Gleaning is a term for a feeding strategy by birds in which they catch invertebrate prey, mainly arthropod

Arthropod

An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

s, by plucking them from foliage or the ground, from crevices such as rock faces and under the eaves of houses, or even, as in the case of ticks and lice, from living animals. This behavior is contrasted with hawking

Hawking (birds)

Hawking is a feeding strategy in birds involving catching flying insects in the air. The term usually refers to a technique of sallying out from a perch to snatch an insect and then returning to the same or a different perch...

 insects from the air or chasing after moving insects such as ants. Gleaning, in birds, does not refer to foraging for seeds or fruit.

Gleaning is a common feeding strategy for some groups of birds, including nuthatch

Nuthatch

The nuthatches are a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs...

es, tits (including chickadees), wrens, woodcreepers

Ovenbird (family)

Ovenbirds or furnariids are a large family of small suboscine passerine birds found in Mexico, and Central and South America. They form the family Furnariidae...

, treecreeper

Treecreeper

The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains ten species in two genera, Certhia and Salpornis...

s, Old World flycatcher

Old World flycatcher

The Old World flycatcher family Muscicapidae is a large family of small passerine birds mostly restricted to the Old World. These are mainly small arboreal insectivores, many of which, as the name implies, take their prey on the wing.-Characteristics:...

s, Tyrant flycatcher

Tyrant flycatcher

The tyrant flycatchers are a family of passerine birds which occur throughout North and South America. They are considered the largest family of birds on Earth, with more than 400 species. They are the most diverse avian family in every country in the Americas, except for the United States and...

s, babbler

Old World babbler

The Old World babblers or timaliids are a large family of mostly Old World passerine birds. They are rather diverse in size and coloration, but are characterised by soft fluffy plumage. These are birds of tropical areas, with the greatest variety in Southeast Asia and the Indian Subcontinent...

s, Old World warbler

Old World warbler

The "Old World Warblers" is the name used to describe a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into...

s, New World warbler

New World warbler

The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....

s, and some hummingbird

Hummingbird

Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings...

s and cuckoo

Cuckoo

The cuckoos are a family, Cuculidae, of near passerine birds. The order Cuculiformes, in addition to the cuckoos, also includes the turacos . Some zoologists and taxonomists have also included the unique Hoatzin in the Cuculiformes, but its taxonomy remains in dispute...

s. Many birds make use of multiple feeding strategies, depending on the availability of different sources of food and opportunities of the moment.

Techniques and adaptations

Foliage gleaning, the strategy of gleaning over the leaves and branches of trees and shrubs, can involve a variety of styles and maneuvers. Some birds, such as the Common Chiffchaff  of Eurasia and the Wilson's Warbler

Wilson's Warbler

The Wilson's Warbler, Wilsonia pusilla, is a small New World warbler. It is primarily greenish above and yellow below, with rounded wings and a long, slim tail. The male has a black crown patch which is greatly reduced or missing entirely in the female...

 of North America, feed actively and appear energetic. Some will even hover in the air near a twig while gleaning from it; this behavior is called "hover-gleaning". Other birds are more methodical in their approach to gleaning, even seeming lethargic as they perch upon and deliberately pick over foliage. This behavior is characteristic of the Bay-breasted Warbler

Bay-breasted Warbler

The Bay-breasted Warbler, Dendroica castanea , is a New World warbler. They breed in northern North America, specifically in Canada, into the Great Lakes region, and into northern New England....

 and many vireo

Vireo

The vireos are a group of small to medium-sized passerine birds restricted to the New World. They are typically dull-plumaged and greenish in color, the smaller species resembling wood warblers apart from their heavier bills...

s. Another tactic is to hang upside-down from the tips of branches to glean the undersides of leaves. Tits such as the familiar Black-capped Chickadee

Black-capped Chickadee

The Black-capped Chickadee is a small, North American songbird, a passerine bird in the tit family Paridae. It is the state bird of both Maine and Massachusetts in the United States, and the provincial bird of New Brunswick in Canada...

 are often observed feeding in this manner. Some birds, like the Ruby-crowned Kinglet and Red-eyed Vireo

Red-eyed Vireo

The Red-eyed Vireo, Vireo olivaceus, is a small American songbird, 13–14 cm in length. It is somewhat warbler-like but not closely related to the New World warblers...

 of North America use a combination of these tactics.

Gleaning birds are typically small with compact bodies and have small, sharply pointed bills

Beak

The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...

. These features are even seen in gleaning birds that are not closely related. For example, in flycatchers of the family Tyrannidae, in which some member species are more adapted for hawking insects on the wing and others for gleaning, the gleaners have bills that resemble those of tits and warblers, unlike their larger-billed relatives. Also, some members of the woodpecker

Picidae

The woodpeckers, piculets and wrynecks are a family, Picidae, of near-passerine birds. Members of this family are found worldwide, except for Australia and New Zealand, Madagascar, and the extreme polar regions...

 family, particularly piculet

Piculet

The piculets are a distinctive subfamily of small woodpeckers which occur mainly in tropical South America, with just three Asian and one African species....

s such as the Rufous Piculet

Rufous Piculet

The Rufous Piculet is a species of bird in the Picidae family.It is found in Brunei, Indonesia, Malaysia, Myanmar, and Thailand....

 of Southeast Asia, are similarly adapted for gleaning, with small, compact bodies and sharp bills, rather than the long, supportive tails and wedge-shaped bills more typical of woodpeckers. Birds such as the aforementioned piculet are specialized for gleaning the bark of trees, as are nuthatches, woodcreepers, and treecreepers. Most bark-gleaners work their way up tree trunks or along branches, though nuthatches are well known as the birds that can go the opposite direction, facing down and working their way down the trunk, as well. This requires strong legs and feet on the part of the nuthatch and piculet, while birds that face upwards tend to have stiff tail feathers to prop them up.

Birds often specialize in a particular niche, such as a particular stratum of forest or type of vegetation. In South and Southeast Asia, for example, the Mountain Tailorbird

Mountain Tailorbird

The Mountain Tailorbird is a songbird species formerly placed in the "Old World warbler" assemblage with the other tailorbirds, but it actually seems to be one of the "pseudo-tailorbirds" which should be considered a genus Phyllergates in the family Cettiidae.It is found in Bangladesh, Bhutan,...

 is often found gleaning in thickets and stands of bamboo

Bamboo

Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....

, Abbott's Babbler

Abbott's Babbler

Abbott's Babbler is a species of bird in the Timaliidae family. It is widely distributed along the Himalayas in South Asia and extending into the forests of Southeast Asia...

 gleans lower-storey foliage in lowland forest, the Rufous-chested Flycatcher

Rufous-chested Flycatcher

The Rufous-chested Flycatcher is a species of bird in the Muscicapidae family. It is found in Brunei, Indonesia, Malaysia, and Thailand....

 and Brown Fulvetta

Brown Fulvetta

The Brown Fulvetta is a species of bird in the Timaliidae family.It is found in Brunei, Indonesia, Malaysia, and Thailand.Its natural habitat is subtropical or tropical moist lowland forests.It is threatened by habitat loss....

 are birds of the mid-storey forest, the Yellow-breasted Warbler

Yellow-breasted Warbler

The Yellow-breasted Warbler is a species of Old World warbler in the Phylloscopidae family.It is found in Indonesia, Malaysia, and the Philippines....

 gleans in the mid- to upper-storey, and the Greater Green Leafbird

Greater Green Leafbird

The Greater Green Leafbird is a species of bird in the Chloropseidae family. It is distinguished from the Lesser Green Leafbird by its powerful beak, yellow throat and eye ring of the female; and lack of a yellow border along the black throat patch found in the male c...

 specializes in the upper-storey forest. The Javan White-eye

Javan White-eye

The Javan White-eye is a species of bird in the Zosteropidae family.It is found in Indonesia and Malaysia.Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical moist shrubland.It is threatened by habitat...

 is a bird of coastal scrub and mangroves, while the related Black-capped White-eye

Black-capped White-eye

The Black-capped White-eye is a small passerine from the family Zosteropidae.-Description:It can reach a length between nine and eleven centimetres and looks slightly similar to the Oriental White-eye. The forehead and the crown are blackish and its upperparts and underparts are darker than at the...

 is restricted to montane forest

Cloud forest

A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...

.
Further specialization within a habitat is associated with behaviors and morphological adaptations (physical traits of size and shape). Tiny birds are lightweight enough to hang onto the ends of twigs and pluck small prey; the Goldcrest

Goldcrest

The Goldcrest, Regulus regulus, is a very small passerine bird in the kinglet family. Its colourful golden crest feathers gives rise to its English and scientific names, and possibly to it being called the "king of the birds" in European folklore. Several subspecies are recognised across the very...

 of Europe and its counterpart the Golden-crowned Kinglet

Golden-crowned Kinglet

The Golden-crowned Kinglet, Regulus satrapa, is a very small songbird.Adults are olive-gray on the upperparts with white underparts, with thin bills and short tails. They have white wing bars, a black stripe through the eyes and a yellow crown surrounded by black...

 of North America exhibit this feeding style. The related Common Firecrest is very similar in size and shape, but slightly bulkier, and has less of a tendency to glean along twigs and more of a habit of flying from perch to perch. Having a very small bill seems to be good for taking tiny prey from the surfaces of leaves, and small-billed birds such as the Blue Tit

Blue Tit

The Blue Tit is a 10.5 to 12 cm long passerine bird in the tit family Paridae. It is a widespread and common resident breeder throughout temperate and subarctic Europe and western Asia in deciduous or mixed woodlands...

 forage in broad-leafed woodlands. The Long-billed Gnatwren

Long-billed Gnatwren

The Long-billed Gnatwren is a very small bird in the gnatcatcher family. It is the only member of the genus Ramphocaenus ....

 and Speckled Spinetail

Speckled Spinetail

The Speckled Spinetail is a species of bird in the Furnariidae family.It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru, Suriname, and Venezuela....

 of Central and South America, and the Ashy Tailorbird

Ashy Tailorbird

The Ashy Tailorbird is a species of Old World warbler in the Sylviidae family.It is found in Brunei, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, and Thailand, Vietnam....

 and Striped Tit-babbler

Striped Tit-babbler

The Pin-striped Tit-babbler also known as the Yellow Breasted Babbler is a species of Old World babbler found in South and Southeast Asia.-Description:...

 of South Asia, show a preference for gleaning in tangles of vines. The Ash-browed Spinetail

Ash-browed Spinetail

The Ash-browed Spinetail is a species of bird in the Furnariidae family.It is found in Bolivia, Colombia, Ecuador, and Peru.Its natural habitat is subtropical or tropical moist montanes.-References:...

 of South America specializes in gleaning among epiphyte

Epiphyte

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

s on moss-covered tree branches. Many hummingbird

Hummingbird

Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings...

s take small insects from flowers while probing for nectar, and some species glean actively among bark and leaves. The Puerto Rican Emerald

Puerto Rican Emerald

The Puerto Rican Emerald , or Zumbadorcito de Puerto Rico in Spanish, is an endemic hummingbird found only in the archipelago of Puerto Rico....

 is one such hummingbird. Found only on the island of Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

, the female subsists on insects and spiders, while the male has a typical hummingbird diet of nectar. Hummingbirds and other gleaners are also sometimes attracted to the sap wells created by sapsucker

Sapsucker

The Sapsuckers form the genus Sphyrapicus within the woodpecker family Picidae. All are found in North America.As their name implies, sapsuckers feed primarily on the sap of trees, moving among different tree and shrub species on a seasonal basis...

s. Sapsuckers, which are in the woodpecker family, drill small holes in living tree branches to get the sap flowing. The sap and the insects it attracts are then consumed, and Rufous Hummingbird

Rufous Hummingbird

The Rufous Hummingbird is a small hummingbird, about 8 cm long with a long, straight and very slender bill. The female is slightly larger than the male.-Description:...

s have been observed to follow the movements of sapsuckers and take advantage of this food source. Clusters of dead leaves also often harbor invertebrate prey, and the Bewick's Wren

Bewick's Wren

The Bewick's Wren is a wren native to North America. At about 14 cm long, it is grey-brown above, white below, with a long white eyebrow. While similar in appearance to the Carolina Wren, it has a long tail that is tipped in white. The song is loud and melodious, much like the song of other...

 and Worm-eating Warbler

Worm-eating Warbler

The Worm-eating Warbler is a small New World warbler. It is the only species classified in the genus Helmitheros....

 of North America have long bills well-suited for probing them, as do certain Asian babbler

Old World babbler

The Old World babblers or timaliids are a large family of mostly Old World passerine birds. They are rather diverse in size and coloration, but are characterised by soft fluffy plumage. These are birds of tropical areas, with the greatest variety in Southeast Asia and the Indian Subcontinent...

s, such as the Rusty-cheeked Scimitar-babbler

Rusty-cheeked Scimitar-babbler

The Rusty-cheeked Scimitar-babbler is a species of bird in the Timaliidae family.It is found in Bangladesh, Bhutan, China, India, Myanmar, Nepal, Pakistan, Taiwan, and Thailand. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane...

. In Central and South America, foliage-gleaners such as the Red-faced Spinetail

Red-faced Spinetail

The Red-faced Spinetail is a species of bird in the Furnariidae family.It is found in Colombia, Costa Rica, Ecuador, and Panama.Its natural habitat is subtropical or tropical moist montanes....

 and Buff-throated Foliage-gleaner

Buff-throated Foliage-gleaner

The Buff-throated Foliage-gleaner is a species of bird in the Furnariidae family.It is found in Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, and Venezuela...

 are also examples of birds that glean clusters of dead leaves.

Crevice-gleaning is a niche particular to dry and rocky habitats. Adaptations for crevice-gleaning are similar to that of bark-gleaning. Just as the Bewick's Wren, as mentioned in the preceding paragraph, has a long bill suited for poking around in the small places of woods and gardens, another North American wren, the Canyon Wren

Canyon Wren

The Canyon Wren is a small North American wren, and is about 14.5 cm long. It ranges from far southern British Columbia and Montana south through much of Mexico to western Chiapas and east to Oklahoma and Texas...

, has an even longer bill, which allows it to probe crevices in rocky cliffs. It also has skeletal adaptations to aid it in reaching deep into small spaces. These same traits are useful for gleaning the sides of buildings, as well. Another kind of rocky habitat is found along mountain streams, where birds such as the Louisiana Waterthrush

Louisiana Waterthrush

The Louisiana Waterthrush is a New World warbler. It breeds in eastern North America from southernmost Canada and south through the eastern USA, excluding Florida and the coast....

 of North America and the forktail

Forktail

The forktails are small insectivorous birds in the genus Enicurus. They were formerly in the thrush family Turdidae, but are more often now treated as part of the Old World flycatcher family Muscicapidae. Their name derives from their long forked tail....

s of Asia pick over stream-side rocks and exposed roots for aquatic insects and other moisture-loving prey.

Other foraging techniques

Foraging for invertebrate prey on the ground often involves gleaning the leaf litter

Plant litter

Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...

 of the forest floor, sometimes flicking, flipping, or scratching through dead leaves. Birds can use their bills to flick or toss dead leaves from the ground to reveal prey residing beneath. The leaftosser

Sclerurus

Sclerurus is a bird genus in the ovenbird family, Furnariidae. Members of this genus are commonly known as leaftossers or leafscrapers, and are found in Mexico, Central America and South America. They are close relatives of the miners , which are essentially an open-country version of the...

s of Central and South America and the pitta

Pitta

Pitta may stand for:*Pittas, a family of tropical birds*Pitta bread *Pitta , an island in the Dodecanese archipelago, in the Aegean Sea...

s and laughingthrush

Laughingthrush

The Laughingthrushes are the genus Garrulax of the large Old World babbler family of passerine birds. They occur in tropical Asia, with the greatest number of species occurring in the Himalaya and southern China....

es of Asia do this. An example of a bird that employs flipping is the Ovenbird

Ovenbird

The Ovenbird is a small songbird of the New World warbler family . This migratory bird breeds in eastern North America and moves south in winter.-Taxonomy:...

, a species of North American wood-warbler. It deliberately turns over leaves on the ground to search for spiders, worms, and such underneath. In other parts of the world, similar leaf-flipping behavior has been observed in unrelated birds, such as the Jungle Babbler

Jungle Babbler

The Jungle Babbler is an Old World babbler found in the Indian Subcontinent. They are gregarious birds that forage in small groups of six to ten birds, a habit that has given them the popular name of Seven Sisters or Saath bhai in Hindi with cognates in other regional languages which means "seven...

 of India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. Some birds, such as hummingbird

Hummingbird

Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings...

s, will use their wings to create a blast of air to roll leaves over. Other birds rake a foot through the leaf litter, like a chicken, for the same purpose. This has been observed in buttonquail

Buttonquail

Buttonquail or hemipodes are members of a small family of birds, Turnicidae, which resemble, but are unrelated to, the quails of Phasianidae. They inhabit warm grasslands in Asia, Africa, Europe, and Australia...

s. Some American sparrow

American sparrow

American sparrows are a group of mainly New World passerine birds, forming part of the family Emberizidae. American sparrows are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns....

s, such as the Green-tailed Towhee

Green-tailed Towhee

The Green-tailed Towhee, Pipilo chlorurus, is the smallest towhee, but is still one of the larger members of the "American sparrow" family Emberizidae....

, perform a double-scratch by raking both legs simultaneously through the leaf-litter. They then catch prey items dislodged by the disturbance. Ground-foraging birds can be very hard for humans to observe, as they often occupy densely-vegetated habitat, as in the case of the Bornean Wren-babbler

Bornean Wren-babbler

The Bornean Wren-babbler is a species of bird in the Timaliidae family. It is found in Brunei, Indonesia, and Malaysia....

, which specializes in gleaning leaf litter in gullies in the forest of Southeast Asia.

The todies

Tody

The todies are a family, Todidae, of Caribbean birds in the order Coraciiformes, which also includes the kingfishers, bee-eaters and rollers. The family has one genus, Todus...

 of the Caribbean

Caribbean

The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 employ a feeding technique that is somewhere between gleaning and hawking. These small birds choose a perch within their lush forest and plantation habitats in the Greater Antilles

Greater Antilles

The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...

, from which they scan the undersides of leaves above them. Upon spotting an insect or spider, they fly up in an arcing sally, pluck their prey item without stopping, and complete the arcing movement to land on a new perch.
An unusual feeding strategy is that of the oxpeckers of Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

. They perch on living animals and glean parasites from the animals' hides. On furry animals, such as buffalo

African Buffalo

The African buffalo, affalo, nyati, Mbogo or Cape buffalo is a large African bovine. It is not closely related to the slightly larger wild Asian water buffalo, but its ancestry remains unclear...

, giraffe

Giraffe

The giraffe is an African even-toed ungulate mammal, the tallest of all extant land-living animal species, and the largest ruminant...

, and donkey

Donkey

The donkey or ass, Equus africanus asinus, is a domesticated member of the Equidae or horse family. The wild ancestor of the donkey is the African Wild Ass, E...

, these birds run their bills through the fur of the animal, using a scissors-like motion to extract ticks and lice from near the skin. When they pull the insect out to the end of the fur, they catch it and eat it. (On animals with bare hides, such as rhinoceros

Rhinoceros

Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....

 and hippopotamus

Hippopotamus

The hippopotamus , or hippo, from the ancient Greek for "river horse" , is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest...

, oxpeckers pick at any open wounds the animals happen to have, consuming blood and puss, and possibly keeping the wounds free of maggots.) Historically, rhinoceros and other large wild mammals have been among the favored hosts, but as the populations of large mammals in the African savanna have changed in modern times, the population and range of both Red-billed

Red-billed Oxpecker

The Red-billed Oxpecker, Buphagus erythrorhynchus, is a passerine bird in the starling and myna family Sturndidae; some ornithologists regard the oxpeckers to be in a family by themselves, the Buphagidae. It is native to the savannah of sub-Saharan Africa, from the Central African Republic east to...

 and Yellow-billed Oxpecker

Yellow-billed Oxpecker

The Yellow-billed Oxpecker, Buphagus africanus, is a passerine bird in the starling and myna family Sturnidae; some ornithologists regard the Oxpeckers to be a separate family, the Buphagidae . It is native to the savannah of sub-Saharan Africa from Senegal east to Sudan...

 have also changed, and now the birds will use donkeys and domestic cattle

Cattle

Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

 as hosts.

There are other tactics. Dipper

Dipper

Dippers are members of the genus Cinclus in the bird family Cinclidae, named for their bobbing or dipping movements. They are unique among passerines for their ability to dive and swim underwater.-Description:...

s forage underwater in fast-moving streams. Common Grackle

Common Grackle

The Common Grackle, Quiscalus quiscula, is a large icterid.-Description:The long adult has a long dark bill, pale yellowish eyes and a long tail; its feathers appear black with purple, green or blue iridescence on the head, and primarily bronze shine in the body plumage...

s have been observed to follow farmers’ plows to glean the grubs exposed in the fresh soil. Similarly, on the island of Borneo, the Bornean Ground-cuckoo

Bornean Ground-cuckoo

The Bornean Ground Cuckoo is a large terrestrial species of cuckoo in the Cuculidae family. It is, as suggested by its common name, endemic to the island of Borneo, being found in the sections belonging to Brunei, Malaysia and Indonesia. It is restricted to humid forest. It is threatened by...

 will follow wild pigs

Bearded Pig

The bearded pig , also known as the Bornean bearded pig, is a species of pig. It can be recognized by its prominent beard. It also sometimes has tassels on its tail. It is found in Southeast Asia—Sumatra, Borneo, the Malay Peninsula, and various smaller islands—where it inhabits rainforests and...

 and sun bear

Sun Bear

The sun bear , sometimes known as the honey bear, is a bear found primarily in the tropical rainforests of Southeast Asia; North-East India, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Southern China, Peninsular Malaysia, and the islands of Sumatra and Borneo.-Description:The sun bear...

s as they turn up soil while foraging in the forest. Brewer's blackbird

Brewer's Blackbird

The Brewer's Blackbird is a medium-sized New World blackbird, named after the ornithologist Thomas Mayo Brewer....

s are often seen in parking lots, where they pick off dead insects from car grilles. Some hummingbirds are known to take prey items from spiderwebs.

Behavioral implications

Gleaning, like other methods of foraging, is a highly visual activity, and as such has some implications for birds. First, to see requires light, and thus time allotted to gleaning is limited to daytime. Second, while a bird focuses on examining an area for prey items, it must necessarily divert its attention from scanning its surroundings for predators. Birds that glean in tree branches will often join together in a flock, and often with other gleaners in a mixed-species foraging flock. It has been shown that individual birds feeding in flocks are able to spend more time looking for food and less time looking for predators. On the other hand, it is not a universal trait of gleaning birds to join with other species or even to be gregarious with their own kind. The leafbird

Leafbird

The leafbirds are a family of small passerine bird species found in India, Sri Lanka and Southeast Asia. They are one of only three bird families that are entirely endemic to the Indomalayan ecozone. They were formerly grouped with the ioras and fairy-bluebirds in the family Irenidae...

s of Asia are foliage-gleaners, but are often found singly or in pairs.