The long-eared owls derives almost of its food energy from rodents. Among this order, they are usually associated with a single group, the voles. The life history of the long-eared owl is inexorably linked to voles. Voles, members of the family Cricetidae and subfamily Arvicolinae, are often numerous, small-to-medium-sized rodents with relatively short tails. In Europe, especially, the long-eared owl can be considered a specialized vole hunter. Out of 86 prey studies in the continent, in about 69% voles made up more than half of the prey. In particular, in the region of central Europe, a little over 82% of 57,500 prey items was made up of voles. Where a variety of voles are available in Europe, long-eared owls show a preference for the most gregariously inclined common vole (Microtus arvalis) over the less sociable field vole (Microtus agrestis). In central Europe, 76% of the diet was compromised by the common vole species alone. More specifically, in the largest known study from Germany, of 45,439 prey items in the regions of Berlin and Nordharz, common vole accounted for 72%, with the field vole and tundra vole (Microtus oeconomus) collectively another 5.5%. Another large representation of the common vole was in Slovakia, where they made up 84.1% of the diet (27,720 out of 32,192 total prey items). In different years in Slovakia, common voles may range from as much as 92.4% to as little as 57.2% depending on vole numbers. Locally, such as in former Czechoslovakia and in western Ukraine, about 94-95% of the diet may be common voles alone (of 4,153 and 5,896 prey items, respectively). The dietary association with the common vole generally continues to most areas of European Russia, such as Moscow. At times, such as indicated in Moldova, long-eared owls are capable of culling as much as 50% of the common vole population and it was opined that the voles would easily become pestilent to humans if not naturally controlled. Like many voles, common voles are subject to population cycles. In accordance with the cyclic nature of vole populations, the local numbers of long-eared owls can rise and fall sharply. In low vole years, they tend to lay fewer eggs and feed fewer young, and may not attempt to breed at all. In high vole years, they generally lay and hatch more eggs and rear more young. While incubation starts with first egg, only the oldest siblings may be feed in low food years. Generally various species of mice are eaten in poor years for common voles but appear to be an inefficient substitute (at least in more northerly climes) based on the owls’ lower breeding rates. Apparently, common voles at times may collectively shift in temporal activity into more diurnal activity in what may be an attempt to mitigate heavy owl predation (especially as basically all European owls tend to hunt them), although several diurnal predators are nearly as specialized predators of them as well. Evidence has indicated that common voles are altering their life cycles with unknown long-term results due likely to global warming. It is likely that the long-eared owls of the region are to be effected by this but it is uncertain exactly what the resulting effect will be.
In some parts of Europe, common voles are at times not found or are locally infrequent or rare, especially on large islands, Scandinavia and some parts of the southern reaches, such as the Iberian Peninsula, Italy and Greece. Therefore, long-eared owls live mostly on different prey species. Supplemental or, occasionally, primary prey when voles are less common are murid rodents, especially the commoner genera such as Apodemus or field mice, Mus or house mice and, occasionally, Rattus or typical rats. In Scandinavian studies, common voles were still the main prey in Finland where distributed (and outnumbered field voles in the owl's diet four-to-one) and partially in Denmark (where foods were split between the two commoner vole species and field mice) but are not in Sweden and Norway. In Sweden, where common voles are not found, field voles were the main food, making up 65.2% of 13,917 prey items, followed by Apodemus field mice species, which were a further 25.3%. In Norway, 3,431 prey items were primarily field voles (42.75%), Apodemus species (12.64%),  tundra voles (12.35%) and bank voles (Myodes glareolus) (12.06%). In the British Isles, primary prey switched between field voles (46.6% of 1,228 prey items in the Peak District and 79% in southern Scotland) and Apodemus mice, most especially the wood mouse (Apodemus sylvaticus), (75.6% of 1,772 prey items pooled from different parts of England and 69.5% of 1,373 prey items in Ireland, where native voles are entirely absent). In warmer areas, the long-eared owls may vary in diet depending on local prey composition. In Spain, voles, including common voles, Mediterranean pine voles (Microtus duodecimcostatus) and Lusitanian pine vole (Microtus lusitanicus), collectively made up 76.4% of 6,945 prey items in the central part of the country while on the Ebro in northern Spain, the Algerian mouse (Mus spretus) was dominant, at 69.5% of 846 prey items. Overall, in 7 studies from assorted Spanish locations, wood mice and Mus species were the most regular prey (together accounting for just under 60% of the sum total prey items). Many studies in Italy show that the species is not as much of a specialized feeder in the country with considerable regional variation in prey preferences. Inclement weather in particular, including any kind of precipitation or high winds, seems to cause Italian long-eared owls to increase the diversity of prey that's routinely caught. In some Italian studies, Savi's pine vole (Microtus savii) were the main food, at Prignano Cilento where they made up 60.4% by number and 61.6% by biomass. In others, the wood mouse was the main food, such as Cremona, at 59.1% of 1,482 prey items. An unusual close prey association was noted in northern Italy, where access to landfills allowed them access to exceptionally large prey, brown rat (Rattus norvegicus), with juvenile rats caught that weighed on average 140 g (4.9 oz) and sometimes weighing up to 243 g (8.6 oz), making up 20.5% by number and 65.1% by biomass, although wood mice were the most numerous found prey in pellets. Because of the access to rats, the mean prey size in the north Italian study was an exceptionally high 58 g (2.0 oz) Generally, Mus mice seem to be the main foods for long-eared owls in Greece, especially the Macedonian mouse (Mus macedonicus), but also not infrequently the southern vole (Microtus levis) is important in the diet there as well. In the Canary Islands, the introduced house mouse (Mus musculus) was deemed to primarily support the owls today, consisting of 69.5% of 3,628 prey items per the largest known study.
Outside of Europe within Eurasia, the feeding association with voles for long-eared owls weakens somewhat but does continue apiece in adjacent Turkey, particularly southern vole and Günther's vole (Microtus guentheri) (the latter, for instance, making up to 78.7% of 5,324 prey items in Karapınar). In the Middle East, prey preferences varied based on soil composition in desert edge areas, with Israeli studies showing primary shifting rapidly from Gerbillus gerbil species to Meriones jirds to Günther's voles, with similar findings in wintering owls in Iran. Relatively large-sized prey, Indian gerbils (Tatera indica) and short-tailed bandicoot rats (Nesokia indica),  was reported for wintering long-eared owls in Iran estimated to average 163 g (5.7 oz) and 155 g (5.5 oz), respectively, constituted a good portion of the prey (72.9% of biomass) and taken in almost even numbers with smaller Gerbillus species. Much further east, in China and Mongolia, long-eared owls often subsist on different varieties rodent, especially small hamsters, which are also cricetid but not arvicoline, such as the Chinese striped (Cricetulus barabensis) and Roborovski dwarves (Phodopus roborovskii), alternatively with larger jirds, such as midday jirds (Meriones meridianus), as well as house mice. In more northerly eastern regions, voles continue to be of import. In western Siberia, tundra voles, narrow-headed voles (Microtus gregalis), Eurasian harvest mouse (Micromys minutus) and steppe lemming (Lagurus lagurus) were the main rodent prey. In Japan, diet is strongly biased to rodents such as Japanese grass vole (Microtus montebelli) (84.2% of foods in Niigata on Honshu), grey red-backed vole (Myodes rufocanus) (87.2% on Hokkaido) or house mouse (77.7% in Ehime Prefecture, Shikoku).
In North America, long-eared owls also primarily rely on small rodents in their diet, but their diet is somewhat more diverse by rodent family and less completely reliant on voles than their Eurasian counterparts. In general, the further north they are found in North America, the more restricted and vole based the diet is for this species. While diets are poorly researched in detail in Canada, in the northern tier states of Massachusetts, Michigan, Minnesota, Ohio, New York, Wisconsin and northern Oregon voles were easily the main prey for long-eared owls. In particular, the meadow vole (Microtus pennsylvanicus) tends to be a dietary staple, such as in the two of the larger American studies, in Michigan where they constituted 70.6% of 3,269 prey items and in Wisconsin where they constituted 83.4% of 3,273 prey items. Another regularly featured vole in the diet in America is the prairie vole (Microtus ochrogaster), but few other voles seem to be taken other than opportunistically excluding Oregon where the gray-tailed vole (Microtus canicaudus) and Townsend's vole (Microtus townsendii) locally led the foods. In North America, non-arvicoline cricetid rodents such as the genus Peromyscus, or deermice, and the smaller Reithrodontomys, or harvest mice, fill the niche of small wild mice and may be irresistible to hunting long-eared owls. Peromyscus mice were the main foods for this species in Colorado, Illinois and most studies from Iowa (composing up to 59.1% of the local diet).
In many areas, particular arid vicinities, the superfamily Geomyoidea supplants cricetid rodents as the primary foods, namely pocket mice, kangaroo rats and occasionally pocket gophers and jumping mice. Particularly this appears to be the case in the American southwest where in Arizona, Perognathus pocket mice composed 61.3% of the diet, in New Mexico, where species pairs of pocket mice and kangaroo rats composed 51.8% and 20.5% of the foods, respectively, and in southern California, where Perognathus were 51% of foods and Dipodomys kangaroo rats were a further 37.8% of the foods. In the Sonoran desert of Mexico, nearly all known prey were geomyoids, in particular the Merriam's kangaroo rat (Dipodomys merriami), which alone made up 74.7% of the foods. In a well-studied population, Snake River region of southeastern Idaho as well as Owyhee county in the southwest part of the state, geomyoid rodents are usually the most prominent prey, especially the Great Basin pocket mouse (Perognathus parvus) and Ord's kangaroo rat (Dipodomys ordii) (often supplemented heavily with Peromyscus mice). Due to the relatively large size of kangaroo rats, in Idaho, mean prey size may range up to at least 41 g (1.4 oz) In some parts of North America, richer biomass are likely when larger prey takes the primary position, such as cotton rats. Cotton rats were the main prey in Janos Biosphere Reserve, Mexico (43.2% by number, 69.1% by biomass) and in Texas, in the latter slightly outnumbering (36%) the much smaller harvest mice (23%). Since the mean body size of hispid cotton rats (Sigmodon hispidus) caught reportedly is around 100 g (3.5 oz), they probably represent a very productive prey resource for long-eared owls. Similarly, exceptional large prey was taken northeastern Oregon, where both juvenile, weighing about 30 g (1.1 oz) and adult, weighing about 90 g (3.2 oz), northern pocket gophers (Thomomys talpoides) were caught and made up 55.7% by number and 74.4% by biomass of the diets of long-eared owls. Depending on circumstances, the mean size of northern pocket gophers taken in different areas can vary from 41 to 100 g (1.4 to 3.5 oz) or higher, but long-eared owls usually take juveniles outside of the Oregon study (weighing on the lower end of that mass scale).
Non-rodent mammalian prey is seldom of great import to long-eared owls, though they can take some numbers of other kinds of mammals locally. Despite claims that the long-eared owls “avoids” shrews as prey, it is probably more correct to say that they do not seek them out nearly as often as more socially inclined and/or densely populated rodent prey. Some other owls may be considered regular and common shrew predators, such as often barn owls. In Europe, a broad picture of prey selection indicates about 2% of the diet of long-eared owls consists of shrews. Locally, relatively high numbers of shrews were reported in Finland, where 10.7% of 3,759 prey items were common shrews (Sorex araneus), in southern Scotland, where the common shrew made up 17.3% of 514 prey items, in northeast Greece, where lesser white-toothed shrew (Crocidura suaveolens)  were 19.3% of 311 prey items and in western Siberia, where Sorex species were 17.3% of 335 prey items. Similarly, in North America, shrews are rarely more than secondary prey. Exceptionally high numbers of shrews were noted in Ohio, where the relatively large northern short-tailed shrew (Blarina brevicauda) and the relatively small North American least shrew (Cryptotis parva) made up 10.46% and 10.22% of the diet, respectively, and in Tennessee, where 12.85% of the diet was least shrew. The smallest mammal on earth (and thus smallest recorded mammalian or vertebrate prey), the 1.8 g (0.063 oz) Etruscan shrew (Suncus etruscus), may be seldom hunted by long-eared owls. Bats are another supplemental prey type for long-eared owls. One compilation study based on 12 study sites in the Mediterranean area (in Spain, Italy, Greece, Slovenia, Romania and Switzerland) found up to 2% of prey remains were bats. The bats taken in the Mediterranean region ranged in size from the whiskered bat (Myotis mystacinus), estimated at as low as 4 g (0.14 oz), to the European free-tailed bat (Tadarida teniotis), estimated to weigh up to 54 g (1.9 oz). A exceptionally close predatory relationship was noted between bats, especially Japanese house bats (Pipistrellus abramus), and long-eared owls in the Beijing area of China, where bats accounted for 28.6% of 3,561 prey items overall, and 56.6% of the diet locally in urban, rather than suburban, roosts. Other mammals, outside of aforementioned groups (i.e. cricetid, murid and geomyoid) rodents, are known to be hunted but are generally a negligible part of the long-eared owl's diet, including hedgehogs, moles, rabbits and hares and weasels as well as rarely taken rodents like dormice, flying squirrels and squirrels (including chipmunks). While lagomorphs such as hares and rabbits are very rare prey for long-eared owls, occasionally they may capture one. Such prey was estimated to weigh 271 g (9.6 oz) (for cottontail rabbits) and 471 g (1.038 lb) (for jackrabbits) in Idaho, meaning very small young rabbits and jackrabbits are likely captured. However, sometimes long-eared owls can very rarely capture exceptionally large lagomorphs. The record sized mammalian prey to be taken by a long-eared owl, was recorded in the case of predation upon a probable juvenile black-tailed jackrabbit (Lepus californicus) which weighed an estimated 800 g (1.8 lb). Two instances of scavenging on carrion were reported in Italy, the first known case of this for the species, where long-eared owls consumed parts of an adult crested porcupine (Hystrix cristata) and an adult European pine marten (Martes martes), both prey the long-eared owls were certainly unlikely to have killed.


Long-eared owls are generally infrequent predators of birds. Food studies from Eurasia place it as an opportunistic and occasional bird predator, while in North America they are do not seem to generally take large numbers of birds in any area. In winter, sometimes these owls can come to live largely off of small birds gathered in communal sleeping places, often near villages or towns. Particularly snow cover during winter is likely to influence local long-eared owls to switch from mammalian to avian prey. Like barn owls, long-eared owls have been known to hover around roosts in bushes in attempts to disturb the sleeping birds, which may provoke the prey to fly out of their shelter, only to be caught. Long-eared owls, along with migrating short-eared owls, were observed in Spain hunting night-migrating passerines that were attracted to manmade light sources. When killing birds, long-eared owls are very likely to peck about the rear part of the body and the head and decapitate their victims, resulting in more skeletal damage than is typical in other owls and making prey identification potentially difficult. Particularly often taken by long-eared owls in urban areas and/or the edge of arid habitat are house sparrows (Passer domesticus) and occasionally the Eurasian tree sparrow (Passer montanus). A surprisingly high balance of prey for wintering long-eared owls in desert areas was shown to be avian. This was in the case in Algeria, where 37.5% of the diet and 40% of the biomass were avian and the most identified overall prey genus was Passer species, at 20.7% by number and 17% of biomass. For wintering owls in the city of Jerusalem, 90.7% of the diet (150 prey items) were small birds, led by house sparrow (22%) and the blackcap (Sylvia atricapilla) (16.7%). Further study of the long-eared owl's diet in Israel's Negev desert showed that 28.3% of 3,062 prey items were birds. In Egypt, 24.6% of prey items were birds including house sparrow (15.4%) and European goldfinch (Carduelis carduelis) (2.4%). In Europe, birds rarely compromise a majority of the foods, but hearty numbers are taken in several areas nonetheless. In central Europe, birds were estimated to contribute an average of 8% of the diet (of 52 species). In peak vole years, birds could be less than 2% of the foods while in vole low years, as much as 33% were made up of by birds. Similarly, in the Sofia park, Bulgaria, the number of birds, with an average 9.6% by number and 7.9% by biomass,  was variable based on vole numbers but a high number of 44 avian prey species were recorded. In the Sonian Forest, Belgium, 38.3% of 355 prey items were birds, mostly of various passerine species. A study in Baden-Württemberg, Germany found birds to compromise 14.75% of 12,890 prey items, a relatively high balance, with the most common identified bird species being the European goldfinch. Overall British studies found in a sample of 7,161 prey items that 1,161 were birds (14.95%) and that bird were present in 90% of examined pellets. Of these, 46.9% were house sparrow, 7.5% were common starling (Sturnus vulgaris), 4.65% were common blackbird (Turdus merula), 3.35% were European greenfinch (Chloris chloris), 2.92% were song thrush (Turdus philomelos), 2.49% were Eurasian skylark (Alauda arvensis) and 2.23% were common linnet (Linaria cannabina). More locally in the Peak District of England, birds were 23% of the prey by number and 31.3% by biomass. Of the birds examined here, a majority of those identified were meadow pipits (Anthus pratensis) followed by twite (Linaria flavirostris), and identified birds ranged in size from a probable wood warbler (Phylloscopus sibilatrix) (average adult weight 9.2 g (0.32 oz)) to an adult northern lapwing (Vanellus vanellus) (average adult weight 219 g (7.7 oz)). Furthermore, 80% by number and 11 of 25 bird prey species were characteristic of open habitat.
Many Italian studies reflect relatively high numbers of birds being hunted, mainly in the non-breeding times. One of the smaller large representations was at Prignano Cilento where 13.85% were made up of mostly unidentified birds. In Regional Park of Decima-Malafede, birds were 31.1% of the diet, 13.7% of which were unidentified passerines, while European goldfinches and European greenfinch accounted for a further 7.1% and 4.6% of the prey items. In the Venice area, of 642 prey items examined and a total prey mass of 15,038 g (33.153 lb), birds made up 38.47% by number and 41% of the biomass. In the winter roost of Imperia, 63.43% of 1,020 prey items were birds and 36.57% were mammals. The main prey identified was the blackcap (51.6%) while the chaffinch (Fringilla coelebs) was secondary among avian prey (6.73%). In Romanian studies avian prey was relatively important as well.  In Agigea there, 32.71% of the foods were birds, with Carduelis species combined constituting 6.04% and swallows being secondary such as the common house martin (Delichon urbicum) (2.52%) and the barn swallow (Hirundo rustica) (2.44%). Birds were the main foods for wintering long-eared owls in Romania's Danube delta, with birds making up 59.5% of total prey by number and 51.6% by biomass of 948 prey items against 40.7% by number and 48.4% by biomass for mammals. Here, numerous passerines were mostly taken with the finch family (18.6%), Old World sparrow family (15.7%) and the tit family (12.7%) being the commonest prey families among the birds. The mean bird prey size was calculated at 22.2 g (0.78 oz) while the mean mammal prey size was 24 g (0.85 oz). House sparrows accounted for 14.3% of biomass and Eurasian blackbirds for 12.3% of the biomass on the Danube. While mammals usually are dominant in the diets of long-eared owls in Spain, in the Albufera reserve of the nation, birds were 53.5% by number and 48.6% of the biomass of 864 prey items. A total of 34 species of birds were noted, led by common chiffchaff (Phylloscopus collybita) (12.5% by number, 4.8% by biomass), house sparrow (8.2% by number, 12.2% by biomass), barn swallow (6.4% by number, 7% by biomass) and sand martin (Riparia riparia) (3.2% by number, 2.7% by biomass). The main recorded individual prey species in Beijing was the Eurasian tree sparrow, at 38% of the diet, but other avian prey was negligible here.
While most of the passerines attacked by long-eared owls are well within typical prey sizes for this species, while pursuing bird prey many reports note that unusually large prey may be attacked. Avian prey weighing around 100 g (3.5 oz) or somewhat higher such as the larger common thrushes or jays is not uncommonly taken. However, unusually large bird prey for long-eared owls in Europe has included several species at least twice as massive, including adults of the following species: northern lapwings, common wood pigeon (Columbus palumbus), with an average adult weight of 490 g (1.08 lb), common moorhens (Gallinula chloropus), with an average adult weight of 343 g (12.1 oz), red-legged partridges (Alectoris rufa), with an average adult weight of 528 g (1.164 lb), western jackdaws (Corvus monedula), with an average adult weight of 246 g (8.7 oz) and Eurasian magpies (Pica pica), with an average adult weight of 230 g (8.1 oz). Much of the largest identifiable and provable prey for long-eared owls in Europe overall were found to be birds. Despite the relatively scarcity of avian prey in the diet in North America, unusually large avian prey has been reported there as well. Such prey have included adults of Northwestern crow (Corvus caurinus), averaging 392 g (13.8 oz), two large adult ruffed grouse (Bonasa umbellus), estimated to weigh slightly over 600 g (1.3 lb), and even apparently at least once an adult sharp-tailed grouse (Tympanuchus phasianellus), which average a relatively huge 885 g (1.951 lb) or three times heavier than an average long-eared owl.


Other than mammals, which compromise a great majority of foods, and birds, which compromise a secondary but locally important portion of the foods, other prey varieties are seldom taken by long-eared owls anywhere. Infrequently, reptiles such as handful of species of snakes and lizards and even fewer amphibians such as frogs and toads. Generally these prey turn up more than singly only as far as is known in slightly arid warmer parts of the species range, mostly within the Canary islands and occasionally the American southwest. Fish are almost never recorded in the diet with a total of two prey fish species, both carp and further unidentified carp, recorded in Europe. Despite a rather high diversities of insects (and a low diversity of other invertebrates like arachnids) collected overall, especially in different parts of Eurasia, they are rarely significant contributors to the long-eared owl's diet. Usually in Europe, if any insects are found in pellets, they tend to contribute less than 2% to the prey numbers. Similarly present but slight numbers of insects were noted in Israel as well. Exceptionally large contributor of insects, most often a variety of species or genera of beetle, to prey numbers are noted in some studies such as contributing 6.6% of the diet in Regional Park of Decima-Malafede in Italy, 17.5% in northeastern Greece and 13.3% in western Spain. The record contribution for insects surely for Europe was study in central Poland where a single beetle, the common cockchafer (Melolontha melolontha), was found to constitute 25% of the prey items. Based on a couple studies in Algeria, insects are a common supplemental food there, contributing up to about 17.3% of the prey items. On the isle of Tenerife in the Canary islands, an exceptional 33% of the food was recorded to be insects, with both bush crickets and field crickets contributing 14.8% each, although in broader Canary island studies the significance of insects is reduced to 10.4%. The maximum known contribution of insects to the diet in North America was merely 4.3% of the foods for communal roosting long-eared owls in southeast Idaho.


The long-eared owl occurs in multiple competitive environments of the temperate zone alongside other birds of prey. A wide variety of owls are especially likely to be encountered both in terms of shared nocturnality and a shared preference for rodent prey, which is favored by about 75% of owls found in North America and about 85% of the owls found in Europe and occasionally favored by nearly all owls in both continents. Much study has gone into contrasting the ecology of long-eared owls against other owls and also occasionally diurnal birds of prey, especially in terms of differences in dietary habits and habitat preferences. In Europe, arguably the most populous owl is likely the tawny owl, which has therefore warranted a considerable number of comparisons with long-eared owls. While tawny owls overlap in prey preferences with the long-eared owl, it tends to show greater dietary flexibility, with larger contributions of secondary prey such as birds, reptiles and amphibians and insects. For example, in southern Sweden, the food niche breadth of tawny owls was roughly three times greater than that of long-eared owls. Generally tawny owls prefer more extensively wooded environments than long-eared owls but can adapt as well as the long-eared to forest fragmentation and peri-urbanisation, thus often competing rather directly over foods. While the tawny owl usually selects slightly larger prey on average than long-eared owls, often over 30 g (1.1 oz) mean prey mass, studied size of common voles hunted in central Lithuania showed that both long-eared and tawny owls selected larger than average voles, with average caught estimated at 21.45 g (0.757 oz) against the average weight surveyed by humans at 16.42 g (0.579 oz). Surprisingly, especially in the non-breeding season in this study, long-eared owls in Lithuania tended to select larger voles on average (at 21.56 g (0.761 oz)) than did tawny owls (19.56 g (0.690 oz)). Despite the potential for competition and mortality (for long-eared owls) in the interspecific relationship between the tawny and long-eared owls, the proximity of tawny owls in a study from Switzerland appeared to have no deleterious effect on the breeding on the long-eared species. A few studies have examined the habits of the little owl, probably the next most common European owl and just ahead of the long-eared owl in third, and the long-eared owl in areas where their somewhat overlapping habitat preferences draw them into similar areas. However, the long-eared owl takes larger prey on average usually than little owls, since it focuses more on rodents rather than invertebrates like insects and earthworms and, especially during winter, varies its prey compositions less so than the smaller species. Also, the long-eared owl requires some timbered spots for roosting purposes while little owls can adapt to both treeless and partially treed areas as well as, in Spain at least, more heavily modified areas by humans. Many diurnal raptors in Europe broadly overlap in dietary habits, largely taking voles where they are available, including most species of harrier, buzzards and some falcons, especially common kestrels (Falco tinnunculus). Other than occasional predatory interactions, competition is limited with most of these diurnal birds of prey due to the temporal differences of their habits. In Europe, several other owls, from ones much smaller than to a few species much larger than a long-eared owl, prefer voles and/or lemmings as prey but often differ considerably in their habitat preferences, distributions, nesting habits and/or hunting habits so the long-eared owls are largely naturally partitioned from competing directly with them.
On a broader scale, both short-eared owls and barn owls potentially compete for resources with long-eared owls. Despite considerable overlap in both range and diet, long-eared owls are largely buffered from considerable competition with short-eared owls by habitat preferences, as the short-eared owls always venture to more open habitats, generally roosting and nesting in tall grasses rather than timber, and seldom, if ever, hunt in the same edge habitats as the long-eared species. In western Russia when compared to short-eared owl, long-eared owl showed less of a tendency to appear in cluster where prey was concentrated, most likely because of the habitat differences. In both western Russia and further east in western Siberia, the short-eared tended to take more tundra voles in addition to common voles, while long-eared owls focused more exclusively on common voles. Comparisons between barn and long-eared owls have been made in many areas of the latter species less extensive range. The habitats used by the barn and long-eared owls are not mutually exclusive nor are their prey species. Despite being similar aerial hunters of open areas, barn owls differ in life history in many respects from long-eared owls, in part by being cavity nesters. While their dietary habits can appear similar and show similar dependence on small mammals, barn owls are somewhat more generalized and catholic as feeders, with less of a heavy reliance on voles. Barn owls can live quite well on virtually any small mammal assemblage. In some parts of Europe, the two species’ food niche breadth is comparable or even slightly higher in the long-eared. However, globally barn owls are much more wide-ranging, more tropical in their central range and globally have a much wider prey spectrum than long-eared owls. Barn owls are also more widely adaptive to insular living than long-eared owls, and are capable living proficiently on a diversity of prey classes even in environments completely lacking small mammals. The American barn owl race is larger than the western barn owl race from Europe and relevant parts of Asia, being more comparable in body mass and foot and talon size to the tawny owl while the western race in Europe is roughly intermediate between the tawny and long-eared owls in body size and foot span. Consequently, in the Americas, barn owls tend to consistently take slightly larger prey than long-eared owls and tend to access a broader overall feeding niche. Despite the great adaptability and range of the barn owl, it was found in a study from France that they experience higher mortality due to starvation than long-eared and tawny owls. This was attributed to the barn owl's inferior lipid fat reserves while they attempt to survive the cooler seasons within temperate climates, as they are better suited to survival in warmer climates.
North America has more species of owl than Europe and can be considered a more competitive environment for long-eared owls living there. However, again, in most cases habitat preferences, slight partitioning in dietary preferences (which may be in prey species or body sizes of prey selected) and life histories generally allow most species to persist even when living in proximity to one another. As throughout their range, long-eared owls tend to differ from most other North American owls by being much more migratory in nature. Therefore, cyclic food variations affect them differently and are less likely to be the direct cause of winter mortality than in more permanently residential owls. Oddly enough, among American owls, long-eared owls most strongly mirror the much smaller northern saw-whet owl in distribution, migratory habits and, to a lesser extent, food habits. The main food of saw-whet owls tends to be Peromyscus mice where they are available and, like most owls, their rodent food selection can broadly overlap with that of long-eared owls. It has been posited that the less broadly ranging occurrence of long-eared owls in general compared to in their European range is in part due to greater resource competition between them and the two widespread screech owls, the eastern (Megascops asio) and western screech owls (Megascops kennicotti). However, the feeding niche tends to be much wider and more opportunistic in screech owls, which often feed on a diversity of invertebrates (mainly insects but also crayfish) and alternate prey (a higher balance of birds and frogs, for instance) and so are unlikely to competitively limit rodent numbers to the detriment of long-eared owls.
The most easily observed and most dramatic portion of interspecies owl and raptor ecology is interspecific predations. In this regard, long-eared owls are much more often the victims rather than the predators. Their generally successful life history on the contrary often makes long-eared owls perhaps more vulnerable than most other medium-sized owls to predations and even perhaps many smaller owl species. These include nesting in relatively open abandoned bird nests rather than hard to access cavities. Also, long-eared owls tendency to occur in quite open areas whilst hunting coupled with the loud vocalizations (including begging calls of their fledglings) and other auditory displays are all likely to court predators. In Europe, their most serious predators tend to be the Eurasian eagle-owl and the northern goshawk (Accipiter gentilis). One account recorded 768 instances of predation by eagle-owls and 317 by goshawks (or 55% of the owl prey for recorded for goshawks in Europe). Long-eared owls rank in the five most regular predated bird species by eagle-owls in Europe. Some biologists feel that long-eared owls tendency to avoid richer prey concentrations in favor of opener habitats and spatial usage, especially while migrating and wintering, is partial dictated by the detection of eagle-owl (and perhaps goshawk) activity, so therefore the eagle-owl has a serious influence on the long-eared owl's life history. In general, long-eared owls endure predation by a formidable array of diurnal birds of prey in Europe. It is likely that largely perch hunting raptor such as Buteo and most eagles may either chance upon an owl roost during a hunting foray or encounter a long-eared owl perhaps during overlapping activity around dawn or dusk, while large falcons are likely to only strike one down when an owl is flushed during daytime. Goshawks and other Accipiter hawks are a particularly deadly threat among diurnal raptors due to their intensive searching hunting methods and willingness to dive into wooded thickets holding roosting owls. Beyond goshawks, diurnal raptors in Europe known to be predators of long-eared owls of potentially any age are known to include golden eagle (Aquila chrysaetos), Bonelli's eagle (Aquila fasciata), eastern imperial eagle (Aquila heliaca), greater spotted eagle (Clanga clanga), lesser spotted eagle (Clanga pomarina), black kite (Milvus migrans), red kite (Milvus milvus), white-tailed eagle (Haliaeetus albicilla), common buzzard, rough-legged buzzard (Buteo lagopus), peregrine falcon (Falco peregrinus), saker falcon (Falco cherrug) and even (in two cases) the slightly smaller Eurasian sparrowhawk (Accipiter nisus). Other than eagle-owls, tawny owls and Ural owls (Strix uralensis) regularly kill long-eared owls where their ranges meet, though in some cases these may begin as territorial attacks by the Strix owls, the smaller long-eared may be consumed regardless.
In North America, the range of predators of long-eared owls is no less daunting. Undoubtedly the most dangerous American predator is the great horned owl. Similarly as in its European eagle-owl counterpart, horned owls kill long-eared owls regardless of season and conditions. However, despite many accounts of predation, long-eared owls do not generally seem to be as prominent in the diet of great horned owls, at least as so far documented, as they are in the diet of Eurasian eagle-owls. Barred owls can also be somewhat serious predators of long-eared owls as well. Rarer acts of predation on long-eared owls in North America have reportedly been committed by spotted owls (Strix occidentalis) and even their cousins, the short-eared owl. Diurnal predators of long-eared owls including some species that also hunt them in Europe such as golden eagles, northern goshawks and peregrine falcons, as well as bald eagle (Haliaeetus leucocephalus), Cooper's hawk (Accipiter cooperii), red-tailed hawk (Buteo jamaicensis) and red-shouldered hawk (Buteo lineatus). Though less well documented throughout the range, long-eared owls are also vulnerable to mammalian predators, mainly near the nest. Suspected or confirmed predators in Europe are often European pine martens or stone martens (Martes foina), which are likely to depredate nestlings but also will consume eggs and adults if they are able to ambush them. Martens are also a potential threat in North America, as are the North American porcupine (Erethizon dorsatum), bullsnake (Pituophis catenifer) and, especially, the raccoon (Procyon lotor) (the latter species may semi-regularly kill and eat brooding adult female long-eared owls). Corvids, many of which build the nests long-eared owls use, such as magpies and crows will also semi-regularly raid the long-eared owl's nests and eat the eggs or nestlings. On the other side of the equation, long-eared owls themselves may infrequently prey on smaller owls. This species has been known to hunt eastern screech owls, little owls, Eurasian pygmy owls (Glaucidium passerinum) and boreal owls (Aegolius funereus), as well as the young of the common kestrel.


Long-eared owls tend to be monogamous breeders. Non-migratory populations are usually monogamous throughout the year, the pair bond being renewed annually. A study in Idaho determined that long-eared owls were locally extremely monogamous, with no extra-pair fertilizations were detected in 59 nestlings from 12 nests. There is a single record of a male breeding with 2 females in Netherlands, a very atypical case. Similarly, evidence of polyandry and alloparenting was found in a nest in western Montana where the four offspring of the female owl had two fathers, one of which was related to the female. Males claim their territory with singing and display flights with wing clapping. Singing normally starts at dusk on calm evenings and may continue through the night, clear windless moonlit nights are preferred. The song is usually delivered from a perch, most often at medium height in trees or from the upper half near the canopy, sometimes in flight. Males are responsive to playback during the period leading up to the breeding season (especially during courtship), to such a degree 45% territories would've been undetected in Spain if males has not responded to recordings (as opposed to listening for spontaneous callings). Often between 8 and 50 pairs are recorded in different parts of the range in a typical range of 100 km² (39 sq mi). In Scotland, about 17% of the 9-18 pairs per 10 km² (3.9 sq mi) were non-breeders. Typical territories for pairs are 50 to 100 ha (0.19 to 0.39 sq mi) in Finland when voles are plentiful. Several pairs may nest rather close together nonetheless. The minimal distance is normally around 50 to 150 m (160 to 490 ft) between active nests, but in Idaho a nearest nest distance of only 16 m (52 ft) was recorded. When food is abundant, about 10-12 pairs, infrequently as many as 50, may nest within area of 100 km² (39 sq mi). Pairs may tolerate each other in the same patch of trees while nesting if food supplies are abundant. A study in Province of Pisa of Italy of 32 territories found 10-15 pairs per 100 km² (39 sq mi) with a mean nest spacing of 1,727 m (5,666 ft). In a south-central Idaho study area, pair occurred on average 0.65 km (0.40 mi) apart. The highest densities may come from central Europe. The average density in central Europe is typically around 10-12 pairs per 100 km² (39 sq mi). However, in Brandenburg, Germany, over a 24-year study, it was found the average density was 72.7 pairs per 100 km² (39 sq mi). Based on studies from Michigan and Wyoming, anywhere from 10 to 100 pairs per 100 km² (39 sq mi) was estimated, with the average range in Wyoming riparian habitat about 55 ha (0.21 sq mi). Densities appeared lower in the Snake River area (0.28-0.42 pairs per square km) than elsewhere in southern Idaho (0.64-1.55 pairs per square km). Globally, many pairs of long-eared owl occupy the same territory all year around but most prefer to use a different nest each year even if the same nest as last year is still in good standing. Females typically take on the duty of inspecting potential nesting sites and duets with its mate; perched on a chosen nest, she sings to contact the male, later vocal activity is confined to weak calls only heard at short range. During displays, females have also have been recorded doing the wing clap display but much less intensely than males. Copulation tends to occur close to the nest. In Germany, it was recorded that the male precedes copulation with calls and display flights, followed by strong waving wing signals and tilting their body while perched near female and/or the nest. Copulation has also been observed on both the ground and the trees, preceded frequently by a duet, a male aerial display which ending in descent to ground and a flight by the female. Boundary fights between males are unrecorded in this species. Breeding occurs later in the year than sympatric species such as tawny owls and barn owls perhaps due to their more strongly migratory ways. Rarely mating may occur early as February in cooler temperate areas, but the pairs copulations usually take place in March or April. Winter breeding detected as new juveniles of 14–18 days of age were recorded in early February in Slovakia. Other prior reports of winter breeding are known from Italy, in two cases, as well as in the Czech Republic.
Normally nests in stick nest of large birds, i.e. Corvus, Pica, raptors and Ardea herons. Other nest builders in Europe can often include common wood pigeons and Eurasian sparrowhawks. In Britain and Finland 84% of 239 and 85 nest were made by carrion (Corvus corone) or hooded crows (Corvus cornix) and Eurasian magpies. In England and Finland, 77% and 66% of the nest were in conifers, respectively. In Brandenburg, Germany, 90% of the nest were built by carrion crows and most were in Pinus sylvestris. In different studies of Idaho, nearly all known nests were in old corvid nests (most being in juniper). In one large study, nest heights, which averaged 3.2 m (10 ft), and diameter of the nest construction, which averaged 22.3 cm (8.8 in), were deemed likely to be the most significant criteria for nest selection. In Ontario, conifers were usually used, often Pinus or Juniperus, in corvid nests between 2.5 and 18.5 m (8.2 and 60.7 ft) high, but mostly between 5.5 and 9 m (18 and 30 ft). Nest height averaged 6.7 m (22 ft) in Great Britain. In Slovenia, long-eared owls preferred coniferous trees for breeding (in almost exclusively corvid nests), those that nested in deciduous trees had higher nest mortality especially earlier in the season due to higher predation rates. Similarly, nest site selection was largely correlated to predation risk in Spain, with ivy and tree canopy coverage less important than high scrub cover from below, in part because terrestrial predators were more common in the particular study area than aerial ones. In northeast Switzerland, nesting location are selected for anti-predator features, among 38 nesting sites, the ones seemingly preferred bore denser forest edges, greater canopy cover and were within conifers much more so than were prevalent in the overall environment, while the vicinities of buildings were avoided in the study area. An unusual case of urban breeding long-eared owls was observed in Moscow, Russia, where a loose colony was observed to form. The Moscow nesting was thought to be the result of synanthropization by the owls, in part due to lower predation risk in the urban areas versus rural vicinities (where predation was 6.6% higher). The mean distance of nesting owls in Moscow was 603 m (1,978 ft) whereas it was more than twice the distance in nearby rural areas. Tree nests are usually under 30 m (98 ft) above the ground, and can sometimes be so small that the wings and tail of brooding female may be visible from below. More infrequently than avian tree nests, leaf nests of tree squirrels, hawk nests in cacti and cliff nests of various birds may be used. While they usually take up already abandoned nest sites, sometimes long-eared owls are capable of chasing off prior occupant of nest even including other raptors (extending to fierce Accipiters such as sparrowhawks, sharp-shinned hawks and even larger Cooper's hawks) indicative of their potential for fierceness and tenacity. Other than other bird's nests, alternate nesting sites have been used but appear to be usually rare or uncommon. Among these, are shallow depressions on the ground. Some ground nest locations recorded (in Europe) have included among heather, bracken and bramble, and even on reed beds, rabbit warrens. Some nests have been recorded in wicker baskets placed in trees for ducks. In North America, pairs of ground nest were found in each west-central Montana and in Okavagan, British Columbia, in all cases between the roots of or the ground immediate adjacent to the base of trees or bushes (with two other historic records of ground nesting in North America). Artificial nesting platforms made of twigs for the owls are also locally accepted. In Woodwalton Fen reserve of eastern England, 71 nests were built in wicker baskets set out for owls. Also in Yizre'el in Israel, 6 of 16 nest baskets hung in Eucalyptus were used by long-eared owls, with all occupied by February. In this general area of Israel, at least 72 other nest baskets for long-eared owls have been set out, to encourage the rodent controlling birds.  Exceptionally, long-eared owls have nested in shallow cavities, in hollow willows or oaks, tree stumps or holes in cliffsides, however as a rule they tend to not be cavity nesters. 6.5% of 153 nests in Great Britain were on natural surfaces (mostly the ground) rather than animal nests. Nesting vicinities where previous attempts were successful are more likely to be reused, i.e. in Idaho where 48% of prior nesting areas were reused after successful attempts.
Egg-laying is between normally between late March and early May in most of the range. Egg laying dates in the northeastern United States, in a sample of 42 eggs, were between March 14 and May 30. Additional records in southern Canada show laying as occurring at as late as June 5. 43 eggs in Ontario were laid between March 19 to May 24, more than half between April 15 and May 5. In northern Italy, the mean egg laying date was March 27. Exceptional eggs were recorded as early as December 31 to January 3 in Spain. Re-nesting can occur within about 20 days after a clutch is lost. In Europe up to two broods have been successfully been raised at times of food abundance. Generally the female lays 3-5 eggs (sometimes more if food is unusually abundant).  Larger clutches are typical further north in the range. Record sized clutches have been recorded for Europe of up to 8 eggs in Sweden in years of a “vole plague” while record sized clutches worldwide were recorded of 10–11 in the Kazan area of Russia in similar conditions. In Great Britain, the average clutch size was recorded as 3.9 while in Germany it was 5.5 and, similarly, in Slovenia it was 5.6. In a study from Montana, the mean clutch size was 5. The pure white eggs are 40.2 mm × 32.5 mm (1.58 in × 1.28 in) on average in both North America and central Europe and weight about 23 g (0.81 oz). At 1-5 day intervals (on average 2), the eggs are laid on the bottom of nesting area. A clutch of 7 eggs takes 10 to 11 days to lay. Incubation begins with the first egg and continues for about 27–28 days (in extreme cases from about 21 to 30 days). The female alone incubates while the male provides food, which is brought direct to nest. She may leave the nest early on to feed but does so much less later into incubation. A study in Montana found that corticosterone levels were considerably higher in adults of both sexes during the breeding season than during the non-breeding season, suggesting that the breeding season is more stressful on the owls.
The young hatch at 2 day intervals at any point between very late April and June. The average weight of 52 hatchlings in Montana was 18.4 g (0.65 oz). Their eyes open at 5–7 days (averaging 6.4 days in Montana) and they are brooded by the mother for about 2 weeks, often while the male perches nearby and watches over. The female alone feeds the chicks. In Idaho, the male was recorded to 2.5 times more prey deliveries during nesting than did the female. Injury feigning displays have been recorded at the nestling stage as an anti-predation measure. Usually long-eared owls are less bold in nest defense than some other owls, Strix owls for example, but they are capable of fierce protective attack nonetheless. Nesting defense by parents increased in Italy further into breeding season, with older nestlings being defended more vigorously. Females do a majority of nest defenses. Owl pairs incurring higher levels of regular disturbance are more likely to have a milder nest defense. During a defensive display, the parent ruffles up their plumage and partially spreads the wings to half open, trampling from one foot to the other, hissing and bill snapping and can look surprisingly large in this posture. If a perceived threat continues towards the owls, they may leap up and try to rake and grab at the threat with their talons. Even animals as large as humans may find themselves the victim of long-eared owl defensive attacks if they approach or, especially, if they climb up to a nest. The young leave the nest at 20–27 days of age (average about 22 days) but are initially flightless, often climbing about surrounding branches. At this stage they may be referred to as "branchers". Quite often the young fall to the ground, but they are usually able to climb back up using their claws and bill with heavy wing flapping. At dusk the begging branchers call to their parents with high pitched notes to indicate their location. At about 35–37 days, they are fully fledged and can fly well, but they often follow their parents and are fed by them for up to about 2 months, continuing to make high pitched calls. In Slovenia, independence was gained about 50–80 days after hatching, while in Idaho it was about 45 to 56 days.
Normally in North  America the species produces one clutch per year, but 2 clutches in a year have been recorded in high vole years. An exceptional double brood was recorded in Idaho due to high food availability, allowing the pair to successfully raise all 11 nestlings to fledgling, while in same season 3 other females in same grove were able to produce an average of 5.3 fledglings in their single broods. Like other species using open nests, rather than enclosed cavities, the species has relatively short fledging period and quickly moves away from the dangerous situation of the nest site. Nesting success averaged 46% between two study years in a study of 112 nests in Idaho with raccoon predation considered the most serious cause of nesting failure. A different Idaho study of 24 nests showed that the owls fledged an average of 3.7 young per nest. In Montana, the mean number hatched per nest was 3.8 and mean number to have fledged per nest was approximately 2.2. 59% of 78 nesting attempts failed in Britain, with an average clutch size per successful pair of 3.91 to 4.53. 41 of 78 continuously monitored in this British study nest successfully produced 1 or more fledglings.  In another British study, of 58 monitored pairs over 4 years, 83% laid eggs, 63% hatched one or more young, and 57% fledged young, with an average of 3.2 young fledged per successful nest. In yet another English study, this time exclusively of owls using wicker baskets, 50.7% of 71 attempts managed to fledge young. Among the wicker basket users, earlier nesters (i.e. March-early April) raised larger broods and had more fledglings than later (late April-early May), in part due to rising water tables making prey capture less ideal later in nesting season. For 6 pairs of long-eared owls using wicker baskets in Israel, the mean brood size was 3.6 and mean number of young owls to leave the nest was 3. At all stages and in all regions, reproduction tends to be more successful when prey populations are higher. In continental Europe, conditions are better than in England or Finland, perhaps due to the large population of common voles there that are absent in the more northerly countries, and nesting success averages higher. However, breeding success still is reliant on prey populations. In an 15 km² (5.8 sq mi) area of southern Germany, one cold spring with few voles no breeding pairs were found. A year later, with a warm spring and many voles, 19 breeding pairs took up residence in the study area. First year mortality of long-eared owls has been calculated in Germany as 52% and 31%. In Brandenburg, Germany, of 867 breeding attempts, 36.6% (335) pairs were successful in raising 1,468 young, which equates to 1.57 fledgling per all pairs that attempted, 4.31 per successful pair. The Brandenburg data shows that after 1990, when conservation minded farming initiative began, numbers increased significantly. Also in Brandenburg, in one case, 2 successive females to the same male were killed, the male mate was able to pair with a third female and resulting in a late successful fledging (August 24). In Slovenia, as studied between 1984 and 1993, of 79 nests, 32 (40%) produced young, 37 (47%) failed completely, and 10 (12%) failed after hatching. The Slovenian average number of owls hatched was 2.4 per nest (5.3 per successful nest) and the average number of owls fledged was 1.6 per nest (3.9 per successful nest). In Pisa, Italy, long-eared owl pairs produced a mean of 0.95 per territorial pair and 2.13 per successful pair. In central Slovenia, 57 nests produced an average of 5.7 eggs per clutch. Of the 51 fledged owls, 31 died in the study, 22 of which were due to mammal and bird predation, 6 due to starvation, 2 due to road collisions and 1 drowned in ditch. In Britain, the most common diagnosed cause of nest failure was egg theft by humans (accounting for 28.2% of 46 failed nests). Banding studies show that the long-eared owl typically have a short lifespan, with more than 91% of 105 owls recovered in North America of determined age being 4 years or younger. The oldest recorded in these efforts was banded in New York and recovered in Ontario at the age of 11 years and 4 months. Another one may have been over 15 years old, however. One exceptional isolated record is known of a European long-eared owl of just under 28 years of age. Annual survivorship in Germany and Switzerland for adults is 69%.


The long-eared owl is rather common and widespread in many regions. With a range of 80 million square kilometers, it is easily one of the most widely found owls. The IUCN estimates the total population between 2 million and 5.5 million, placing it as one of the most numerous owls beyond the wider ranging barn owl and less wide-ranging little owl (both likely between 5 and 10 million total birds) and roughly equaling the total population of great horned owls. The long-eared owl is more numerous than its more scarce but more wide-ranging cousin, the short-eared owl, with the peak number possible of short-ears roughly equivalent to the minimum number of long-ears. Their range of limit for breeding is typically in Mediterranean type arid, hot climates, where terrestrial insects and reptiles may prevail over small, sociable rodents, the long-eared owl is cut-off, whereas these are peak areas for barn owls. In the north, it is scarce to absent in areas of the deep boreal forest and the treeless northern areas such as around large wetland bogs or lower tundra, where the short-eared owl tends to supplant them. Densities of populations depend on availability of food. Local threats are typically pesticides and persecution. Out of myth and ignorance, this species has long been persecuted by humans. In many areas, some humans may carelessly shoot at any crow-like nest in order to destroy the contents, out of resentment for the crow's perception as a pest. In North America, hunters historically often shot long-eared owls as all owls were badly persecuted. Even though it was perceived early in the 20th century that the species is actually beneficial to human interests, many hunters continued to shoot them, claiming that they represent young individuals of the then nationally despised great horned owl. Largely in correlation with persecution, long-eared owls were recorded as formerly abundant and then rare in North America in the early 20th century. Long-eared owl potentially face lethal contamination with heavy metals such as mercury, organic biocides, including insecticides, fungicides and rodenticides and PCBs recorded. Pesticides seem to effect the species less than those predators with more varied diets and those that eat carrion. High levels of contamination were found in long-eared owl pellets in Serbia, with the concentrations of pollutants in prey that are sourced from industrial and agricultural practices in the region. Like many birds, they may be vulnerable to helminths, which are probably underrated as a potential source of mortality. Other parasites and mites may reduce health of populations. West Nile virus and Salmonella has been the recorded source of mortality for some long-eared owls. Anticoagulants may also threaten this species. In the Canary islands, it has become increasingly scarce due to loss of habitat. Many long-eared owls are also killed by road traffic. High owl mortality were particularly noted along roadways in France, especially due to high common vole numerous in roadside areas, proposed that letting vegetation grow may mitigate some mortalities. During 1963–1995, 128 dead long-eared owls turned in England, 89 were females and 34 were males. 61% turned had died from collisions (40% from those with vehicles). In this study from England, high levels of DDE (metabolite of DDT) and HEOD found in long-eared owls prior to 1977, similar levels to those seen in falcons there, lessened in later samples but 2 birds still had fatal levels of pesticide contamination. In areas such as Switzerland, to offset persecution and increase survival as well as to allow observers to watch them more easily, wintering owls in towns and cities were fed daily white lab mice. Breeding can be promoted by artificial platforms of twigs in bushes or trees. Also augmented feeding may ensure survival during low food winters. An attempt to release captive raised long-eared owl in the wild in Italy was largely unsuccessful. Of these, 3 of 8 attempted owls seemed to disperse successfully while the others died or disappeared, while 8 tawny owls released all but 1 seemed to successfully disperse. The species has actually increased in Iran, rising from 25 records over 12 decades to 49 records in two decades (between late 70s and 1997). Now breeding confirmed in up to 12 regions for the Persian breeding population and between 1997-2014 there were 32 non-breeding and 17 breeding records.
In southern California (San Diego county and Orange county), long-eared owls are thought to have lost more than 55% of their range due to habitat alterations. A decreasing trend has been observed in wintering owls in New Jersey, with 9 of 58 known roosts entirely eliminated due to land development, while the remaining 49 have shown reductions or are no longer used over the course of 30 years. Land use changes and habitat destruction accounts for reduced habitat quality and lower vole populations, with more adaptable raptors such as great horned owls and hawks exploiting much of what remains to the detriment of long-eared owls. A similar reduction was noted over 20 years in Pennsylvania. Broader studies of banding across Canada, gathered during long term monitoring from consistent annual bird counts from 1966–1992, showed that long-eared owl has declined relatively significantly. A net total 0.98% decline was recorded over the survey time. This was considered the second greatest reduction behind short-eared owl and burrowing owl (Athene cunicularia), furthermore among the 19 raptors surveyed in Canada, these 3 owls showed the most declining trends. The long-eared owl was apparently the most scarce of the 6 sub-boreal owl species surveyed. A similar trend has been detected throughout North America with a very large net 1.6% reduction overall during Christmas Bird Counts (CBC), again making it the most severe decline for an owl behind only the short-eared owl and the two related owl species seemed to have had the most severe declines of all 28 raptor species mentioned in these CBC surveys.


Asparagus aethiopicus, Sprenger's asparagus, is a plant native to the Cape Provinces and the Northern Provinces of South Africa. Often used as an ornamental plant, it is considered an invasive weed in many locations. Asparagus fern, asparagus grass and foxtail fern are common names; however, it is unrelated to true ferns. A. aethiopicus has been confused with A. densiflorus, now regarded as a separate species, so that information about A. aethiopicus will often be found under the name A. densiflorus.


Asparagus aethiopicus is native to southern regions of South Africa, mainly in the Western Cape, Eastern Cape and the Northern Provinces.
Its natural habitat is rocky shale slopes and coastal scrub, in relatively dry areas.
In the United States, it has been declared a weed in Hawaii, and Florida. It has also been declared a weed in New Zealand, and has become established around major urban areas in Australia including Sydney, Wollongong, the Central Coast, Southeastern Queensland, and Adelaide, as well as Lord Howe Island and Norfolk Island. Seeds are spread by fruit-eating birds and improper disposal of garden refuse. The pied currawong is a culprit in Sydney. It can be eradicated using various herbicides depending on the situation, or manual removal of the woody crown found at the junction between the leaves and roots, the non-reproductive water storage tubers can be safely left in the ground to decompose .


Asparagus aethiopicus is grown as an indoor plant in cooler climates, or as an ornamental garden plant in urban gardens, rockeries or in pots. Two cultivars are seen in cultivation, 'Sprengeri' is a scrambling form with sparser foliage, while 'Meyeri' has more erect stems to 70 cm (28 in) and denser foliage.
Consuming the berries of A. aethiopicus can cause gastrointestinal symptoms such as diarrhea, vomiting and abdominal pain, and contact with the skin may cause dermatitis. The plant is toxic to domestic cats and dogs.


Asparagus is a herbaceous, perennial plant growing to 100–150 centimetres (40–60 inches) tall, with stout stems with much-branched, feathery foliage. The 'leaves' are in fact needle-like cladodes (modified stems) in the axils of scale leaves; they are 6–32 millimetres (1⁄4–1+1⁄4 inches) long and 1 mm (1⁄32 in) broad, and clustered four to 15 together, in a rose-like shape. The root system, often referred to as a 'crown', is adventitious and the root type is fasciculated. The flowers are bell-shaped, greenish-white to yellowish, 4.5–6.5 mm (3⁄16–1⁄4 in) long, with six tepals partially fused together at the base; they are produced singly or in clusters of two or three in the junctions of the branchlets. It is usually dioecious, with male and female flowers on separate plants, but sometimes hermaphrodite flowers are found. The fruit is a small red berry 6–10 mm (1⁄4–13⁄32 in) in diameter, which is toxic to humans.
Plants native to the western coasts of Europe (from northern Spain to northwest Germany, north Ireland, and Great Britain) are treated as Asparagus officinalis subsp. prostratus (Dumort.) Corb., distinguished by its low-growing, often prostrate stems growing to only 30–70 centimetres (12–28 in) high, and shorter cladodes 2–18 mm (3⁄32–23⁄32 in) long. It is treated as a distinct species, Asparagus prostratus Dumort, by some authors.


Certain compounds in asparagus are metabolized to yield ammonia and various sulfur-containing degradation products, including various thiols and thioesters, which following consumption give urine a characteristic smell.
Some of the volatile organic compounds responsible for the smell are:
methanethiol
dimethyl sulfide
dimethyl disulfide
bis(methylthio)methane
dimethyl sulfoxide
dimethyl sulfone
Subjectively, the first two are the most pungent, while the last two (sulfur-oxidized) give a sweet aroma. A mixture of these compounds form a "reconstituted asparagus urine" odor.  This was first investigated in 1891 by Marceli Nencki, who attributed the smell to methanethiol. These compounds originate in the asparagus as asparagusic acid and its derivatives, as these are the only sulfur-containing compounds unique to asparagus. As these are more present in young asparagus, this accords with the observation that the smell is more pronounced after eating young asparagus. The biological mechanism for the production of these compounds is less clear.
The onset of the asparagus urine smell is remarkably rapid while the decline is slower. The smell has been reported to be detectable 15 to 30 minutes after ingestion and subsides with a half-life of approximately four hours.


A. officinalis is widely known simply as "asparagus", and may be confused with unrelated plant species also known as "asparagus", such as Ornithogalum pyrenaicum known as "Prussian asparagus" for its edible shoots.
The English word "asparagus" derives from classical Latin but the plant was once known in English as sperage, from the Medieval Latin sparagus. This term itself derives from the Greek aspharagos or asparagos, but the Greek terms are of uncertain provenance: the latter form admits the possibility of a Proto-Indo-European root meaning "to jerk, scatter," directly or via a Persian descendant meaning "twig, branch"; but the Ancient Greek word itself, meaning "gully, chasm," seems to be of Pre-Greek origin instead.
Asparagus was corrupted in some places to "sparrow grass"; indeed, John Walker wrote in 1791 that "Sparrowgrass is so general that asparagus has an air of stiffness and pedantry".
The name 'sparrow grass' was still in common use in rural East Anglia, England well into the twentieth century.
In Turkish, asparagus is known as kuşkonmaz, literally "[a] bird won't land [on it]", in reference to the shape of the plant.


Only young asparagus shoots are commonly eaten: once the buds start to open ("ferning out"), the shoots quickly turn woody. The roots contain starch.
Water makes up 93% of asparagus's composition. Asparagus is low in food energy and very low in sodium. It is a good source of vitamin B₆, calcium, magnesium, and zinc, and a very good source of dietary fibre, protein, beta-carotene, vitamin C, vitamin E, vitamin K, thiamin, riboflavin, rutin, niacin, folic acid, iron, phosphorus, potassium, copper, manganese, and selenium, as well as chromium, a trace mineral that regulates the ability of insulin to transport glucose from the bloodstream into cells. The amino acid asparagine gets its name from asparagus, as the asparagus plant is relatively rich in this compound.
The shoots are prepared and served in a number of ways around the world, typically as an appetizer or vegetable side dish. In Asian-style cooking, asparagus is often stir-fried.  Cantonese restaurants in the United States often serve asparagus stir-fried with chicken, shrimp, or beef. It may also be quickly grilled over charcoal or hardwood embers, and is also used as an ingredient in some stews and soups. In recent years, asparagus eaten raw as a component of a salad has regained popularity, although may cause digestive issues for some.
Asparagus can also be pickled and stored for several years. Some brands label shoots prepared in this way as "marinated".
Stem thickness indicates the age of the plant (and not the age of the stalk), with the thicker stems coming from older plants. Older, thicker stalks can be woody, although peeling the skin at the base removes the tough layer. Peeled asparagus will poach much faster. The bottom portion of asparagus often contains sand and soil, so thorough cleaning is generally advised before cooking.  Plants bearing seeds produce spears that are smaller and thinner, and plants without seeds produce larger and thicker spears.  Thickness and thinness are not an indication of tenderness or toughness.  The stalks are thick or thin from the moment they sprout from the ground.
Green asparagus is eaten worldwide, and the availability of imports throughout the year has made it less of a delicacy than it once was. In Europe, according to one source, the "asparagus season is a highlight of the foodie calendar"; in the UK this traditionally begins on 23 April and ends on Midsummer Day. As in continental Europe, due to the short growing season and demand for local produce, asparagus commands a premium price.


The top asparagus importers (2016) were the United States (214,735 tonnes), followed by Germany (24,484 tonnes), and Canada (19,224 tonnes).
China is by far the world's largest producer: in 2017 it produced 7,845,162 tonnes, followed by Peru with 383,098 tonnes and Mexico with 245,681 tonnes. U.S. production was concentrated in California, Michigan, and Washington.
The annual production for white asparagus in Germany is 57,000 tonnes (61% of consumer demand).
When grown under tunnels, growers can extend the harvest season. In the UK, it is estimated that the asparagus harvest season can begin as early as mid-February and continue into late autumn by growing cold-resistant cultivars under heated polytunnels. Furthermore, late season harvests can be achieved using 'reverse season growth' where spears are left to fern between March–August and harvested in September–October.
In Asia, an alternative approach to cultivating asparagus has been employed and is referred to as 'Mother Stalk Method' where three to five stalks per plant are allowed to develop into fern, while harvesting adjacent spears.


White asparagus is very popular in Europe and western Asia. White asparagus is the result of applying a blanching technique while the asparagus shoots are growing. To cultivate white asparagus, the shoots are covered with soil as they grow, i.e. earthed up; without exposure to sunlight, no photosynthesis starts, and the shoots remain white. Compared to green asparagus, the locally cultivated so-called "white gold" or "edible ivory" asparagus, also referred to as "the royal vegetable", is believed to be  less bitter and much more tender. Freshness is very important, and the lower ends of white asparagus must be peeled before cooking or raw consumption.
Only seasonally on the menu, asparagus dishes are advertised outside many restaurants, usually from late April to June. For the French style, asparagus is often boiled or steamed and served with Hollandaise sauce, White sauce, melted butter or most recently with olive oil and Parmesan cheese. Tall, narrow asparagus cooking pots allow the shoots to be steamed gently, their tips staying out of the water.
During the German Spargelsaison or Spargelzeit ("asparagus season" or "asparagus time"), the asparagus season that traditionally finishes on 24 June, roadside stands and open-air markets sell about half of the country's white asparagus consumption.
In western Himalayan regions, such as Nepal and north-western India wild asparagus is harvested as a seasonal vegetable delicacy known as Kurilo	or Jhijhirkani.


Asparagus has been used as a vegetable owing to its distinct flavor, and in medicine due to its diuretic properties and its purported function as an aphrodisiac. It is pictured as an offering on an Egyptian frieze dating to 3000 BC. In ancient times, it was also known in Syria and in the Iberian Peninsula. Greeks and Romans ate it fresh when in season, and dried the vegetable for use in winter. Emperor Augustus coined the expression "faster than cooking asparagus" for quick action.
A recipe for cooking asparagus is given in one of the oldest surviving collections of recipes (Apicius's 1st century AD De re coquinaria, Book III). In the second century AD, the Greek physician Galen, highly respected within Roman society, mentioned asparagus as a beneficial herb, but as dominance of the Roman empire waned, asparagus' medicinal value drew little attention
until al-Nafzawi's The Perfumed Garden. That piece of writing celebrates its purported aphrodisiacal  power that the Indian Ananga Ranga attributes to "special phosphorus elements" that also counteract fatigue.
By 1469, asparagus was cultivated in French monasteries. Asparagus appears to have been little noticed in England until 1538, and in Germany until 1542.
Asparagus was brought to North America by European settlers at least as early as 1655. Adriaen van der Donck, a Dutch immigrant to New Netherland, mentions asparagus in his description of Dutch farming practices in the New World. Asparagus was grown by British immigrants as well; in 1685, one of William Penn's advertisements for Pennsylvania included asparagus in a long list of crops that grew well in the American climate.
The points d'amour ("love tips") were served as a delicacy to Madame de Pompadour (1721–1764).


The green crop is significant enough in California's Sacramento–San Joaquin River Delta region that the city of Stockton holds a festival every year to celebrate it. Oceana County, Michigan, the self-proclaimed "asparagus capital of the world" hosts an annual festival complete with a parade and asparagus queen;  The Vale of Evesham in Worcestershire is the largest producer within Northern Europe, celebrating with the annual British Asparagus Festival involving auctions of the best crop, an "Asparagus Run" modelled on the Beaujolais Run and a weekend "Asparafest" music festival.
Many German cities hold an annual Spargelfest (asparagus festival) celebrating the harvest of white asparagus. Schwetzingen claims to be the "Asparagus Capital of the World", and during its festival, an Asparagus Queen is crowned. The Bavarian city of Nuremberg feasts a week long in April, with a competition to find the fastest asparagus peeler in the region; this usually involves generous amounts of the local wines and beers being consumed to aid the spectators' appreciative support.
Helmut Zipner, who peeled a ton of asparagus in 16 hours, holds the world record in asparagus peeling.


This fine, delicate looking creeper is actually quite hardy. It prefers shady areas and moisture, but can tolerate some drought. Its soft, feathery foliage is a deep, rich green and unlike other asparagus ferns, this species does not grow thorns.


This tough little creeper is indigenous to the shady afro-montane forests of the Western Cape, South Africa. Here it can be found from the indigenous woods and kloofs of Cape Town, eastwards as far as the Tsitsikamma Mountains.
Cultivated in South African gardens, it is a very useful ornamental plant for growing in deep shade. It will climb up any sticks, pillars or trellises that are available, but if there is nothing for it to climb up, it will simply form a thick, feathery groundcover.
It grows many tiny white drooping flowers that are followed by little orange fruits. These attract birds which help to disperse them.
It is best propagated from seed.
A. scandens is an invasive species in some countries. In New Zealand it is listed on the National Pest Plant Accord, which means that it cannot be sold or distributed. In Australia it is listed on the Weeds of National Significance, a list of 32 taxa compiled by the federal government.


Asphodelus ramosus is a geophyte, having an underground storage organ which enables the plant to survive adverse conditions, such as excessive heat and drought. Its leaves, growing to a height of 60 centimetres (24 in)–80 centimetres (31 in), contain alkaloids that are harmful to sheep and goats in the wet, winter months, but during the summer when their leaves dry out, they lose their toxicity. Its very numerous flowers are white with six tepals bearing a central brown streak. The fruits are small round capsules.


The Chihuahuan spotted whiptail (Aspidoscelis exsanguis) is a species of lizard native to the United States in southern Arizona, southern New Mexico and southwestern Texas, and northern Mexico in northern Chihuahua and northern Sonora.
The species is believed to be the result of extensive hybridization between the little striped whiptail, Aspidoscelis inornatus, the plateau spotted whiptail, Aspidoscelis septemvittatus, and the western Mexico whiptail, Aspidoscelis costatus. It is one of many lizard species known to be parthenogenetic.


The six-lined racerunner is found throughout much of the southeastern and south-central portion of the United States, from Maryland to Florida in the east, across the Great Plains to southern Texas and northern Mexico.  In a study conducted on A. sexlineata in Mexico, the majority of the individuals found were inhabiting areas near the seashore that were formed and influenced from maritime climate and hurricanes. The species' range also reaches north to Wisconsin and Minnesota. A small disjunct population is found in Tuscola County, Michigan.


The six-lined racerunner is typically dark green, brown, or black in color, with six yellow or green-yellow stripes that extend down the body from head to tail. The underside is usually white in color on females, and a pale blue in males. Males also sometimes have a pale green-colored throat. They are slender-bodied, with a tail nearly twice the body length.


Like other species of whiptail lizards, the six-lined racerunner is diurnal and insectivorous. The principal foods of A. sexlineata are spiders (Araneae 16.8%), grasshoppers (orthoptera 16.8%), and leaf hoppers (Homoptera 14.1%). They are wary, energetic, and fast moving, with speeds of up to 18 mph (29 kmh), darting for cover if approached. Aggressive behavior is common, as the dominant will chase the subordinate and often follow up with a bite to signify dominance.


Due to its extensive range, A. sexlineata is found in a wide variety of habitats including grasslands, woodlands, open floodplains, or rocky outcroppings. Populations have also been found abundantly in areas that experience frequent fires. It prefers lower elevations, with dry loamy soils. In the lower elevations, the six-lined racerunner can be found in human-made disturbances like under voltage towers or along highways and railroads.


The Sonoran spotted whiptail (Aspidoscelis sonorae) is a parthenogenic species of teiid lizard found in Arizona and New Mexico in the United States, and Mexico.


The western whiptail (Aspidoscelis tigris) is a species of lizard in the family Teiidae. The species ranges throughout most of the southwestern United States and northern Mexico. Most of its populations appear stable, and it is not listed as endangered in any of the states comprising its range.  It lives in a wide variety of habitats, including deserts and semiarid shrubland, usually in areas with sparse vegetation; it also may be found in woodland, open dry forest, and riparian growth. It lives in burrows. Major differences between this species and the checkered whiptail (Aspidoscelis tesselatus) include the lack of enlarged scales anterior to the gular fold and the presence of enlarged postantebrachial scales.  It was previously known as Cnemidophorus tigris, until phylogenetic analyses concluded that the genus Cnemidophorus was polyphyletic. Since it does not migrate, a number of forms have developed in different regions, several of which have been given subspecific names – for example the California whiptail, Aspidoscelis tigris munda.


The western whiptail is widespread throughout northern Mexico and the western United States. In the US it can be found in the states of Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, and Utah. It is found in hot dry regions, typically with sparse foliage. It can live in woodland, chaparral, riparian areas, or desert. Desert subspecies prefer habitat with vegetation such as sagebrush or shadscale, and rely on burrows to escape the desert heat.
In the northern parts of its range, the western whiptail usually emerges from hibernation in May, and most adults aestivate during the midsummer months, but in the south it is active from April through late August. The seasonal period of activity is therefore considerably shorter in the north. Daily periods of activity are of similar duration from north to south, although the time of emergence tends to be later in northern areas.


The western whiptail's chromosomes show that it is polyploid. It is also a bisexual species, containing both males and females, unlike other species of Aspidoscelis which are all-female. Usually in the northern end of its range, mating occurs in the first half of June, and females begin to lay eggs in late June. The eggs usually begin hatching by mid-August. Females will only lay one clutch (number of eggs laid at a single time) per year. At the southern end of its range, however, females will begin to lay eggs as early as May, and the eggs will usually hatch as early as mid-June. In the southern end of its range, females may also lay two clutches per year instead of just one.


The western whiptail mostly eats insects, spiders, scorpions, lepidopterans, crickets, grasshoppers, and beetles. They use their jaws instead of their tongue to capture their prey.


Asplenium appendiculatum is rare in Victoria. It has been observed in the Victoria Range, Mt Mueller and Wilsons Promontory.


Asplenium montanum, commonly known as the mountain spleenwort, is a small fern endemic to the eastern United States. It is found primarily in the Appalachian Mountains from Vermont to Alabama, with a few isolated populations in the Ozarks and in the Ohio Valley. It grows in small crevices in sandstone cliffs with highly acid soil, where it is usually the only vascular plant occupying that ecological niche. It can be recognized by its tufts of dark blue-green, highly divided leaves. The species was first described in 1810 by the botanist Carl Ludwig Willdenow. No subspecies have been described, although a discolored and highly dissected form was reported from the Shawangunk Mountains in 1974. Asplenium montanum is a diploid member of the "Appalachian Asplenium complex," a group of spleenwort species and hybrids which have formed by reticulate evolution. Members of the complex descended from A. montanum are among the few other vascular plants that can tolerate its typical habitat.


Asplenium montanum readily forms hybrids with a number of other species in the "Appalachian Asplenium complex". In 1925, Edgar T. Wherry noted the similarities between A. montanum, lobed spleenwort (A. pinnatifidum), and Trudell's spleenwort (A. × trudellii), and in 1936 concluded that Trudell's spleenwort was a hybrid between the first two. In 1951, Herb Wagner, while reviewing Irene Manton's Problems of Cytology and Evolution in the Pteridophyta, suggested in passing that A. pinnatifidum itself might represent a hybrid between A. montanum and the American walking fern, Camptosorus rhizophyllus (now A. rhizophyllum).
In 1953, he reported preliminary cytological studies on the Aspleniums and suggested that A. montanum had crossed with ebony spleenwort (A. platyneuron) to yield Bradley's spleenwort (A. bradleyi), noting that D. C. Eaton and W. N. Clute had already made tentative suggestions along those lines. He also made chromosome counts of A. × trudellii, which had been classified by some simply as a variety of A. pinnatifidum. As A. pinnatifidum proved to be a tetraploid while A. montanum was a diploid, a hybrid between them would be a triploid, and Wagner showed that this was in fact the case for A. × trudellii. His further experiments, published the following year, strongly suggested that both A. bradleyi and A. pinnatifidum were allotetraploids, the product of hybridization between A. montanum and another Asplenium to form a sterile diploid, followed by chromosome doubling that restored fertility.
These cytotaxonomic findings were supported by subsequent chromatographic studies. A. montanum was shown to produce a pattern of seven substances chromatographically distinct from those produced by the other diploid members of the Appalachian Asplenium complex. These substances were present in the chromatograms of all tested hybrids believed to descend from A. montanum at one or more removes: A. bradleyi, A. × gravesii, A. × kentuckiense, A. pinnatifidum, A. × trudellii, and A. × wherryi. Four of the compounds present in the chromatograms of A. montanum and its descendants, fluorescing gold-orange under ultraviolet light, were subsequently identified as the xanthonoids mangiferin, isomangiferin, and their O-glucosides. The other two were identified as kaempferol derivatives, but could not be more precisely determined due to lack of material; the last was a trace compound which could not be studied. A chloroplast phylogeny has suggested that A. montanum is the maternal ancestor of A. bradleyi.
The allotetraploid hybrid species derived from A. montanum can backcross with A. montanum to form triploid hybrids. The backcross hybrid between A. montanum and A. pinnatifidum is A. × trudellii, as suggested by Wherry. He also collected specimens of the backcross hybrid between A. montanum and A. bradleyi from a cliff near Blairstown, New Jersey in 1935. The hybrid received no further attention until 1961, when it was described and named in Wherry's honor as Wherry's spleenwort (A. × wherryi). The sterile diploid A. montanum × platyneuron, precursor to A. bradleyi, was collected in 1972 at Crowder's Mountain, Georgia; A. montanum × rhizophyllum, precursor to A. pinnatifidum, has never been found.


One of the "Appalachian spleenworts", A. montanum is found in the Appalachian Mountains from Vermont and Massachusetts southwestward to Tennessee, Alabama, and Georgia, and to a lesser extent in the Ohio Valley in Ohio, Indiana, and Kentucky. Arkansas populations were discovered in Garland County and Stone County in 2002 and 2008, respectively. One outlying population in Missouri, collected in 1960, is considered historical; it is represented by one specimen collected near Graham Cave and has never been relocated. The site is thought to have been destroyed by road construction. A collection by Farwell from the Keweenaw Peninsula of Michigan was considered valid by M. L. Fernald, but is of questionable authenticity; the population has never been relocated.
Asplenium montanum grows on acidic rocks such as sandstone, in crevices into which moisture seeps from within the rock strata. It has been found at altitudes up to 2,000 meters (7,000 ft). Like the closely related A. bradleyi, A. montanum requires that the thin soil in its favored crevices be subacid (pH 4.5–5.0) to mediacid (pH 3.5–4.0), and it is intolerant of calcium. This habitat is unfavorable to most other plants, but its allotetraploid descendants and their backcross hybrids may occur alongside it.


Asplenium montanum is globally secure, but threatened at the edges of its range. It is known only historically from Missouri, and NatureServe considers it critically imperiled in Indiana, Massachusetts, Rhode Island, and Vermont, imperiled in New Jersey, and imperiled to vulnerable in Connecticut and New York. The principal threat to New York populations is rock climbing.


Asplenium nidus is native to east tropical Africa (in Tanzania, inclusive of the Zanzibar Archipelago); temperate and tropical Asia (in Indonesia; East Timor; the island of Kyushu, and the Ryukyu Islands of Japan; Malaysia; the Philippines; Taiwan; and Thailand); and in Australasia (in the northern part of Queensland in Australia).


With a minimum temperature of 10 °C (50 °F), Asplenium nidus is widely cultivated in temperate regions as a houseplant. However, many plants sold in America as A. nidus are actually Asplenium australasicum, which has longer sori, and a differently shaped midrib.  Asplenium nidus has gained the Royal Horticultural Society's Award of Garden Merit.
Asplenium nidus has been used locally in folk medicine for asthma, sores, weakness, and halitosis.
The sprouts of A. nidus are eaten as a vegetable in Taiwan where it is called 山蘇 (pronounced shān sũ) and typically cut into inch-long pieces and sautéed with garlic and chilli peppers.


The principal range of A. rhizophyllum is in the Appalachian Mountains and the Ozarks. It can be found from southern Quebec and Ontario along the Appalachians and Piedmont southwestward to Mississippi and Alabama, along the Ohio Valley and into the Ozarks west to Nebraska and Oklahoma, and along the Mississippi Valley north to Wisconsin and Minnesota. It has become extinct in Maine and Delaware. The distribution typically follows area of limy soil; sometimes said to be rare, it is better described as locally abundant where conditions favor it.


Walking fern grows on shaded boulders, ledges and in crevices, usually covered with moss. On rare occasions, it is found on fallen tree trunks, as an epiphyte, or on the ground. It is usually found on limestone or other alkaline rocks, rarely on sandstone or other acidic rocks.
While globally secure, it is endangered in some states and provinces at the edge of its range. NatureServe considers it critically imperiled (S1) in Mississippi, New Hampshire and Rhode Island, imperiled (S2) in Michigan and South Carolina, and vulnerable (S3) in North Carolina and Quebec.


Asplenium ruta-muraria is native to Europe, East Asia, and eastern North America. In North America, its range extends from western New England southwest along the Appalachian Mountains to Alabama and Tennessee. It is also found in the Ozarks and in southern Indiana and Ohio, with outlying occurrences in Michigan, Ontario, Quebec, and Clinton County, Iowa.
In Europe, it commonly invades masonry and is a common species, while in the United States, it is more difficult to find, favouring pockets in very well-weathered and rather dry limestone outcrops.


Young specimens of A. hygrometricus have roughly spherical fruit bodies that typically start their development partially embedded in the substrate. A smooth whitish mycelial layer covers the fruit body, and may be partially encrusted with debris. As the fruit body matures, the mycelial layer tears away, and the outer tissue layer, the exoperidium, breaks open in a star-shaped (stellate) pattern to form 4–20 irregular "rays". This simultaneously pushes the fruit body above ground to reveal a round spore case enclosed in a thin papery endoperidium. The rays open and close in response to levels of moisture in the environment, opening up in high humidity, and closing when the air is dry. This is possible because the exoperidium is made of several different layers of tissue; the innermost, fibrous layer is hygroscopic, and curls or uncurls the entire ray as it loses or gains moisture from its surroundings. This adaptation enables the fruit body to disperse spores at times of optimum moisture, and reduce evaporation during dry periods. Further, dry fruit bodies with the rays curled up may be readily blown about by the wind, allowing them to scatter spores from the pore as they roll.
The fruit body is 1–8 cm (0.5–3 in) in diameter from tip to tip when expanded. The exoperidium is thick, and the rays are typically areolate (divided into small areas by cracks and crevices) on the upper surface, and are dark grey to black. The spore case is sessile (lacking a stalk), light gray to tan color and 1 to 3 cm (0.4 to 1.2 in) broad with a felt-like or scurfy (coated with loose scaly crust) surface; the top of the spore case is opened by an irregular slit, tear or pore. The interior of the spore case, the gleba, is white and solid when young, and divided into oval locules—a characteristic that helps to distinguish it from Geastrum. The gleba becomes brown and powdery as the specimen matures. Small dark hairlike threads (rhizomorphs) extend from the base of the fruit body into the substrate. The rhizomorphs are fragile, and often break off after maturity.
The spores are spherical or nearly so, reddish-brown, thick-walled and verrucose (covered with warts and spines). The spores' dimensions are 7–11 µm; the warts are about 1 µm long. The spores are non-amyloid, and will not stain with iodine from Melzer's reagent. The use of scanning electron microscopy has shown that the spines are 0.90–1.45 µm long, rounded at the tip, narrow, tapered, and sometime joined at the top. The capillitia (masses of thread-like sterile fibers dispersed among the spores) are branched, 3.5–6.5 µm in diameter, and hyaline (translucent). The basidia (spore-bearing cells) are four- to eight-spored, with very short sterigmata. The basidia are arranged in long strings of clusters; individual basidia measure 11–15 by 18–24 µm. The threads of the capillitia arise from the inner surface of the peridium, and are thick-walled, long, interwoven, and branched, measuring 3–5.5 µm thick. The exoperidium (the outer layer of tissue, comprising the rays) is made of four distinct layers of tissue: the mycelial layer contains branched hyphae that are 4–6 μm in diameter; the hyphae of the fibrous layer are 6–8 μm diameter and branched; the collenchyma-type layer has branched hyphae of 3–4 μm diameter; the soft layer contains hyphae that are 3–6 μm in diameter.


Astraeus hygrometricus is an ectomycorrhizal fungus and grows in association with a broad range of tree species. The mutualistic association between tree roots and the mycelium of the fungus helps the trees extract nutrients (particularly phosphorus) from the earth; in exchange, the fungus receives carbohydrates from photosynthesis. In North America, associations with oak and pine are usual, while in India, it has been noted to grow commonly with chir pine (Pinus roxburghii) and sal (Shorea robusta). The false earthstar is found on the ground in open fields, often scattered or in groups, especially in nutrient-poor, sandy or loamy soils. It has also been reported to grow on rocks, preferring acid substrates like slate and granite, while avoiding substrates rich in lime. In Nepal, fruit bodies have been collected at elevations of 3,000 m (9,800 ft). Fruit bodies typically appear in autumn, although the dry fruit bodies are persistent and may last up to several years. Gelatinipulvinella astraeicola is a leotiaceous fungus with minute, gelatinous, pulvinate (cushion-shaped) apothecia, known to grow only on the inner surface of the rays of dead Astraeus species, including A. hygrometricus.
The genus has a cosmopolitan distribution except for arctic, alpine and cold temperate regions; it is common in temperate and tropical regions of the world. It has been collected in Africa, Asia, Australia, Europe, North America, and South America.


Astragalus canadensis is a common and widespread member of the milkvetch genus in the legume family, known commonly as Canadian milkvetch. The plant is found throughout Canada and the United States in many habitats including wetlands, woodlands, and prairies. It sends out several thin, erect, green stems, bearing leaves that are actually made up of pairs of leaflets, each leaflet up to 3 centimeters in length. It has inflorescences of tubular, greenish-white flowers which yield beanlike fruits within pods that rattle when dry.
Like other Astragalus species, A. canadensis is somewhat toxic, but it has been used medicinally by Native American groups such as the Blackfoot and Lakota people, particularly the roots.


Astragalus purshii is a species of milkvetch known by the common names woollypod milkvetch and Pursh's milkvetch.


Astragalus purshii is a small perennial herb forming low matts on the ground no taller than 14 centimeters and generally less than 5 centimeters. The leaves are up to 15 centimeters long and are made up of many oval or rounded leaflets. Stems and leaflets are coated in woolly white hairs giving a silver color to the foliage.
The inflorescence is a cluster of 1 to 11 pink, rose, purple, or white flowers (depending on geographic location) each between 1 and 3 centimeters long. The fruit is a legume pod up to 3 centimeters long which is coated densely in thick white wooly hairs resembling a small rabbits-foot or cottonball.


This is an important plant for honeybees, butterflies and other insects. In southern Africa there are at least seven species of butterfly and moth that use A. g. micrantha as a larval foodplant; Junonia oenone, Junonia hierta, Junonia natalica, Junonia terea, Protogoniomorpha parhassus, Hypolimnas misippus  and Microplexia costimaculalis. The vigorous growth of A. g. micrantha in tropical regions makes it a weed which can smother certain indigenous vegetation where it has been introduced.