Instruct: Given a question, retrieve relevant documents that answer the question.
Query: What do water rails eat?
This rail forages in shallow water near cover and eats mainly aquatic insects and crustaceans. It forages by probing the mud while moving around in shallow water.
Superb fairywrens are predominantly insectivorous. They eat a wide range of small creatures (mostly insects such as ants, grasshoppers, shield bugs, flies, weevils and various larvae) as well as small quantities of seeds, flowers, and fruit. Their foraging, termed 'hop-searching', occurs on the ground or in shrubs that are less than two metres high. Because this foraging practice renders them vulnerable to predators, birds tend to stick fairly close to cover and forage in groups. During winter, when food may be scarce, ants are an important 'last resort' food, constituting a much higher proportion of the diet. Nestlings, in contrast to adult birds, are fed a diet of larger items such as caterpillars and grasshoppers.
The water rail is monogamous and highly territorial when breeding. The birds pair off after arriving at their nesting areas, or possibly even before spring migration. In large wetlands with good conditions birds may nest apart. Territories vary in size, but is typical. The pair give courting and contact calls throughout the breeding season. The male selects the nest site which he shows to the female while posturing with raised back feathers, wings arched over his back, tail spread and bill pointed vertically downwards. This display is accompanied by a loud call. Before mating, he raises his wings and tail, and bows with his bill touching his breast. The male feeds the female during courtship, and, when incubating, she may leave the nest to display to the male, walking round him, calling softly, rubbing her bill against his and taking short runs to and from him.
Black wildebeest are predominantly grazers, preferring short grasses, but also feeding on other herbs and shrubs, especially when grass is scarce. Shrubs can comprise as much as 37% of the diet, but grasses normally form more than 90%. Water is essential, though they can exist without drinking water every day. The herds graze either in line or in loose groups, usually walking in single file when moving about. They are often accompanied by cattle egrets, which pick out and consume the insects hidden in their coats or disturbed by their movements.
Rattlesnakes receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by. However, rattlesnakes fall prey to hawks, weasels, king snakes, and a variety of other species. Rattlesnakes are heavily preyed upon as neonates, while they are still weak and immature. Large numbers of rattlesnakes are killed by humans. Rattlesnake populations in many areas are severely threatened by habitat destruction, poaching, and extermination campaigns.
The mandrill is an omnivore. It usually consumes plants, of which it eats over a hundred species. It prefers to eat fruits, but will also eat leaves, lianas, bark, stems, and fibers. It also consumes mushrooms and soil. Carnivorously, mandrills mostly eat invertebrates, particularly ants, beetles, termites, crickets, spiders, snails, and scorpions. It will also eat eggs, and even vertebrates such as birds, tortoises, frogs, porcupines, rats, and shrews. Mandrills likely will eat larger vertebrates when they have the opportunity, such as juvenile bay duikers and other small antelope. Large prey are likely killed with a bite to the nape with the mandrill's long canines. One study found the mandrill's diet was composed of fruit (50.7%), seeds (26.0%), leaves (8.2%), pith (6.8%), flowers (2.7%), and animal foods (4.1%), with other foods making up the remaining (1.4%).
Their diet includes the fruit and seeds of local cactus plants, as well as beans of the mesquite plant. They do not only eat vegetation, and also consume insects, small rodents and carrion. They have a variety of predators including the bobcat, coyotes, as well as local snakes and domestic animals such as dogs and cats.
The Paridae are mainly small stocky woodland species with short stout bills. Some have crests. They are adaptable birds, with a mixed diet including seeds and insects.
The antelope jackrabbit feeds on cacti, grasses, and other leafy vegetation. This species has been observed digging and eating soil in an attempt to intake minerals and other nutrients. They can be classified as folivores and graminivores.
Jaws allow fish to eat a wide variety of food, including plants and other organisms. Fish ingest food through the mouth and break it down in the esophagus. In the stomach, food is further digested and, in many fish, processed in finger-shaped pouches called pyloric caeca, which secrete digestive enzymes and absorb nutrients. Organs such as the liver and pancreas add enzymes and various chemicals as the food moves through the digestive tract. The intestine completes the process of digestion and nutrient absorption.
A very large balance of the prey range can also be comprised by birds and other prey including reptiles, amphibians, fish, insects and other invertebrates are seemingly taken whenever they are available. All told, well more than 600 different species have been identified as prey of Eurasian eagle-owls. Their diet includes basically all the same prey as all sympatric diurnal raptors in the genera "Buteo", "Aquila" and "Haliaeetus". The total number of prey species may even surpass that of the great horned owl and may well be the greatest of any raptorial bird on the Eurasian continent. Among five segments of Europe the average prey diversity per region was 63 species, a higher number than any of the other 40 raptorial bird species studied there. The mean mass of prey per study has varied from as little as , near the now former Aral Sea in Turkmenistan with the Turkmen jerboa ("Jaculus turkmenicus") being the primary prey species, to , in Spain with the European rabbit being the primary prey species. Remarkably, in northern Spain, where the rabbit is now extirpated (as was the eagle-owl for a time in the 20th century), the average weight of prey can dip as low as . In comparison, the lightest mean prey mass in dietary studies of the great horned owl was while the highest was .
The Paridae are mainly small stocky woodland species with short stout bills. Some have crests. They are adaptable birds, with a mixed diet including seeds and insects. Four species have been recorded in Washington.Order: PasseriformesFamily: Aegithalidae
This is a bird which breeds in sub-tropical semi-desert with a few trees, such as acacia. It winters in open woodland or grassland. As the name suggests, bee-eaters predominantly eat insects, especially bees, wasps and hornets, which are caught in the air by sorties from an open perch. However, this species probably takes more dragonflies than any other food item. Its preferred hunting perch is telephone wires if available.
Throughout the western Mediterranean region, the Eurasian Eagle-Owl is something of a specialist on a single prey species: the European rabbit. The rabbit historically reached extremely high densities in Iberian scrub, i.e. more than 40 per every 1 square hectare (2471 square acres). In central Spain, up to 73.1% of the prey that were recorded for Eurasian eagle-owls, by number, can be rabbits. Where still available, they are also the main prey in Portugal and central France. However, following the devastation of the wild rabbit due to rabbit haemorrhagic disease, the local eagle-owls have frequently had to adapt to other, often smaller, prey. On the other hand, given the now much reduced numbers of rabbits, the eagle-owls still regularly select rabbits, seemingly out of proportion to their commonality. Although large mature wild rabbits commonly weigh , the eagle-owls usually hunt smaller specimens, often with an average weight around , with young rabbits usually selected in spring and summer and subadults selected in the autumn and winter. This is largely due to the behaviour of rabbits, with younger rabbits being forced to distribute following weaning, being less cautious in behaviour and occupying less primary habitat, thus being forced out of the confines of their burrows more regularly than mature adults. However, the estimated average weight of rabbits taken can be variable, reported from as little as in a study from Spain to as much as in the Netherlands.
As a highly opportunistic predator, the Eurasian eagle-owl will hunt almost any appropriately sized prey they encounter. Most often they take what ever prey is locally common and can take a large number of species considered harmful to human financial interests such as rats, mice and pigeons. Eurasian eagle-owls do take rare or endangered species as well. Among the species considered at least vulnerable (up to critically endangered as in the mink and eel, both heavily overexploited by humans) to extinction known to be hunted by Eurasian eagle-owls are Russian desman ("Desmana moschata") Pyrenean desman ("Galemys pyrenaicus"), barbastelle ("Barbastella barbastellus"), European ground squirrel ("Spermophilus citellus"), southwestern water vole ("Arvicola sapidus"), European mink ("Mustela lutreola"), marbled polecat ("Vormela peregusna"), lesser white-fronted goose ("Anser erythrops"), Egyptian vulture ("Neophron percnopterus"), greater spotted eagle ("Clanga clanga"), eastern imperial eagle ("Aquila heliaca"), saker falcon ("Falco cherrug"), houbara bustard ("Chlamydotis undulata"), great bustard ("Otis tarda"), spur-thighed tortoise ("Testudo graeca"), Atlantic cod ("Gadus morhua"), European eel ("Anguilla anguilla") and lumpfish ("Cyclopterus lumpus").
The grey gum regenerates by regrowing from the base and branches after bushfire. Trees live for over a hundred years. The grey-headed flying fox ("Pteropus poliocephalus") eats the flowers, while the leaves form a staple of the diet of the koala ("Phascolarctos cinereus"). Leaves in winter contain less nitrogen than those in summer, which the koalas make up for by eating more in winter months. The brown-headed honeyeater ("Melithreptus brevirostris") and yellow-tufted honeyeater ("Lichenostomus melanops") have been observed eating gum exudate from the stems. 
Fieldwork at several sites around central New South Wales showed that the red wattlebird ("Anthochaera carunculata") and noisy friarbird ("Philemon corniculatus") preferred to forage on the foliage of the grey gum over other trees, with the former appearing to oust the latter if both species were present.
Pallid sturgeon are generally bottom feeders, skimming the sandy reaches of the various rivers and streams in their habitat. Though little is known about the precise eating habits of the species, they are thought to be opportunistic feeders. One study which examined the contents from the stomachs of juvenile pallid sturgeon revealed that their diets were seasonally dependent. Various insects were consumed during some seasons and various fish species during others. These results support the description of the pallid sturgeon's eating habits as opportunistic. Fish is a more important dietary staple for pallid sturgeon than it is for shovelnose sturgeon. In one study comparing dietary tendencies between adult shovelnose sturgeon and immature pallid sturgeon, the pallid sturgeon was found to consume far greater numbers of small fish such as cyprinids (minnows). In another study conducted in the upper Missouri River region, an examination of the stomach contents of hatchery-reared pallid sturgeon showed that 82% of the wet weight was small fish and the balance was mosquito-like insects, mayflies, and caddis flies and small amounts of detritus and plant material.
The American oystercatcher feeds almost exclusively on shellfish and other marine invertebrates. Oysters are a staple of their diet, as their name suggests, but they also eat mussels, clams, limpets, sea urchins, starfish, crabs, and worms. In general, they use their bills to catch shellfish. As they walk across a shellfish bed, they look for a mollusk with a partially opened shell. When they find one, they jab their bill into the shell and sever the muscle that causes the shell to clamp shut. This can be dangerous, however, as they are sometimes drowned when they don't completely severe this muscle and the shell clamps down on their bill. A strong, tightly rooted mollusk can hold the bird in place until the tide comes in. They also feed by carrying loose shellfish out of the water and hammering at the shell or by probing the sand for soft-shell or razor clams.
In the Iberian peninsula, the Eurasian eagle-owl is part of a complex guild of predators that have evolved to survive mostly on European rabbits. Among this guild, golden eagles ("Aquila chrysaetos") were recorded per one study to rely on rabbits for 40% of the diet, the eagle-owl for 49% of the diet, the Spanish imperial eagle ("Aquila adalberti") for 50% of the diet, the Bonelli's eagle ("Aquila fasciata") for 61% of the diet and the Iberian lynx ("Lynx pardinus") for 79% of the diet. Elsewhere, the Spanish imperial eagle and eagle-owl are considered to outflank the golden and even the Bonelli's eagle as the most specialized avian predator of rabbits in the Iberian region. Other predators, such as common buzzard ("Buteo buteo"), northern goshawk ("Accipiter gentilis") black kite ("Milvus migrans") Iberian wildcat ("Felis silvestris tartessia"), red fox, stone marten ("Martes foina") and introduced Egyptian mongoose also prey heavily on rabbits in Spain, but are more generalized and less reliant than the above predators. All these powerful predators do not generally compete directly for food but conflicts may ensue over the rights to territories and nesting sites amongst the birds. Being nocturnal in activity, however, the Eurasian eagle-owl does not tend to compete as directly as do the three eagle species and even these are discreetly segregated by habitat preferences, the goldens preferring open, steep cliffs, the Bonelli's favoring densely vegetated areas mixed with rocky spots and the imperial favoring relatively flat open woodlands. Among these eagles, the golden eagle tends to have the most similar habitat preferences to the Eurasian eagle-owl and across a broad band of overlapping distribution, the two are considered nearly ecological equivalents by day and night. However, good-sized female golden eagles are up to twice as heavy as an average eagle-owl, so seem to have a considerable advantage in size and power. Conversely, to support their large size and large territory needs, the golden eagle cannot survive on small and diverse prey nearly as successfully as the eagle-owl. Among the Iberian peninsula rabbit-eating guild, the species with wider ranges, the eagle-owl and the golden and Bonelli's eagles, have had some degree of success living off of alternate prey following the devastation of the rabbit population due to rabbit haemorrhagic disease. The two rabbit predators endemic to Iberia, the Iberian lynx and Spanish imperial eagle, have been devastated by the reduction and other causes and both are threatened species today.
Common insects that prey on wasps include praying mantises, dragonflies, centipedes, beetles and moths. In fact, large wasps will even prey on smaller wasps. Spiders will also capture wasps in their webs and eat them. Predatory reptiles and amphibians, such as frogs, lizards, toads, and salamanders see the wasp as just another opportunistic meal and do not differentiate them from other insects, despite their feared sting. Birds that regularly consume bugs will also eat wasps. Other creatures that eat wasps, particularly mammals, are more interested in the larvae rather than the adults.
Mammals native to the state include the bat, black bear, bobcat, cougar, coyote, deer, elk, gray wolf, moose, mountain beaver, muskrat, opossum, pocket gopher, raccoon, river otter, skunk, and tree squirrel. Because of the wide range of geography, the State of Washington is home to several different ecoregions which allow for a varied range of bird species. This range includes raptors, shorebirds, woodland birds, grassland birds, ducks, and others. There have also been a large number of species introduced to Washington, dating back to the early 18th century, including horses and burros. The channel catfish, lamprey, and sturgeon are among the 400 known freshwater fishes. Along with the Cascades frog, there are several forms of snakes that define the most prominent reptiles and amphibians. Coastal bays and islands are often inhabited by plentiful amounts of shellfish and whales. There are five species of salmon that ascend the Western Washington area, from streams to spawn.
Lowe speculated in his 1927 paper that, in the absence of mammalian predators on the island, the brown skua would be the Inaccessible Island rail's only predator. A study of the diet of brown skuas on Inaccessible Island confirmed this, but found that although skuas do eat adults of this species, the rail and other landbirds formed only a small part of the diet of that seabird, especially compared to their abundance on the island. They noted that the landbirds alarm-called when brown skuas were seen. After hearing another rail make an alarm call, adult Inaccessible Island rails become alert, while chicks fall silent. Adults are rarely preyed upon, but the mortality of chicks is high and predation by Tristan thrushes is a major cause of death.
This bird feeds at night, eating various invertebrates and small vertebrates. While in mangroves, it commonly feeds on crabs. Otherwise, it will generally feed on molluscs, arthropods, frogs, seeds, berries, palm fruits, and the occasional water snake. Maize, rice, and bananas are also viable food items for the grey-necked wood rail. It is also known to feed on the feces of giant otters at latrines.
Introduced predators are a threat to vulnerable island populations. In addition to the extirpation of the Icelandic race, mink have been responsible for marked declines in the populations of water rails and other ground-nesting birds in the Hebrides, where the mainly fish-eating otter was the only native carnivore. The mink derived from fur farms on Lewis, from whence they spread through Harris, North Uist and South Uist. Mink and ferret eradication programmes have enabled the rail to return to islands including Lewis and Harris, and further projects are ongoing or planned on the Scottish mainland. Locally, habitat may be affected by the drainage of marshes, canalisation of water courses, urban encroachment, and by pollution.
These birds eat crustaceans, aquatic insects, and small fish. They search for food while walking, sometimes probing with their long bills, in shallow water or mud.