red)
'Primrose' (pale yellow flowers)


The flowers of common lilac are edible and used for flavoring honeys, sugars, food and other sweets.


This species can be found in the entire Palearctic realm, across Europe as far north as Scandinavia and European Russia. It is also present in Israel and North Asia, east to China, Mongolia, Korea, and Japan, and in North Africa.


These flies inhabit the vegetation of humid regions, meadows, woodland, forests, forest edges, clearings, heath and moorland and natural gardens.


Tachina fera can reach a length of 9–14 millimetres (0.35–0.55 in), with a wingspan of 16–27 mm. These tachinids show a grayish upperside of the thorax, due to dense pollinosity, with regular black stripes. The abdomen is yellow orange with a wide black dorsal stripe ending in a point . They are bristly on the thorax and abdomen, especially towards the tip, where they have long thorn-shaped, protruding black bristles. Close to the thorax there is a striking, orange-red and shiny 'bump' called postscutellum, with a thin black edge. The head is yellowish colored, with long antennae, whose second segment is yellow, while the third, much shorter, is black. The back of the head shows yellowish hairs and the large compound eyes are red in color. The size of the eyes in relation to the head is sex dependent. The palps of the mouthparts are long, thin and thread like. The wings are slightly yellow tinged, show a brownish yellow veining and are yellow brown at the base. Calyptrae are whitish yellow. The legs are predominantly yellowish, but in the male they are usually dark with a yellow tip.
This species is very similar to Tachina magnicornis, that is a little smaller, has a medial dorsal band forming lozenges and that does not terminate in a point.


There are two generations per year, as this species is bivoltine. Adults can be seen from the end April to the end June and from mid-July to mid-October. They feed on nectar and pollen of flowers, especially of Asteraceae (Cirsium arvense) and Apiaceae (Heracleum sphondylium). Females do not lay eggs, like a parasitic wasp, in the caterpillar, but on the leaves of a potential nutritive plant of the host caterpillars. When the eggs hatch the young larvae enter the body of the caterpillars (one larva per caterpillar) and eat them from the inside. In fact larvae are parasitoids of the caterpillars  and larvae of other young insects, but mainly of moths in the families Noctuidae and Lymantriidae. In Britain afflicted species include the broom moth (Ceramica pisi), the dun-bar (Cosmia trapezina), small Quaker (Orthosia cruda) and common Quaker (Orthosia cerasi). They also parasitize caterpillars of the gypsy moth (Lymantria dispar), the black arches (Lymantria monacha), and the pine beauty (Panolis flammea). Pupation occurs outside the host in the soil litter. After about two weeks the adult flies will appear. This species has a potential economic importance in forest pest control.


Tachopteryx thoreyi, commonly known as the gray petaltail and Thorey's grayback, is a species of dragonfly. It is native to the East Coast of the United States as far north as New York, as far south as Florida, and as far west as Texas. This species is the only member of the monotypic genus Tachopteryx.
The gray petaltail lives in highlands, woodlands, and deciduous forests with permanent seeps, often indicated by the presence of skunk cabbage and ferns.
The gray petaltail is primarily gray and black in color; the thorax is usually entirely gray, while the abdomen is gray and black. The adult is 7.1 to 8.0 centimeters in length.


The least grebe (Tachybaptus dominicus), an aquatic bird, is the smallest member of the grebe family. It occurs in the New World from the southwestern United States and Mexico to Argentina, and also on Trinidad and Tobago, the Bahamas and the Greater Antilles.


The least grebe ranges in length from 21–27 cm (8.3–10.6 in) (depending on the subspecies) and in weight from 112–180 g (4.0–6.3 oz). Weights are variable based on region and subspecies, being smaller in Panama, where males weighed a mean of 129 g (4.6 oz) against the females 116 g (4.1 oz) and larger in the West Indies, where the sexes weigh a mean of 161 g (5.7 oz) and 133 g (4.7 oz), respectively. In Texas, size is intermediate at 139 g (4.9 oz) and 122 g (4.3 oz). Even in the largest races, the least grebe is still smaller and lighter than any other grebe species. Like all grebes, its legs are set far back on its body and it cannot walk well, though it is an excellent swimmer and diver. Small and plump, with a fairly short, sharp-pointed beak and bright yellow eyes, it typically appears quite dark all over.
The breeding adult is brownish grey above with a darker blackish crown and throat. It has a brownish chest and pale underparts. It shows a white wing patch in flight. Non-breeding birds are paler with a whitish throat, and immatures are paler and greyer than adults. Unlike all other members of its genus, it lacks any chestnut coloring on its neck.


There are five recognized subspecies of least grebe, separated principally by size and color.
T. d. brachypterus – (Chapman, 1899): is found from southern Texas and Mexico south to Panama.
T. d. bangsi – (van Rossem & Hachisuka, 1937): is restricted to southern Baja California, Mexico. It is the smallest and palest of the subspecies.
T. d. dominicus – (Linnaeus, 1766): nominate, is found in the northern Caribbean, including the Bahamas, Greater Antilles, Virgin Islands and southern Florida.
T. d. brachyrhynchus or T. d. speciosus – (Chapman, 1899): is found in South America, from Colombia, Venezuela, Trinidad and Tobago south to northern Argentina and southern Brazil.
T. d. eisenmanni – Storer & Getty, 1985: is restricted to the lowlands of western Ecuador. This subspecies is not recognized by all authorities.
Its genus name, Tachybaptus, is a combination of two Greek words—takhus meaning fast and baptos meaning diving, or sinking under. The specific name dominicus refers to the Caribbean island of Hispaniola, which was formerly known as Santo Domingo. As its English name suggests, the least grebe is overall the smallest member of the grebe family. It is the only member of its genus found in the New World; the four other members of the genus Tachybaptus reside in the Old World and Australasia.


Least grebes are found in a wide variety of wetland habitats, including freshwater ponds, lakes, and marshes, slow-flowing streams and rivers, roadside ditches, and mangrove swamps. In general, they prefer bodies of water with significant amounts of vegetative cover, particularly along the edges; they will even use wetlands which are almost completely overgrown. They may choose small, temporary bodies of water to breed, in an effort to avoid predation of their chicks by large fish.


For much of the year, least grebes are found singly or in pairs; however, when not breeding, they sometimes gather in flocks of 20 or more.


The least grebe eats a variety of aquatic life, including small fish, crustaceans, frogs and aquatic insects. Like all grebes, it pursues much of its prey under water. During active feeding bouts, it spends an average of 12.5 seconds beneath the surface on each dive, with surface pauses ranging from 2–24 seconds.


Least grebes breed throughout the year. Those in the tropics tend to breed during the rainy season, while active nests have been found in every month of the year in Texas. Each pair builds a compact floating nest of vegetation—typically a variety of aquatic weeds—which is anchored to rooted plants in still open water as deep as 1.5 m (4.9 ft). The female lays three to six white eggs, though the damp nest material soon stains them with brown. Both adults incubate the eggs, which hatch after 21 days. The striped young are sometimes carried on the adult's back.


The breeding call has been likened to a horse whinnying.


The least grebe, while a species of least concern, experiences a number of predators, particularly early in life. Large fish species and turtles are reported to take young grebes, and bird-eating raptors, including the bat falcon and the golden eagle, have been observed taking adult birds.


Tachycines asynamorus is a cave cricket and the type species of the genus Tachycines (Rhaphidophoridae). In English-speaking countries it is known as the greenhouse camel cricket or greenhouse stone cricket for its propensity for living in greenhouses. It was first described in 1902 by Russian entomologist Nicolai Adelung. Some authorities have placed this species in the genus Diestrammena, but it has now restored to its basonym.


Tachycines asynamorus is a medium-sized, apterous camel cricket. Its body length ranges from 11.3–14.6 mm (0.4–0.6 in). It has very long antennae, palps, and cerci. The female has a long, gently upcurved ovipositor, 10.7–12 mm (0.4–0.5 in) in length.
Originating in the caves of eastern Asia, it is omnivorous, sometimes carnivorous, or a scavenger of dead insects and other organic material.


It is native to Asia, including Korea, but has long been found especially in heated European greenhouses.
People in the United States were asked to survey their homes for presence or absence of camel crickets such as those of this genus and return photographs and/or specimens to North Carolina State University for further research. Researchers including Rob Dunn have found that introduced greenhouse camel crickets were reported much more commonly than the native North American camel crickets of the genus Ceuthophilus.


The mangrove swallow (Tachycineta albilinea) is a passerine bird in the swallow family that breeds in coastal regions from Mexico through Central America to Panama. It has blue-green upperparts, blackish flight feathers, a white rump, a black tail, and white underparts. It can be identified by the supraloral white streak, the white line near its eye, which only occurs in two other species of Tachycineta: the violet-green swallow and the white-rumped swallow. The sexes, although similar in plumage, differ slightly in size. The juveniles have grey-brown upperparts and white-washed underparts. This swallow's song is generally described as a soft trilling, with a rolled jeerrt call, and a sharp alarm note.
The mangrove swallow is very territorial when breeding, much like the related tree swallow. Its nest is normally built in a hole or crevice near water and less than 2 metres (7 ft) above the ground. This species usually feeds alone when breeding, but will feed in groups when not. It normally forages closer to the nest when hunting for its chicks, but will go much further when foraging for itself. In between foraging attempts, it is frequently seen perching near water. It is an aerial insectivore and eats unusually large prey for its size.
With an estimated population of at least 500,000 individuals, the mangrove swallow is classified as a species of least concern by the International Union for Conservation of Nature (IUCN). Its numbers are decreasing, although not fast enough for it to be classified as vulnerable. Little is known about the predation of this species, although it is a host of Sternostoma hirundinis, a type of nasal mite. It has also been known to lose nests both to termites and black flies.


The mangrove swallow was formally described in 1863 as Petrochelidon albilinea by American amateur ornithologist George Newbold Lawrence. Its current genus, Tachycineta, was originally described in 1850 by the German ornithologist Jean Cabanis. The genus name Tachycineta is from Ancient Greek takhukinetos, "moving quickly", and the specific albilinea is from Latin albus, "white", and linea, "line".
The Tachycineta species are members of the swallow family of birds, and are placed in the Hirundininae subfamily, which comprises all swallows and martins except the very distinctive river martins. DNA sequence studies suggest that there are three major groupings within the Hirundininae, broadly correlating with the type of nest built. These groups are the "core martins", including burrowing species like the sand martin, the "nest-adopters", which are birds that utilise natural cavities, and the "mud nest builders" such as the Delichon house martins. The Tachycineta species belong to the "nest-adopter" group.
All nine Tachycineta species have glossy blue or green backs and white underparts, but the five species with white rumps – the mangrove swallow, Tumbes swallow, white-winged swallow, white-rumped swallow and Chilean swallow – are particularly closely related, the first three and the last two forming two superspecies. The Tumbes swallow of coastal Peru was formerly considered to be a subspecies of the mangrove swallow, but its calls, behaviour, and cytochrome b data indicate that it should be considered as a separate species. It is also differentiated from the mangrove swallow by its lack of a supraloral white line and by its slight difference in size.


A relatively small swallow, the mangrove swallow is 11–12 centimetres (4.3–4.7 in) long and weighs about 14 grams (0.5 oz). The adult has iridescent blue-green upperparts, white underparts, rump, and undertail- and wing-coverts, and blackish tail and flight feathers. The feathers are greener when fresh and bluer when worn. The white underparts sometimes have faint, dark shaft streaks. The bill is small and black, about 11 millimetres (0.43 in) long. The iris is a dark brown, and the tarsus and toes range in colour from black to fuscous-brown. The lores are black and have a thin white line above them. Two other species of Tachycineta have this distinctive feature: the violet-green swallow and the white-rumped swallow. The adult's tail is only slightly forked. The sexes are similar, although they differ slightly in size. Compared to the male, the female has a slightly longer tail and slightly shorter wings. The juvenile is dull grey-brown above and grey-brown washed white below. Occasionally, the juvenile's upperparts have a subtle, greenish gloss.
The call of the mangrove swallow is a rolled "jeerrrt", or a "chriet". The song is frequently described as a soft trilling. It uses a short sharp alarm note.


This swallow is native to Mexico and all of Central America (Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Panama). It is usually found near low-lying bodies of water and mangrove forests, which gave rise to the common name. It has also been recorded in intertidal zones. In Mexico, it is not typically found above 600 metres (2,000 ft). In Costa Rica, it has been found to occur as high as 1,000 metres (3,300 ft), but it normally occurs between 500 metres (1,600 ft) and sea level. It is rarely found in the highlands. The mangrove swallow is also vagrant to the United States, where it was first recorded in 2002, in Florida. Although the mangrove swallow is a full-time resident of its range, there are probably some post-breeding movements.


The mangrove swallow is closely associated with fairly still, open water, and is often found in small flocks over rivers or lakes when not breeding. Its flight path is normally direct and low over water. It flies with quick wingbeats and some gliding. In between foraging attempts, it can frequently be seen to perch.


The mangrove swallow is a solitary bird; its nests are not found closer than 50 metres (160 ft) away from each other, and usually have about 300 metres (1,000 ft) separating them. The nest itself is built in natural or artificial cavities near water, usually in a tree stump or dead tree. It is also not uncommon for it to nest in nest boxes. The nest is a few centimetres deep and made with grass, fine stems, moss, and a few leaves and sticks. It is padded with feathers. The nest is normally found to occur below 2 metres (7 ft). While the nest is built relatively low, it is still normally above the water level of a typical flood. Sites include tree holes and crevices in rock or bridges.


During its five-month breeding season, the mangrove swallow typically lays two broods. The data suggests that the breeding season is from approximately January to July in Central America, and from around March to June or July in Mexico. Like the related tree swallow, this species is very aggressive to other hirundines when breeding and is very territorial.
This swallow is socially monogamous, with some extra-pair mating. For example, about 15% of nestlings and about 25% of broods are developed through extra-pair paternity. A nest with extra-pair young is, on average, about 430 metres (1,410 ft) away from its nearest neighbour. Extra-pair young are also correlated with the breeding synchrony index, or the percentage of females fertile simultaneously. The fact that the laying of eggs is not synchronized within a population is due to the long breeding season of the mangrove swallow. This swallow also displays paternity assurance behaviour. For example, males follow fertile females more often than females follow males. The period of fertility is from six days before the first egg is laid until the second to last egg is laid.
The clutch is three to five white eggs which hatch in 17 days. On average the eggs measure 17.3 mm × 12.8 mm (0.68 in × 0.50 in) and weigh about 1.6 grams (0.056 oz). The eggs hatch asynchronously, with about a 60% hatchability. The nestlings are fed by both parents for 23–27 days to fledging. Usually, there is only one successful fledgling per nest.


The mangrove swallow subsists primarily on a diet of small, flying insects, including large species such as dragonflies and bees. The prey it feeds on is large for a bird of its size. This swallow usually feeds close over bays, lakes, and large rivers, but sometimes can be found to forage 30 metres (98 ft) or more above the water. It normally forages in the early morning and late afternoon, with nestlings being fed just after sunrise and before sunset. Non-breeding mangrove swallows normally forage in small flocks, although when breeding, it feeds alone or in pairs.
The mangrove swallow typically stays within about 100 metres (330 ft) of its nest when it is foraging for the nestlings. But, when hunting for itself, it has been recorded to go as far out as 200 metres (660 ft) from its nest. Ordinarily, it will feed within its own territory.


Not much is known about the predators and parasites of the mangrove swallow, although it has been known to lose nests to termites and black flies. The black flies are mainly local and typically only affect artificial nest boxes. The prevalence of the flies is linked to nearby streams and is dependent on weather conditions. This swallow is a host to the parasite Sternostoma hirundinis, a type of nasal mite.


As of 2016, the mangrove swallow is classified as least concern by the IUCN. There is some evidence that the population is decreasing. This is probably due to habitat loss or the use of pesticides. The justification for classifying this species as least concern is its large population, estimated to be greater than 500,000 individuals, and its extremely large range, estimated to be about 3,170,000 square kilometres (1,220,000 sq mi). Although the population is decreasing, it is not decreasing rapidly enough to be classified as a vulnerable species.


The tree swallow (Tachycineta bicolor) is a migratory bird of the family Hirundinidae. Found in the Americas, the tree swallow was first described in 1807 by French ornithologist Louis Vieillot as Hirundo bicolor. It has since been moved to its current genus, Tachycineta, within which its phylogenetic placement is debated. The tree swallow has glossy blue-green upperparts, with the exception of the blackish wings and tail, and white underparts. The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is generally duller than the male, and the first-year female has mostly brown upperparts, with some blue feathers. Juveniles have brown upperparts, and a grey-brown-washed breast. The tree swallow breeds in the US and Canada. It winters along southern US coasts south, along the Gulf Coast, to Panama and the northwestern coast of South America, and in the West Indies.
The tree swallow nests either in isolated pairs or loose groups, in both natural and artificial cavities. Breeding can start as soon as early May, although this date is occurring earlier because of climate change, and it can end as late as July. This bird is generally socially monogamous (although about 8% of males are polygynous), with high levels of extra-pair paternity. This can benefit the male, but since the female controls copulation, the lack of resolution on how this behaviour benefits females makes the high level of extra-pair paternity puzzling. The female incubates the clutch of two to eight (but usually four to seven) pure white eggs for around 14 to 15 days. The chicks hatch slightly asynchronously, allowing the female to prioritize which chicks to feed in times of food shortage. They generally fledge about 18 to 22 days after hatching. The tree swallow is sometimes considered a model organism, due to the large amount of research done on it.
An aerial insectivore, the tree swallow forages both alone and in groups, eating mostly insects, in addition to molluscs, spiders, and fruit. The nestlings, like the adult, primarily eat insects, fed to it by both sexes. This swallow is vulnerable to parasites, but, when on nestlings, these do little damage. The effect of disease can become stronger as a tree swallow gets older, as some parts of the immune system decline with age. Acquired T cell-mediated immunity, for example, decreases with age, whereas both innate and acquired humoral immunity do not. Because of its large range and stable population, the tree swallow is considered to be least concern by the International Union for Conservation of Nature. In the US, it is protected by the Migratory Bird Treaty Act of 1918, and in Canada by the Migratory Birds Convention Act. This swallow is negatively affected by human activities, such as the clearing of forests; acidified lakes can force a breeding tree swallow to go long distances to find calcium-rich food items to feed to its chicks.


The tree swallow was described as Hirundo bicolor by Louis Pierre Vieillot in his Histoire naturelle des oiseaux de l'Amérique Septentrionale, published in 1807. It was then placed in its current genus Tachycineta when Jean Cabanis established it in 1850. In 1878, Elliott Coues suggested that the tree swallow, at the very least, be put in its own subgenus, Iridoprocne, on the basis of its plumage, along with the white-winged swallow, Chilean swallow, white-rumped swallow, and mangrove swallow. By 1882, he had upgraded this to a full genus. Some authors continued to use this classification, with the addition of Tumbes swallow; however, genetic evidence supports the existence of a single genus, Tachycineta. The tree swallow is also called the white-bellied swallow for its white underparts.
The generally accepted genus name is from Ancient Greek takhykinetos, "moving quickly", and the specific bicolor is Latin and means "two-coloured". The other genus name, Iridoprocne, comes from the Greek iris, meaning rainbow, and Procne, a figure who supposedly turned into a swallow.
How exactly the tree swallow is related to other members of Tachycineta is unresolved. In studies based on mitochondrial DNA, it was placed basal (meaning it was the first offshoot in the species tree) within the North American-Caribbean clade consisting of the violet-green swallow, golden swallow, and Bahama swallow. Although mitochondrial DNA is advocated as a better indicator of evolutionary changes because it evolves quickly, analyses based on it can suffer because it is only inherited from the mother, making it worse than nuclear DNA from multiple loci at representing the phylogeny of a whole group. A study based on such nuclear DNA placed the tree swallow in the most basal position within Tachycineta as a whole (as a sister group to the rest of the genus).


The tree swallow has a length between about 12 and 14 cm (4.7 and 5.5 in) and a weight of approximately 17 to 25.5 g (0.60 to 0.90 oz). Wingspan ranges from 30 to 35 cm (12 to 14 in). The male has mostly glossy blue-green upperparts, the wings and tail being blackish. The underparts and the cheek patch are white, although the underwing coverts are grey-brown. The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is duller in colour than the male, and sometimes has a brown forehead. The second-year female also has brown upperparts, with a variable number of blue feathers; some third-year females also retain a portion of this subadult plumage. According to a 1987 study, this likely allows a younger female to explore nest sites, as the resident male is usually less aggressive to a subadult female. A 2013 study found that the resident female was less aggressive towards second-year female models when they were presented separately from older models. Why the female eventually replaces its subadult plumage is unknown; it may allow males to assess female quality, as pairs mate assortatively based on plumage brightness. The juvenile tree swallow can be distinguished by its brown upperparts and grey-brown-washed breast.


The tree swallow's song consists of three parts: the chirp, the whine, and the gurgle. These sections may be repeated or omitted, and all can stand alone. The first, as the chirp call (sometimes divided into the contact call and solicitation call), is made by the female during copulation and in both sexes to stimulate the nestlings to beg or (in some populations) when their mate leaves or enters the nest cavity. The whine, generally consisting of a downward shift in frequency followed by an upward shift, may be given alone as the anxiety call, occasionally made in response to certain predators. The gurgle, as when it appears at the end of the song, is usually uttered twice. It is likely involved in pair bonding. The chatter call is used to advertise nest sites (the reason it is also known as the "nest-site advertising call") and is also given to intruding conspecifics. A short high-pitched submission call is sometimes uttered after an aggressive encounter with another tree swallow. While being physically restrained or in pain, a distress call may be given. The male often utters a ticking (or rasping) aggression call during copulation, and both sexes use it at the end of mobbing dives. The alarm call is given in reaction to predators and other intruders, and can serve to induce older nestlings to crouch and stop begging when a predator is near.
Communication between parents and offspring can be disrupted by human-generated noise. A 2014 study, for example, found that broods for whom white noise was played were less likely to crouch or stop begging in response to alarm calls. Parents did not alter their calls to compensate, likely increasing predation risk. Noise can also disrupt whether parents respond to begging, but this may be balanced out by the louder calls nestlings give when exposed to it. Increased begging effort, however, may be ineffective or costly for louder levels of noise.


The tree swallow breeds in North America. Its range extends to north-central Alaska and up to the tree line in Canada. It is found as far south as Tennessee in the eastern part of its range, California and New Mexico in the west, and Kansas in the centre. It occasionally breeds further south in the US, and vagrants are sometimes found in the Arctic Circle, the northern Pacific, Greenland, and Europe. The wintering range is from California and southwestern Arizona in the west and southeastern Virginia in the east south along the Gulf Coast to the West Indies, Panama, and the northwestern South American coast. While migrating, this swallow often uses stop-over sites, spending an average of 57 days at these areas during autumn. To get to its wintering range, it often uses one of three flyways: the Western flyway, west of the Rocky Mountains; the Central flyway, between the Rocky Mountains and the Great Lakes, stretching south into Eastern Mexico; and the Eastern flyway, from the Great Lakes east. When a swallow returns to nest, it usually does not change breeding sites.
The breeding habitat of this bird is primarily in open and wooded areas, especially those near water. It roosts every night during the non-breeding season, preferring to rest in cane or reed beds over water, but it is also found over land and on trees and wires. Roosting sites are generally 100 to 150 kilometres (62 to 93 mi) apart.


Because of the large amount of research on the tree swallow and how it willingly breeds in nest boxes, biologist Jason Jones recommended that it be considered a model organism. Although it is aggressive during the breeding season, this swallow is sociable outside of it, forming flocks sometimes numbering thousands of birds.


The tree swallow nests in structures with pre-existing holes, both natural and artificial. These were once found only in forested regions, but the building of nest boxes has allowed this bird to expand into open habitats. This swallow usually nests in the area it bred the year before; only about 14% of females and 4% of males disperse to breed at a new site per year. Most do not go far, usually breeding at sites less than 10 kilometres (6.2 mi) away from their original grounds. Dispersal is influenced by breeding success; of the adult females that fail to fledge a chick, about 28% disperse, compared to 5% of successful breeders. Natal dispersal (when a bird does not return to the site it was born at to breed) is common in the tree swallow and occurs more frequently than breeding dispersal. It nests both in loose groups and isolated pairs. When nesting in loose groups, nests are usually spaced at least 10 to 15 metres (33 to 49 ft) apart, and those that are closer in distance are usually further apart in terms of laying date. In natural cavities, the tree swallow nests about 27 metres (89 ft) apart from its neighbor. The nest hole in these situations is, on average, 3.4 metres (11 ft) above ground level, although about 45% of them are less than 2 metres (6.6 ft) above the ground. Higher cavities are likely favoured because they reduce predation, while lower nest holes may be chosen to avoid competition. Entrance widths are often between 4 and 5 centimetres (1.6 and 2.0 in), whereas entrance heights are more variable: a 1989 study found openings ranging from 3.5 to 26 centimetres (1.4 to 10.2 in). Cavity volume is generally below 1,000 cm³ (61 cu in). After finding a suitable place to nest, the male perches near it and calls frequently. A lack of sites can cause fights between birds, sometimes resulting in deaths. This swallow usually defends an area around the nest with a radius of about 4.6 metres (15 ft), as well as extra nests inside of that territory, by blocking the entrance to the nest and chasing intruders. The nest cup itself is made from grass, moss, pine needles, and aquatic plants collected mostly by the female, and is lined with feathers gathered primarily by the male in fights. The feathers may function to insulate the nest, decreasing incubation time and likely preventing hypothermia in chicks. In addition to faster growth for chicks, eggs cool slower in nests with feathers than those without. However, a study published in 2018 did not find a significant correlation between the number of feathers in nests that were artificially warmed versus those that were not. Additionally, it found that nests in St. Denis, Saskatchewan used significantly less feathers than those in Annapolis Valley, despite the former being further north. However, temperatures in Nova Scotia (where Annapolis Valley is) are generally lower than those in Saskatchewan, possibly explaining the unexpected result.
During courtship, a male tree swallow attacks an unknown female. This can be stimulated through wing-fluttering flight by the female, which may be an invitation to court. The male may then take a vertical posture, with a raised and slightly spread tail and wings flicked and slightly drooped. This prompts the female to try to land on the male's back, but he flies to prevent this; this is repeated. After courting the female, the male flies to his chosen nest site, which the female inspects. During copulation, the male hovers over the female, and then mounts her, giving ticking calls. He then makes cloacal contact with the female while holding her neck feathers in his bill and standing on her slightly outstretched wings. Copulation occurs multiple times.
Eggs are laid from early May to mid-June (although this is happening earlier due to climate change) and chicks fledge between mid-June and July. Latitude is positively correlated with laying date, while female age and wing length (longer wings allow more efficient foraging) are negatively correlated. The tree swallow is likely an income breeder, as it breeds based on food abundance and temperatures during the laying season. This species is generally socially monogamous, but up to 8% of breeding males are polygynous. Polygyny is influenced by territory: males having territories with nest boxes at least 5 metres (16 ft) apart are more likely to be polygynous. It is suggested that this polygyny depends on the conditions during the laying season: better conditions, such as an abundance of food, allow females in polygyny who do not receive help foraging to lay more eggs.
The tree swallow has high rates of extra-pair paternity, 38% to 69% of nestlings being a product of extra-pair paternity, and 50% to 87% of broods containing at least one nestling that was the result of an extra-pair copulation. One factor that might contribute to this is that females have control over copulation, making paternity guards ineffective. This may be mitigated by more frequent copulations just before egg laying, according to a 2009 study which found that within-pair copulation attempts peaked three to one days before the first egg was laid and that more successful attempts during this period increased the share of within-pair young males had. This latter finding contradicts those of a 1993 and a 1994 study. Extra-pair paternity does not change the level of parental care the male contributes in the tree swallow. A significant number of extra-pair fathers may be floaters (those present at breeding grounds that presumably do not breed). A 2001 study found that out of 35 extra-pair nestlings, 25 were sired by local residents, three by residents of nearby sites, and seven by male floaters. In the tree swallow, floating thus helps males in good condition produce more chicks, while allowing males in bad condition to be successful by investing in parental care. There is also a significant population of female floaters; a 1985 study estimated that around 23% to 27% of females were floaters, of which about 47% to 79% were subadults.
Why females engage in extra-pair copulation and how they choose extra-pair mates is controversial. One theory, called the genetic compatibility hypothesis, states that increased offspring fitness results from increased heterozygosity, and thus that female tree swallows would prefer to mate with males that are less genetically similar to them. Females may also choose sperm after copulation to ensure a compatible mate. In support of this theory, a 2007 study found that extra-pair offspring were more heterozygous than within-pair offspring. However, a 2005 paper discovered a slight negative correlation between a pair's genetic similarity and the proportion of extra-pair young in their nest. The good genes theory says that females choose extra-pair males based on the quality of their genes. This would explain why some tree swallows do not have any extra-pair young, whereas others do. However, most studies have not found phenotypic differences between extra-pair and within-pair males (although a 2007 study did find that older males with brighter plumage were more likely to mate outside of the pair bond). Additionally, according to a 2017 thesis, extra-pair offspring are no more likely to join their natal population than within-pair offspring. Another theory suggests that extra-pair paternity is context dependent, with extra-pair young outperforming within-pair young in certain situations, and underperforming in other environments. A 2017 dissertation, for example, found that extra-pair young were larger, heavier, and longer-winged than within-pair young when both were exposed to predator mounts, while within-pair young were heavier than extra-pair young when they were shown non-predator mounts. This thesis also found that within-pair young outperformed extra-pair young in terms of life-time fitness when they were raised in less-variable environments, suggesting that extra-pair offspring have less developmental plasticity than within-pair offspring. A 2018 study weakly supported this context dependent hypothesis, finding that extra-pair offspring were more likely to fledge than within-pair offspring in experimentally enlarged broods; however, neither telomere length (a correlate of survival and reproductive success) nor size 12 days after hatching were significantly different among these young, and no significant differences between the two types were found in non-enlarged broods.
Studies attempting to prove the adaptability of extra-pair paternity for females have been criticized for the lack of positive effect that increased offspring fitness would have when compared with the potential cost of decreased fitness for the female, such as increased predation from searching for mates. Thus, theories based on the non-adaptivity of extra-pair paternity for females have been postulated. These theories are based on genetic constraint, where an allele resulting in a maladaptive behaviour is maintained because it also contributes to a beneficial phenotype. The theory of intersexual antagonistic pleiotropy says that strong selection for extra-pair paternity in males (as seen in this bird) overrides the weak selection against extra-pair paternity in females. The hypothesis of intrasexual antagonistic pleiotropy, meanwhile, argues that extra-pair paternity is present because the genes regulating it have pleiotropic effects on aspects of female fitness, like within-pair copulation rate.
The tree swallow lays a clutch of two to eight, although usually four to seven, pure white, and translucent at laying, eggs that measure about 19 by 14 mm (0.75 by 0.55 in). These eggs are incubated by the female, usually after the second-to-last egg is laid, for 11 to 20 days, although most hatch after 14 to 15 days. About 88% of nests produce at least one nestling, but this can be lowered by poor weather and a younger breeding female. The eggs generally hatch in the order they were laid. They also hatch slightly asynchronously, with an average of 28 hours between when the first and final nestling emerges. This can result in a weight hierarchy where earlier-hatched chicks weigh more (especially early in the nestling period) than those hatched later, allowing the female to prioritize which chick to give food to during food shortages. This likely has its greatest effect early in the nestling period, as by 12 days after hatching, there are generally no significant weight differences. Infanticide of the chicks and eggs sometimes occurs when a male is replaced by another male. Infanticide usually does not occur when the clutch is not complete, as replacement males then have a chance to fertilize at least one egg. When the male arrives during incubation, it sometimes commits infanticide, but other times adopts the eggs, as there is a chance that some eggs were sired from the replacement male. If the replacement male arrives after the chicks hatch, infanticide is usually committed, though the female will sometimes prevent this.
Nests produced by females of better condition often have sex ratios skewed towards high quality males. A 2000 study hypothesized this to be because males have more variable reproductive success, and therefore that a high quality male produces more offspring than a female of similar quality.
The growth and survival of nestling tree swallows is influenced by their environment. In both younger and older nestlings (those between two and four days old and between nine and eleven days, respectively) growth is positively influenced by a higher maximum temperature, particularly in the former. A later hatching date negatively impacts growth, especially for younger nestlings. Older chicks grow somewhat faster when insects are abundant. Growth in younger nestlings increases with age, while in old nestlings, it decreases as they get older. Young tree swallows are able to thermoregulate at least 75% as effectively as the adult at an average age of 9.5 days when out of the nest, and from four to eight days old when in the nest (depending on the size of the brood). The nestlings fledge after about 18 to 22 days, with about 80% fledging success. Like hatching success, this is negatively affected by unfavourable weather and a younger female. Chicks may be preyed on by snakes and raccoons. This predation can be exacerbated by begging calls.


The tree swallow forages up to 50 metres (160 ft) above the ground singly or in groups. Its flight is a mix of flapping and gliding. During the breeding season, this is mostly within 4 kilometres (2.5 mi) of the nest site. When it is foraging for nestlings, though, it usually goes up to 200 metres (660 ft) from the nest, mostly staying in sight of it, and forages at a height up to 12 metres (39 ft). As well as being caught in flight, insects are sometimes taken from the ground, water, vegetation, and vertical surfaces.
The tree swallow eats mostly insects, with some molluscs, spiders, and fruit. In North America, flies make up about 40% of the diet, supplemented with beetles and ants. Otherwise, the diet is about 90% flies. The insects taken are a mix of aquatic and terrestrial organisms; the former are an important source of omega-3 highly unsaturated fatty acids. This is because, although the tree swallow can convert the precursor α-Linolenic acid into highly unsaturated fatty acids like docosahexaenoic acid, it cannot do so in the quantities needed. The seed and berry food is mainly from the genus Myrica, which is mainly taken in all four of the Northern Hemisphere seasons except summer. Crustaceans were also found to be important in the wintering diet in a study on Long Island, New York.
Both sexes feed the nestlings (although the male feeds the chicks less than the females) resulting in about 10 to 20 feedings per hour. The parents often use the chirp call to stimulate nestlings to beg. This is used more frequently with younger chicks, as they beg less than older chicks when the parent arrives with food but does not call. The likelihood of begging in the absence of parents also increases with age. The hatching order affects how much a chick is fed; last-hatched nestlings (in cases where hatching is asynchronous) are likely fed less than those hatched earlier. Nestlings closer to the entrance of the nest are also more likely to be fed, as are those who beg first and more frequently. The overall rate at which a brood is fed also increases with more begging. The diet itself is composed mostly of insects, those in the orders Diptera, Hemiptera, and Odonata making up most of the diet. These insects are mostly up to 10 mm (0.39 in) in size, but sometimes are up to 60 mm (2.4 in) in length. In nests near lakes acidified by humans, calcium supplements, primarily fish bones, crayfish exoskeletons, clam shells, and the shells of bird eggs, are harder to find. This forces the adult tree swallow to travel further than usual—sometimes up to 650 m (2,130 ft) away from the nest—to get these calcium supplements.


The tree swallow has an average lifespan of 2.7 years and a maximum of 12 years. About 79% of individuals do not survive their first year, and those that do face an annual mortality rate of 40% to 60%. Most deaths are likely the result of cold weather, which reduces insect availability, leading to starvation. Lifespan is associated with telomere length: a 2005 study that used return rates (to the breeding site of the previous year) as a proxy for survival found that those with the longest telomeres at one year of age had a predicted lifespan of 3.5 years, compared to the 1.2 years for those with the shortest telomeres. Whether short telomeres cause a reduction in fitness or are simply an indicator of it is unknown. Regardless, a 2016 thesis found that measures of condition were positively correlated with telomere length. Males also generally had longer telomeres than females, as did smaller-winged birds. Individuals with shorter telomeres may compensate for potential losses in fitness by increasing reproductive effort, whereas those with longer telomeres may decrease their investment, as evidenced by the smaller proportion of chicks females with longer telomeres fledged. Telomere length is highly heritable, and is especially dependent on that of the mother.


The tree swallow is susceptible to a wide range of predators. Eggs, nestlings, and adults in the nest fall victim to black rat snakes, American crows, American kestrels, common grackles, northern flickers, chipmunks, deermice, domestic cats, weasels, American black bears, and raccoons. While flying or perched, predators to the tree swallow include American kestrels, black-billed magpies, barred owls, great horned owls, merlins, peregrine falcons, and sharp-shinned hawks. Whilst evasive flight is the usual response to predators in free-flying swallows, mobbing behavior is common around the nest, and is directed not just towards predators, but also towards nest site competitors, who might be scared off by it. This behaviour involves the swallow swarming and diving towards (but not actually striking) the intruder from around 5 to 20 m (16 to 66 ft) above the ground, usually giving soft ticking calls near the end and coming within about 0.5 to 2 m (1.6 to 6.6 ft) of the predator. It seems to alter the intensity of its attacks based on which predator approaches; a 1992 study found that ferrets elicited a more vigorous defence than black rat snakes, and a 2019 thesis similarly discovered that black rat snake models were dived at the least and eastern chipmunk models the most. It is suggested that the snake prompted a weaker response because defence behaviours may be less effective and more dangerous to perform against it.


The tree swallow is vulnerable to various parasites, such as the blood parasite Trypanosoma. It is also susceptible to the flea Ceratophyllus idius and the feather mites Pteronyssoides tyrrelli, Trouessartia, and (likely) Hemialges. It is also probably afflicted by lice of the genera Brueelia and Myrsidea. There is a correlation between the number of fleas on a bird and the number of young it is caring for. This relationship is speculated to arise from an improved microclimate for fleas due to a larger clutch. Nestlings also suffer from parasites, like blow-flies of the genus Protocalliphora, which results in a loss of blood by nestlings. These parasites, though, are found in a majority of nests and do not seem to have a large effect on nestlings. A study published in 1992 found that the effects of blow-fly parasitism explained only about 5.5% of the variation in nestling mass.


In the breeding female tree swallow, humoral immunocompetence (HIC) is inversely correlated with laying date. This means that, on average, a bird that lays its eggs earlier has a stronger antibiotic response to an antigen than a bird that lays later. A tree swallow that is handicapped by wing-clipping generally has a lower HIC. These relationships could be interpreted as supporting the conclusion that a female that lays earlier acquires a higher HIC, but the authors of the study that found the correlations believed this unlikely, due to the colder temperatures near the start of the breeding season. Instead, they thought that HIC could be a measure of quality, and that a higher quality female is able to lay earlier. The authors also postulated that it is an indicator of workload, as shown by the lower HIC of handicapped birds.
Higher quality female tree swallows (as measured by laying date) are able to maintain their reproductive effort while diverting resources to fight an immune challenge. Lower quality swallows are less able to do so; a 2005 study in Ithaca, New York, found that late-laying females with an artificially enlarged brood, although able to maintain offspring quality, had lower responses to an immune challenge than those that were of higher quality or did not have an enlarged brood. Whether a female chooses to prioritize offspring quality or immunocompetence is likely related to survival probabilities; a 2005 study discovered that females with an enlarged brood in Alaska, where survival rates are lower, had weaker immune responses, but kept reproductive effort steady, whereas those in Tennessee, with higher survival rates, had a stronger response but lower quality offspring.
In the tree swallow, some components of the immune system deteriorate with age. Acquired T cell-mediated immunity, for example, declines with age in the female tree swallow. But, the age of a female does not affect both the acquired and innate humoral immunity; the lack of deterioration in the former contrasts with studies on barn swallows and female collared flycatchers. Because of this immunosenescence (a decrease in immune function with age), older females infected with a disease generally visit their nest less, resulting in their nestlings growing slower. They are also likely to lose weight because of an infection.


The tree swallow is considered to be least concern by the International Union for Conservation of Nature. This is due to the bird's large range of about 834,000 km² (322,000 sq mi), and its stable population, estimated to be about 20,000,000 individuals. It is protected in the US by the Migratory Bird Treaty Act of 1918, and in Canada by the Migratory Birds Convention Act. In some parts of the US, the range of this swallow has extended south, likely due to changes in land use, the reintroduction of beavers, and nest boxes installed for bluebirds. The tree swallow is negatively impacted by the clearing of forests and the reduction of marshes, the latter reducing the habitat available for wintering. This swallow has to compete for nest sites with the common starling, house sparrow (both introduced to North America), bluebirds, and the house wren (which also destroys nests without occupying them). Acidification of lakes can force this swallow to go relatively long distances to find calcium-rich items, and can result in chicks eating plastic. Other chemicals, like pesticides and other pollutants, can become highly concentrated in eggs, and PCBs are associated with the abandonment of a pair's clutch. Contamination from oil sands mine sites can negatively affect tree swallows by increasing the presence of toxins, as measured by the activity of ethoxyresorufin-o-deethylase (a detoxification enzyme) in nestlings. This normally has little influence on nestling and fledging, though extreme weather can reveal the effects: a 2006 study found that nestlings from wetlands most polluted by oil sands processing material were more than 10 times more likely to die than those from a control site during periods of synchronized cold temperatures and heavy rainfall, compared to the lack of difference in mortality between the groups when the weather was less extreme. A 2019 paper, however, found that increased precipitation caused a similar decline in hatching and nestling success for nestlings both near and far from oil sands sites. In another study, birds exposed to mercury fledged, on average, one less chick than those not, an effect amplified by warm weather. In addition, cold weather events can rapidly reduce the availability of aerial insect prey, and in some populations with advancing reproduction may result in reduced offspring survival.


The violet-green swallow (Tachycineta thalassina) is a small North American passerine bird in the swallow family. These aerial insectivores are distributed along the west coast from Alaska to Mexico, extending as far east as Montana and Texas. With an appearance very similar to the tree swallow, these individuals can be identified by the white rump side-patches that appear to separate their green back and purple tail. Violet-green swallows are secondary cavity nesters, found in a number of habitats including deciduous and coniferous forest. In addition to nesting in tree holes within these habitats, they are also widely observed nesting in the cracks of large cliffs.


The distinct body form of swallows distinguishes them from other passerine birds. Their long pointed wings and slim, streamlined body evolved to catch insects while in flight. The body of the violet-green swallow is no exception. With an average body length of 5¼ in. (13 cm), the violet-green swallow is slightly shorter and appears more compact in flight compared to other members of the family Hirundinidae. The violet-green swallow most closely resembles the North American tree swallow, but can be distinguished by its shorter wings and colouration.


The violet-green swallow gets its name from the colouration on its back and rump. The species is best identified by the glossy green on the top of the head and back as well as hints of purple on the nape, rump and upper tail. Below the green back, the remainder of the wing is a grayish-bronze. Similar to other swallows, T. thalassina is white below, but differs in that the white continues onto rump side-patches that almost meet at the base of the tail. These white rump side-patches sometimes look like one continuous stripe when in flight. White also extends onto the cheeks, partially surrounding the eye. The notch in the tail of the violet-green swallow is slightly shallower than that of the tree swallow, but deeper than the relatively flat tail of the cliff swallow.
Violet-green swallows exhibit very little sexual dimorphism, with adult males simply showing brighter colours than adult females. Additionally, the white cheeks are not as prominent and the head is more bronze than green on the female. Juveniles are not as easily identifiable compared to adults due to their dull colouration. Similar to other juvenile swallows, especially the tree swallow, the juvenile violet-green swallow is white below and grayish-brown above. However, the more gradual change in colour and visible (but slightly reduced) white cheek patches can help identify juvenile individuals of the species.


The swallows have been well studied ecologically, but only recently has their phylogeny been thoroughly researched. Swallows are passerine birds grouped within the family Hirundinidae. The family Hirundinidae is split into two subfamilies: Pseudochelidoninae, which contains two species of river martins, and Hirundininae, comprising all other martins and swallows. The 82 species within the subfamily Hirundininae are further classified into three groupings: the mud nesters, basal relicts and core martins, with the violet-green swallow falling into the last group. Violet-green swallows are one of 9 species of New World tree swallows within the genus Tachycineta. This genus is a monophyletic group and is considered the sister taxa of all other New World swallows.
Violet-green swallows are important members of the Tachycineta clade due to their large geographic range and because they are one of 2 species that breed within North America. It is generally agreed that Tachycineta is split into a North and a South American clade, but the phylogenetic placement within the genus depends on the type of analysis used. The violet-green swallow is a member of the North American grouping, along with T. bicolor (the North American tree swallow), T. euchrysea (the golden swallow of Hispaniola and Jamaica) and T. cyaneoviridis (the Bahama swallow). A mitochondrial genome analysis has placed T. thalassina as a sister taxon of the Caribbean swallows, T. euchrysea and T. cyaneoviridis, with all 3 species forming a sister clade to T. bicolor. Nuclear genome analyses and a consensus of both methods have reorganized this North American clade, alternating the closest sister taxon of T. thalassina between T. cyaneoviridis and T. euchrysea. Nonetheless, the taxonomy of the violet-green swallow is well understood up to the genus level, after which some uncertainty surrounds the placement of T. thalassina within the North American clade of the genus Tachycineta.


Violet-green swallows are divided into three subspecies, T. t. thalassina, T. t. brachyptera and T. t. lepida differing in breeding ranges and wing length. T. t. thalassina has slightly longer wings and has been known to breed as far north as Alaska, while the shorter winged T. t. brachyptera breeds further south in California and Mexico. Not all of the literature agrees upon T. t. lepida as a third subspecies, and little information is available to help distinguish it from other subspecies.


Hybridization has been known to occur among the swallows, with a few cases involving violet-green swallows being reported. Breeding between violet-green swallows and both tree and barn swallows has been recorded on separate occasions, but resulting offspring were not observed. In 2000, the strange plumage of a swallow seen in British Columbia, Canada, suggested the possible successful hybridization of a violet-green and a cliff swallow. Nonetheless, these observations are rare, which accounts for the minimal research into swallow hybridization.
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The type of habitat occupied by violet-green swallows varies depending on their geographical location and elevation. Across their range, these birds can be found in deciduous, coniferous and mixed forests, as well as within canyons and in close proximity to large cliffs. Breeding and non-breeding habitats do not differ much except that breeding habitat is usually at lower elevations. Violet-green swallows have also been observed nesting around buildings in more settled areas.


Violet-green swallows are a predominantly western species, with the rare sighting of individuals in eastern North America. The distribution of the species can be divided on the basis of the recognized subspecies, but the entire range spans from central Alaska down to Mexico. Longitudinally, the range borders the west coast of Alaska, British Columbia and the United States, and extends eastward into southwestern Alberta, Montana, the Dakotas and Texas. The breeding range spans almost the entire distribution, while the winter range is restricted to Mexico.


There are many knowledge gaps surrounding the vocalization behaviour of violet-green swallows. These gaps include vocalizations made during early development, alarm calls and the daily pattern of calls. The little information available suggests two main classes of vocalizations, the chee-chee calls and twitter calls.


This call is most commonly heard when one violet-green swallow interacts with another swallow, either during foraging, in-flight chases or when approaching a nesting site. Flocks of swallows have been recorded making chee-chee calls, suggesting its use in social cohesion. Juveniles have also been observed making this vocalization when waiting to be fed by an adult, implying that it plays a role in parent-juvenile recognition.


Observations of violet-green swallows making twitter calls typically associate the vocalization with courtship displays and the establishment of new territories. Twitter calls have only been heard in flight, either by a male escorting a female or during brief intraspecific territorial disputes. Mixing of the two calls occurs occasionally, but little ecological research can explain its use.


Similar to other swallows, violet-green swallows are specialized aerial insectivores, catching and eating their prey while in flight. However, they have been known to feed higher in the sky than most other swallows. The examination of the stomach contents of multiple individuals has presented a wide range of diet items, including insects like ants, beetles and flies as well as other arthropods such as spiders.  On rare occurrences these birds have been observed foraging along the ground, but such events represent exceptions to their typical feeding habits.


Violet-green swallows will usually arrive at their breeding area weeks prior to the start of reproduction. Location dependent, copulation takes place mid-May with the eggs being laid by the start of June, followed by a couple weeks of incubation before hatching. The average clutch size is 5 eggs, with females laying approximately 1 per day. During the weeks post-hatching, the parents feed their young as they slowly begin to grow their feathers. After approximately 3 weeks the young are ready to leave the nest. It is more common for pairs to reproduce once per breeding season, but a second brooding has been observed on occasion.


Violet-green swallows are secondary cavity nesters, meaning they typically nest in natural holes or previously occupied nests. Some breeding pairs will even go as far as usurping nests from other species. A majority of violet-green swallow nests are in tree holes excavated by other animals or within the cracks of large cliffs. Due to their dependence on large trees, violet-green swallows are highly impacted by forest management practices. In addition to nesting in natural cavities, violet-green swallows have also been observed occupying artificial nest boxes. Pairs typically breed in independent nests, except on cliffs where large colonies can be found nesting together.


Violet-green swallows have been observed cooperating and competing with various avian species, including western bluebirds. A similar field observation notes a violet-green swallow laying an egg in an active bluebird nest box. Initially, the male bluebird attempted to drive the swallow from the nest cavity, while the female bluebird did not seem concerned with the intruder. It appeared the bluebirds tolerated the act of egg-dumping by the violet-green swallow, but the observer returned the following day to find the newly laid egg smashed below the nest. This behaviour suggests that when unable to access her original nest after physiologically committing to laying her egg, a female violet-green swallow may participate in interspecific egg-dumping.


Violet-green swallows are secondary cavity nesters and aerial insectivores, making males susceptible to nest and mate competition. To avoid being cuckolded, males spend more time guarding their mate than their nest, contrary to tree swallows. This paternity-defence behaviour emphasizes that non-territorial violet-green swallows exhibit greater mate competition than nesting site competition.


Multiple accounts of violet-green swallows forming cooperative relationships with other species have been recorded. From 1981 to 1982, three independent swallow pairs were observed co-occupying the nest boxes of western bluebirds. These violet-green swallows protected the nesting site, removed fecal sacs from the boxes and fed the bluebird fledglings with no resistance from the adult western bluebirds. Despite too small of a sample size to hold statistical significance, fledgling survival was greater when violet-green swallows provided active care. It is believed that the swallows benefit from the cooperative relationship by inheriting the nest box after the bluebird parents and fledglings have left.


Similar to the occasional observation of violet-green swallows building interspecific cooperative relationships, they have also been involved in interspecific competition for nesting sites. One example from 1974 noted the competitive behaviour between mountain chickadees and violet-green swallows. The physical altercation began when a pair of swallows attempted to overtake a nesting site occupied by a pair of chickadees and their fledglings. After multiple aerial battles, the chickadees regained control of their nest and successfully defended against future violet-green swallow attacks. The same field observer noted a similar altercation between violet-green swallows and hairy woodpeckers, which resulted in the same outcome. These species are permanent residents, allowing them first choice of nesting sites, while the violet-green swallows are summer residents with late breeding habits. Thus, a scarcity of viable nesting sites may lead to this interspecific competitive behaviour in violet-green swallows. A similar observation of competitive behaviour for potential nesting sites has been observed between acorn woodpeckers and violet-green swallows.


It has been speculated that certain birds, including swallows, enter a state of torpidity during harsh winter conditions. Few observations of this decrease in body temperature and metabolic rate have been recorded in violet-green swallows, the first case occurring in 1965 near Death Valley National Monument in Saratoga Springs, California. Field observers noted 3 “dead” individuals on the east-facing slope of a dune the morning after a cold and windy night. Upon closer observation, the violet-green swallows made minor movements, such as opening their eyes, but did not struggle while being handled. The physical appearance of the swallows, including the position of their head in relation to the slope and the fluffing of their feathers was similar to that of other birds in torpor. Despite the lack of thermometers, it was apparent these 3 individuals were in a state of hypothermia for about 45 minutes after the sun began to rise. Eventually the 3 swallows awkwardly flew off, signifying the end of their torpor bout.


In addition to reaching borderline hypothermic temperatures during bouts of torpor, violet-green swallows have been observed behaving similar to hyperthermic individuals while sunbathing. Indications of this activity include the orientation of their wings and tail, their trance-like state and the occasional loss of balance. Research has shown that increasing feather temperatures during basking can control ectoparasites. The period of sunbathing in violet-green swallows is short and dependent on ambient temperature and wind velocity, but typically occurs after an increase in parasite loads near the end of nesting.


The Australian shelduck (Tadorna tadornoides), also known as the chestnut-breasted shelduck or mountain duck, is a shelduck, a group of large goose-like ducks part of the bird family Anatidae. The genus name Tadorna comes from Celtic roots and means "pied waterfowl". They have a striking chestnut-coloured breast and black body. They are protected under the National Parks and Wildlife Act 1974.


William Jardine and Prideaux John Selby described the Australian shelduck in 1828.


The males are mostly dark, with a chestnut breast. They have white neck collars and dark green heads. The females are similar, but they have white around the eyes and are smaller. Both males and females have chestnut and black wings with a green speculum, and show some white on their wings during flight.
The downy young are white with a brown crown and brown stripes from crown to tail. Juvenile males are duller than the adults and also lack a white collar, while juvenile females have a lot more white on their excluding their crown.
The vocal calls of the male are a deep honk similar to a goose, while the female's call is a high pitched and penetrating "zeek, zeek".


The Australian shelduck mainly breeds in southern Australia and Tasmania and is still fairly common. In the winter, many birds move farther north than the breeding range. As with other shelducks, this species has favourite moulting grounds, such as Lake George, New South Wales, where sizeable concentrations occur. The Australian shelduck's primary habitat is lakes in fairly open country.


Australian Shelducks can be seen in flocks of up to 1000 or more. They are extremely wary of humans and will often call in their presence, but they can get used to people in urban areas. They are upright on land when grazing, and in the water where they sit high. Young birds dive frequently, but adult birds only dive during moulting when they are flightless, or when they are injured or scared.


Australian Shelducks often make their nests in tree holes lined with down, holes in banks, or similar locations. Eight to fifteen eggs are laid, and incubated for between thirty and thirty-three days. After leaving the nesting hollow, the downy and flightless young often aggregate in crèches of 20-40 birds, and even up to 100 birds rarely.


Australian Shelducks feed by grazing, dabbling and filtering. The eat tubers and other plant material, such as saltbush and samphire, along with a range of insects, crustaceans and molluscs.


Taenidia integerrima, the  yellow pimpernel, is an herbaceous plant in the parsley family. It is native to the eastern North America, where it is widespread. Its natural habitat is rocky prairies and woodlands, often over calcareous substrates. It is a perennial.


It is listed as endangered in Connecticut, as historical in Rhode Island, and threatened in Vermont.


The Menominee  take an infusion of root taken for pulmonary troubles, chew the steeped root for 'bronchial affections', and use it as a seasoner for other remedies because of the good smell. The Ojibwe smoke the seeds in a pipe before hunting for good luck.


Taeniopoda eques, the western horse lubber grasshopper, is a relatively large grasshopper species of the family Romaleidae found in the arid lower Sonoran life zone of the southwestern United States and northern Mexico. Northern populations are identifiable by their shiny black bodies and black and yellow reticulated forewings. Some southern populations are yellow in the adult stage. The species is unique in using its black coloration to thermoregulate and in being chemically defended. The aposematic coloration warns vertebrate predators of its unpalatability and allows the grasshopper to roost conspicuously upon desert shrubs.


T. eques was first described by Hermann Burmeister in 1838. The vernacular lubber refers to the flightless terrestrial status of the subfamily Romaleinae. Eques is the Latin term for "horseman".


T. eques is one of the largest grasshopper species in North America. A female of the species can reach 7 centimeters in length and weigh 9 grams. The mature male weighs 3 grams on average. There is a wide range of sizes due to influences in its specific habitat. Males stridulate more commonly than females by expanding the hindwings against the closed forewings, thus flashing the bright red hindwings. It is unique among desert grasshoppers because of its conspicuous size and coloring. The body is mostly black, with finely patterned black and yellow forewings with green veins and red hindwings with black borders. The antennae and head of the adult include orange markings. The forewings of males normally extend past the tip of the abdomen. However, most T. eques cannot fly, with only approximately 10 percent of males possessing wings long enough for flight. The T. eques nymph resembles the adult in coloration, except the nymph also possesses yellow head markings and black antennae.


T. eques ranges from southern Arizona, New Mexico, and Texas to central Mexico, and inhabits the lower Sonoran life zone, which consists primarily of sparse desert brush and grasslands. It can be found among Acacia, Mimosa, Ephedra, and Yucca shrubs. In the United States, this grasshopper species is the only member of its genus (Taeniopoda) and one of the largest arthropods. In the United States, it inhabits the Chihuahuan Desert community from southern Arizona to the Big Bend region of Texas. The Chihuahuan Desert receives a high amount of summer precipitation compared to other deserts, which is necessary for the grasshopper's development.


T. eques does not feed on the same plants it roosts on. In an experiment, it was found to be unable to survive on Acacia and Mimosa shrubs alone. It feeds mainly on foliage, flowers, and seed pods of low-growing summer desert annuals. T. eques only forages during daylight hours; at night it roosts near the tops of desert shrubs to hide from nocturnal ground predators. At dawn, it descends to the desert floor to feed on the annual plant species which are abundant following summer rains. T. eques drink free-standing water from raindrops. T. eques is known to be polyphagous, and also consumes a variety of other material, including spider silk and feces. It is an opportunistic carnivore and can occasionally be found scavenging for insect and vertebrate cadavers. It can detect odors to find mammal and insect carcasses, which may provide a source of protein and nitrogen in the diet. The female is more likely engage in scavenger behavior than the male T. eques. This difference may be explained by the female's greater need for protein and other nutrients to facilitate more rapid maturation and egg production. Cannibalism has been observed upon molting or incapacitated individuals of its own species.


T. eques is univoltine, producing only one brood of offspring per year. Females lay eggs at the base of shrubs or large rocks, depositing the approximately 50 eggs in a single pod 4-8 centimeters deep into the soil. The females also eject a liquid with the eggs, which dries and forms a hard case protecting the egg pod. In the United States, eggs are deposited in subterranean egg pods in October. The number of egg pods laid is dependent upon the rate of development in the adults and the time available before the frost sets in. The grasshoppers reach maturity in October and die in November during the winter freeze. Thermoregulation is necessary for speeding the development of T. eques to increase its reproductive chances before the favorable growing season ends.
Along with the onset of the summer rainy season, the young hatch in synchrony from subterranean egg pods in July. The larvae are especially vulnerable to predatory ants for about the first three minutes after hatching. After shedding the provisional cuticle, the larvae climb up the nearest vertical object. They are born reddish in color, but transform to black within two hours.
Despite its large size, T. eques has a relatively speedy rate of larval development, undergoing five nymphal molts to reach the adult stage in about 40 days. Recently molted individuals are brown but darken within two hours at warm temperatures. Temperature influences whether they can complete the molting process. At temperatures less than 25 °C, molting is usually not initiated. At temperatures above 36 °C, they can become stuck in old exoskeletons. Individuals are exposed to predation and sibling cannibalism during molting. T. eques is different from other aposematic grasshoppers in its asynchronous molting.
Mating begins about 12 days after maturity, and about 30 days after the adults molt, females begin laying egg pods each containing about 50 eggs. Egg pods are deposited 6 to 9 centimeters underground. Females continue to lay subsequent egg pods at 18-day intervals until they are killed by the freeze in November.


Thermoregulation is necessary for all essential life functions of T. eques and most other behaviors, including food consumption and digestion, predator escape, reproduction, walking, flying, and ovipositing. The desert environment of T. eques is often unpredictable and allows the grasshopper only about four months, the time between the onset of the summer rains and the arrival of the winter freeze, to complete its entire life cycle. Growth and development are further slowed by cold desert nights, and in October, cold days. T. eques speed development by solar basking, aided by its black heat-absorbing coloration. By thermoregulating, the grasshopper can maintain an optimal body temperature between 30 and 40 degrees Celsius for most of the day. Elevating body temperature for extended periods allows T. eques to metabolize faster, thus permitting maximum growth and reproduction before the onset of winter. Without thermoregulation, T. eques could not survive in its northern range.
The unique black coloration of T. eques is thermally beneficial, contributing to the species' shorter larval development compared to the light- colored desert grasshoppers. T. eques has also developed behavioral thermoregulatory mechanisms for sunlight exposure. Flanking occurs when the grasshopper orients its body perpendicular to sunlight, maximizing thoracic heat gain. The sun-side hindleg is lowered, the shade-side hindleg is raised, and the abdomen is lowered to reduce wing shading. Moving into the centers of bushes allows for shading to limit sun exposure at midday to prevent overheating.


Ants regularly attack hatching and molting nymphs. Vertebrates sharing the habitat of T. eques rarely disturb horse lubbers and prefer other lubber grasshopper species instead. Only invertebrates and grasshopper mice have been shown to be undeterred by adult T. eques defenses.
T. eques possesses a multi-sensory defense system. The chemical secretion has a strong coffee-vanilla odor and composed of a complex mixture of synthesized phenolics and plant toxins produced from the grasshopper's diet. When consumed, the toxic tissues of T. eques cause vomiting or death in predators. The species relies on a comprehensive aposematic display containing chemical deterrents, and visual and auditory elements for defense against vertebrate predators. For example, when attacked by mice, the grasshoppers spray the odorous secretion from their metathoracic spiracles while producing a hissing noise. The secretion surrounds the insect in a noxious deterrent cloud. Adults also turn sideways to predators and display their bright red hindwings while waving their bright antennae and spiny hindlegs in a threatening manner. Together these signals warn naïve predators and remind experienced predators of the grasshopper's toxicity.


In the first stage of life, pod mates aggregate and move and feed together, but disperse after a few days. Aggregation is tightest in this first-instar period and may be a method of defense for the vulnerable developing grasshoppers. Thereafter they are solitary, although mature T. eques are attracted to the largest bush at dusk which provides the appearance of clumping. This behavior may provide benefits of increasing opportunities for mating and enhancing aposematic displays against predators.


Both sexes of mature T. eques engage in promiscuous behavior. Males are sexually aggressive, actively mounting females and males of the species as well as individuals from other grasshopper and lizard species.
Males cautiously stalk females before suddenly mounting without any communicatory leg or wing signaling. Females react violently when mounted by jumping, kicking, running, and rotating from side to side.
However, immediately following copulation, females become docile and carry males on their backs. Males do not guard ovipositing females.
The female T. eques releases a pheromone that elicits male attraction and sexual behavior over a short distance. Male T. eques can remain in copulation for up to 24 hours, continuously passing spermatophores to the female.


Multiple phenotypic traits interact in T. eques since chemical defense from vertebrates releases the species from the need to be small and hidden. Thus T. eques has evolved a large body size, to increase fecundity, deter small invertebrate predators, increase water retention, and allow for deep ovipositing. However, the large adult size requires long development and growth, which is difficult in its short season. It speeds growth by thermoregulation mechanisms including dark color and solar exposure positions, both allowed only because of chemical defense. These features cause T. eques to be conspicuous; however, chemical deterrents protect it against predators. The species can allocate resources to reproduction instead of wings and flight muscles. As with many other chemically defended insects, T. eques is flightless and sluggish.


The double-barred finch (Stizoptera bichenovii) is an estrildid finch found in dry savannah, tropical (lowland) dry grassland and shrubland habitats in northern and eastern Australia.  It is sometimes referred to as Bicheno's finch or as the owl finch, the latter of which owing to the dark ring of feathers around the face.


Nicholas Aylward Vigors and Thomas Horsfield described the double-barred finch in 1827. The specific epithet commemorates James Ebenezer Bicheno, a colonial secretary of Van Diemen's Land appointed in September 1842.
There are two subspecies:
Stizoptera bichenovii bichenovii of eastern Australia
Stizoptera bichenovii annulosa of northern and northwestern Australia, described by John Gould in 1840.


The double-barred finch is a 10–11 cm long munia-like bird. It has a white face bordered with black, brown upperparts and throat, and white underparts. The throat and underparts are separated by another black line. The wings are patterned in brown and white. The sexes are similar, but juveniles are duller and browner.  A less common subspecies with brown or black underparts is known to exist.


The double-barred finch is granivorous and highly gregarious. Nests are built in grass, bushes or low trees, with four to six eggs laid per clutch. The call is a soft tet or a louder peew, and the song is a soft fluting, which is somewhat like the zebra finch.


Tagetes lucida is a perennial plant native to Mexico and Central America.  It is used as a medicinal plant and as a culinary herb.  The leaves have a tarragon-like scent, with hints of anise, and it has entered the nursery trade in North America as a tarragon substitute.  Common names include  sweetscented marigold, Mexican marigold, Mexican mint marigold, Mexican tarragon, sweet mace, Texas tarragon, pericón, yerbaniz, and hierbanís.


Tagetes lucida grows 45–75 cm (18–30 in) tall and requires full sun to light shade. Depending on the variety or landrace, the plant may be fairly upright, while other forms appear bushy with many unbranching stems. The leaves are linear to oblong, about 7.5 cm (3 in) long, and shiny medium green, not blue-green as in French tarragon (Artemisia dracunculus var. sativa). In late summer it bears clusters of small golden yellow flower heads on the ends of the stems.  The flower heads are about 15 mm (1⁄2 in) across and have 3–5 golden-yellow ray florets. The flowers are hermaphroditic (have both male and female organs) and are pollinated by insects.


Tagetes lucida was used by the Aztecs in a ritual incense known as Yauhtli, as well as being dedicated to the rain god Tlāloc. Tagetes lucida is still in use today primarily as a tea to treat the common cold, intestinal gas and diarrhea.
It has been reported that the Huichol of Mexico use the plant as an entheogen by smoking Tagetes lucida with Nicotiana rustica, and that Tagetes lucida is occasionally smoked alone as an hallucinogen. Archaeologists found that the Maya used Tagetes lucida as an additive in tobacco mixtures.
Tagetes lucida also had many culinary uses by the Aztecs including as one of the ingredients added to make the drink chocolatl, which gave it a spicy flavor. Fresh or dried leaves are also used as a tarragon substitute for flavoring soups and sauces. A pleasant anise-flavored tea is brewed using the dried leaves and flower heads. This is primarily used medicinally in Mexico and Central America.
A yellow dye can also be obtained from the flowers, and when the plant is dried and burnt, it is used as an incense and to repel insects.
In one study, methanolic extract from the flower inhibited growth of Staphylococcus aureus, E. coli, and Candida albicans cultures. This effect was enhanced with exposure to ultraviolet light.  The roots, stems, and leaves also had the same effect when irradiated with ultraviolet light.


The plant contains the following compounds:
Anethole
Chavicol
Coumarin
Estragole
Isorhamnetin
Methyleugenol
Quercetin


Talicada nyseus, the red Pierrot, is a small but striking butterfly found in the Indian subcontinent and South-East Asia belonging to the lycaenids, or blues family. The red Pierrots, often found perching on its larva host plant, Kalanchoe, are usually noticed due to their striking patterns and colors.


The butterfly has a wingspan of 3 to 3.5 cm. The upperside of its wings are black except for a large orange portion of the lower edge of the hindwing.
On the underside, the forewing is white with black spots more toward the margin. The hindwing is very striking, it is white with black spots toward the base and the margin has a wide band of orange with white spots. There is a lot of variation found in the blacks spots on the hindwings.


Males and females. Upperside: black or brownish black, in fresh specimens in certain lights with a dull purplish flush. Fore wing: uniform, with a very slender thread-like edging of white to the costa. Hindwing: a large conspicuous orange-red patch on the posterior terminal half of the wing between the dorsum and vein 7; this patch does not extend quite to the termen but leaves a narrow edging of the black ground-colour which is produced inwards in short conical projections in interspaces 2 to 5. Cilia of both fore and hind wings chequered with black and white alternately. Underside: silvery white. Forewing: a quadrate spot on the discocellulars, a broad transverse discal band and the terminal third of the wing jet-black; the discal band is irregular, dislocated on vein 3, the posterior portion shifted inwards and joined onto the black area on the posterior terminal third of the wing by projections of black on the dorsum, along veins 3 and between veins 4 and 5; the black area on terminal third of the wing encloses a transverse postdiscal series of small round and a subterminal transversely near series of spots of the white ground-colour. Hind wing: two spots near base, a subbasal transverse series of three spots, a medial similar series of four somewhat elongate spots and a transverse short postdiscal bar between veins 4 and 6, jet-black; terminal third of the wing above vein 7 jet-black, below that vein deep orange-red, the whole area (both the black and the red) medially traversed by a transverse curved series of round spots of the white ground-colour and margined outwardly by a series of transverse, very short and very slender lines of the same in the interspaces; anteciliary line black. Cilia of both fore and hind wings chequered as on the upperside; a short filamentous tail at apex of vein 2 black, tipped white. Antennae, head, thorax and abdomen black, shafts of the antennae ringed with white; beneath: palpi, thorax and abdomen while.
— Bingham, C.T., 1907


Himalayan foothills, North India, South India, Meghalaya, Assam, Sri Lanka and North Myanmar.


They are widely distributed in peninsular India, and have been recorded from many localities in Maharashtra, Karnataka, Punjab, and Odisha. They are also found in the hilly regions of northeastern India and northern Myanmar. Studies suggest that they may be on the way to colonizing the foothills of the Himalayas due to changes in the habitat.


They are found in semi-arid plains, degraded patches of evergreen patches, and semi-evergreen forest, gardens, hill stations and forests—in fact, wherever its food plant, Kalanchoe, is abundant. It is found from the plains up to 8,000 feet.


The red Pierrot is a weak flier, and flutters about close to the ground. It flies in short bursts and settles often but not for very long. It basks with its wings half open, but prefers shade to sun, and jungle or undergrowth to open areas. It keeps on the wing almost till dark when it settles on the undersides of leaves and twigs often in company. It is sluggish early in the morning and late in the evening.
It visits flowers of herbs, especially of the families Amaranthaceae and Acanthaceae, for nectar. It visits both ornamental and wild flowers and varieties of Alternanthera are among its favourites.
It always sits with its wings closed to display the bright markings of its undersides. It fearlessness, weak flight and distinctive markings all indicate that it is a protected butterfly, which is peculiar considering that its host plants are not known to contain any sequestrable toxins.
There is a mention in literature of the species being found at lights at night, however such phenomena are usually restricted to species that are crepuscular and this occurrence may be incidental.


It is not a common butterfly, but near its food plant, Kalanchoe, it is found in abundance and is gregarious in all its stages.


The female lays eggs on the underside of a leaf. They are light green ellipsoid-shaped small egg. Young and old leaves are selected without discrimination as the leaves of Kalanchoe are thick and succulent during all stages.


The caterpillar is pale yellow to a dirty white, and flattened with large, jet black spiracles. The entire body is covered with tiny white setae or bristle-like hair.
This caterpillar is a leaf miner by habit and this serves as its defense. As soon as it hatches it bores into the leaf and will spend the rest of its life between the epidermal layers of the leaf. Occasionally it will change leaves.
The caterpillar tunnels through the entire leaf in a neat winding manner so as to make sure to consume the entire leaf. It leaves a black trail within that is filled with droppings. The caterpillar can only be seen when it is changing leaves or when it comes to the surface to pupate.
Onisciform, but much rounded, and with the segments at the divisions very clearly defined; head small, almost concealed; last segment flattened. It is in colour fleshy-white, with a row of nine small black dots along the back on each side and a ring of four similar dots on the segment nearest the head; it is profusely covered with small white hairs. It feeds in the interior of the fleshy leaves of Bryophyllum calycinum, only emerging in order to turn into a pupa.
— Davidson, Bell and Aitken quoted in Bingham


At the time of pupation the caterpillar comes out of the leaf and weaves a silk pad and a tight body band and then moults to form the pupa. The pupa can be either on the under or upper surface of the leaf. It is yellow and covered with long light hairs. The pupa is also marked with numerous black spots all over the body.
... much resembles the larva, being short and stout and blunt and covered with short-white hair. It is of the same fleshy colour as the larva and has two lines of small black dots along the surface of the abdomen continued along the thorax. It also has a third row of four similar dots on the middle of the abdomen between them; the two dots on the thorax nearest the head are also connected by two other dots.
— Davidson, Bell and Aitken quoted in Bingham


The larval host plants are Kalanchoe laciniata and K. pinnata of the family Crassulaceae (stonecrop family); the latter host being a common garden plant. Adult butterflies have sometimes been seen to visit lichens. Studies suggest that they collect phenolic substances by scraping lichens.


Tanacetum parthenium, known as feverfew, is a flowering plant in the daisy family, Asteraceae. It may be grown as an ornament, and may be identified by its synonyms, Chrysanthemum parthenium and Pyrethrum parthenium.


The plant is a herbaceous perennial that grows into a small bush, up to 70 cm (28 in) high, with pungently-scented leaves. The leaves are light yellowish green, variously pinnatifid. The conspicuous daisy-like flowers are up to 20 millimetres (3⁄4 in) across, borne in lax corymbs. The outer, ray florets have white ligules and the inner, disc florets are yellow and tubular. It spreads rapidly by seed, and will cover a wide area after a few years.


Feverfew is native to Eurasia, specifically the Balkan Peninsula, Anatolia, and the Caucasus, but cultivation has spread it around the world and the rest of Europe, North America, and Chile.
A perennial herb, it should be planted in full sun, 38 to 46 cm (15–18 in) apart, and cut back to the ground in the autumn. It grows up to 70 cm (28 in) tall. It is hardy to USDA zone 5 (−30 °C (−22 °F)). Outside of its native range, it may become an invasive weed.


In traditional medicine, feverfew has been used to treat headache, but there is no confirmed scientific evidence that it has such an effect. Feverfew contains parthenolide, which is under basic research to assess its properties on cancer. Feverfew is registered as a traditional herbal medicine in the Nordic countries under the brand name Glitinum. Only powdered feverfew is approved in the European Union herbal monograph.


The parthenolide content of commercially available feverfew supplements varies substantially (by more than 40-fold) despite labeling claims of "standardization".


Long-term use of feverfew followed by abrupt discontinuation may induce a withdrawal syndrome featuring rebound headaches and muscle and joint pains. Feverfew may cause allergic reactions, including contact dermatitis. Other side effects have included gastrointestinal upset such as nausea, vomiting, abdominal pain, diarrhea, and flatulence. When the herb is chewed or taken orally it may cause mouth ulcers and swelling and numbness of the mouth. Feverfew should not be taken by pregnant women. It may interact with blood thinners and increase the risk of bleeding, and also may interact with a variety of medications metabolized by the liver.


The word "feverfew" derives from the Latin word febrifugia, meaning "fever reducer," although it no longer is considered useful for that purpose.
Although its earliest medicinal use is unknown, it was documented in the first century (CE) as an anti-inflammatory by the Greek herbalist physician, Dioscorides.


The golden tanager (Tangara arthus) is a species of bird in the family Thraupidae. It is widespread and often common in highland forests of the Andes (from Bolivia and northwards) and Venezuelan Coastal Range in north-western South America.
Its plumage is overall golden-yellow with black to the back, wings, tail and ear-coverts. Some subspecies are partially/largely brown below.


The golden tanager was first described as Tangara Arthus by René Lesson in 1840 on the basis of a specimen from Caracas, Venezuela. The generic name Tangara comes from the Tupí word tangara, meaning dancer. The specific name arthus is in honor of Arthus Bertrand, a French bookseller. Golden tanager is the official common name designated by the International Ornithologists' Union (IOC). Other names for the species include "chestnut-breasted tanager".
The golden tanager is one of 27 species in the genus Tangara. Within the genus, it is part of a species group with the blue-whiskered tanager, green-and-gold tanager, emerald tanager, silver-throated tanager, saffron-crowned tanager, golden-eared tanager, and flame-faced tanager. In the group, it is sister to a clade formed by the emerald and silver-throated tanagers. This placement is supported by mitochondrial DNA evidence. The following cladogram shows phylogenetic relationships within the species group based on the above study:


There are nine recognized subspecies of the golden tanager. The subspecies are differentiated by differences in their appearance and their distribution. All the subspecies excluding arthus are sometimes separated into a distinct species, Tangara aurulenta, on the basis of differences in plumage.
T. a. arthus (Lesson, 1832): The nominate subspecies. It is found in the mountains of northern and western Venezuela.
T. a. palmitae (Meyer de Schauensee, 1947): It is found on the western slope of the Andes in La Palmita, Santander, Colombia.
T. a. sclateri (Lafresnaye, 1854): It is found in the Andes of eastern Colombia, and likely also in those of southern Táchira, Venezuela.
T. a. aurulenta (Lafresnaye, 1843): It is found in Serranía del Perijá, Venezuela, and the western slope of the Andes in eastern Colombia.
T. a. occidentalis Chapman, 1914: It is found on the western slope of the Andes in central Colombia and on both slopes in western Colombia.
T. a. goodsoni Hartert, 1913: It is found on the western slope of the Andes in Ecuador, and likely also in northwestern Peru.
T. a. aequatorialis (Taczanowski & Berlepsch, 1885): It is found on the eastern slope of the Andes in Ecuador and adjoining areas in northern Peru.
T. a. pulchra (Tschudi, 1844): It is found on the eastern slope of the Andes from Amazonas to Junín in Peru.
T. a. sophiae (Berlepsch, 1901): It is found on the eastern slope of the Andes from southeastern Peru to La Paz and Cochabamba in Bolivia.


The golden tanager is found in the Venezuelan Coastal Range in Venezuela and in the Andes in Colombia, Ecuador, Peru, and Bolivia at elevations of 700–2,500 m (2,300–8,200 ft), but is most common at elevations of 1,000–1,500 m (3,300–4,900 ft). It inhabits humid montane evergreen forest, as well as forest edges and nearby secondary growth.


The nominate subspecies of the golden tanager is listed as being a species of least concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List because of its large range, relative commonness, and lack of a sufficiently rapid decline in population. The other subspecies, which are considered to be a distinct species by the IUCN, are also listed as being of least concern for the above reasons. However, the population of the golden tanager is decreasing, and it is threatened by habitat destruction.


Taraxacum erythrospermum, known by the common name red-seeded dandelion, is a species of dandelion introduced to much of North America, but most commonly in the north. It is often considered as a variety of Taraxacum laevigatum (i.e., Taraxacum laevigatum var. erythrospermum). In many characteristics, it is similar to the common dandelion, Taraxacum officinale.