This is a list of the bird species recorded in Guam. The avifauna of Guam includes a total of 146 species as of August 2021, according to Bird Checklists of the World.
[1] Of them, eight have been introduced by humans and 32 are rare or accidental. 3 species are endemic, of which one is extinct and two are extinct in the wild though their reintroductions are either in progress or planned. Five species have been extirpated.
Anatidae includes the ducks and most duck-like waterfowl, such as geese and swans. These birds are adapted to an aquatic existence with webbed feet, flattened bills, and feathers that are excellent at shedding water due to an oily coating.
The Megapodiidae are stocky, medium-large chicken-like birds with small heads and large feet. All but the malleefowl occupy jungle habitats and most have brown or black coloring.
Swifts are small birds which spend the majority of their lives flying. These birds have very short legs and never settle voluntarily on the ground, perching instead only on vertical surfaces. Many swifts have long swept-back wings which resemble a crescent or boomerang.
Rallidae is a large family of small to medium-sized birds which includes the rails, crakes, coots, and gallinules. Typically they inhabit dense vegetation in damp environments near lakes, swamps, or rivers. In general they are shy and secretive birds, making them difficult to observe. Most species have strong legs and long toes which are well adapted to soft uneven surfaces. They tend to have short, rounded wings and to be weak fliers. The Guam rail was formerly extinct in the wild but has been reintroduced to Rota and Cocos Island near Guam.[4]
Recurvirostridae is a family of large wading birds which includes the avocets and stilts. The stilts have extremely long legs and long, thin, straight bills.
The family Charadriidae includes the plovers, dotterels, and lapwings. They are small to medium-sized birds with compact bodies, short thick necks, and long, usually pointed, wings. They are found in open country worldwide, mostly in habitats near water.
Scolopacidae is a large diverse family of small to medium-sized shorebirds including the sandpipers, curlews, godwits, shanks, tattlers, woodcocks, snipes, dowitchers, and phalaropes. The majority of these species eat small invertebrates picked out of the mud or soil. Variation in length of legs and bills enables multiple species to feed in the same habitat, particularly on the coast, without direct competition for food.
The pratincoles have short legs, very long pointed wings, and long forked tails. Their most unusual feature for birds classed as waders is that they typically hunt their insect prey on the wing like swallows.
Laridae is a family of medium to large seabirds, the gulls, terns, and skimmers. Gulls are typically gray or white, often with black markings on the head or wings. They have stout, longish bills and webbed feet. Terns are a group of generally medium to large seabirds typically with gray or white plumage, often with black markings on the head. Most terns hunt fish by diving but some pick insects off the surface of fresh water. Terns are generally long-lived birds, with several species known to live in excess of 30 years.
The northern storm-petrels are relatives of the petrels and are the smallest seabirds. They feed on planktonic crustaceans and small fish picked from the surface, typically while hovering. The flight is fluttering and sometimes bat-like.
The procellariids are the main group of medium-sized "true petrels", characterized by united nostrils with medium septum and a long outer functional primary.
Frigatebirds are large seabirds usually found over tropical oceans. They are large, black and white, or completely black, with long wings and deeply forked tails. The males have colored inflatable throat pouches. They do not swim or walk and cannot take off from a flat surface. Having the largest wingspan-to-body-weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week.
The family Ardeidae contains the bitterns, herons, and egrets. Herons and egrets are medium to large wading birds with long necks and legs. Bitterns tend to be shorter necked and more wary. Members of Ardeidae fly with their necks retracted, unlike other long-necked birds such as storks, ibises, and spoonbills.
The family Pandionidae contains only one species, the osprey. The osprey is a medium-large raptor which is a specialist fish-eater with a worldwide distribution.
Accipitridae is a family of birds of prey which includes hawks, eagles, kites, harriers, and Old World vultures. These birds have powerful hooked beaks for tearing flesh from their prey, strong legs, powerful talons, and keen eyesight.
The typical owls are small to large solitary nocturnal birds of prey. They have large forward-facing eyes and ears, a hawk-like beak and a conspicuous circle of feathers around each eye called a facial disk.
Kingfishers are medium-sized birds with large heads, long pointed bills, short legs and stubby tails. An attempt to reintroduce the Guam kingfisher is in the planning stage as of early 2020.[5]
Rollers resemble crows in size and build, but are more closely related to the kingfishers and bee-eaters. They share the colorful appearance of those groups with blues and browns predominating.
The honeyeaters are a large and diverse family of small to medium-sized birds most common in Australia and New Guinea. They are nectar feeders and closely resemble other nectar-feeding passerines.
The drongos are mostly black or dark gray in color, sometimes with metallic tints. They have long forked tails, and some Asian species have elaborate tail decorations. They have short legs and sit very upright when perched, like a shrike. They flycatch or take prey from the ground.
The family Acrocephalidae is a group of small insectivorous passerine birds. Most are of generally undistinguished appearance, but many have distinctive songs.
The family Hirundinidae is adapted to aerial feeding. They have a slender streamlined body, long pointed wings, and a short bill with a wide gape. The feet are adapted to perching rather than walking, and the front toes are partially joined at the base.
The white-eyes are small and mostly undistinguished, their plumage above being generally some dull color like greenish-olive, but some species have a white or bright yellow throat, breast, or lower parts, and several have buff flanks. As their name suggests, many species have a white ring around each eye.
Starlings are small to medium-sized passerine birds. Their flight is strong and direct and they are very gregarious. Their preferred habitat is fairly open country. They eat insects and fruit. Plumage is typically dark with a metallic sheen.
The Old World flycatchers form a large family of small passerine birds. These are mainly small arboreal insectivores, many of which, as the name implies, take their prey on the wing.
The members of this family are small passerine birds native to the Old World tropics. They are gregarious and often colonial seed eaters with short thick but pointed bills. They are all similar in structure and habits, but have wide variation in plumage colors and patterns.
Old World sparrows are small passerine birds. In general, sparrows tend to be small, plump, brown, or gray birds with short tails and short powerful beaks. Sparrows are seed eaters, but they also consume small insects.
Motacillidae is a family of small passerine birds with medium to long tails. They include the wagtails, longclaws, and pipits. They are slender ground-feeding insectivores of open country.
^Lepage, Denis (August 26, 2019). "Checklist of Birds of Guam". Avibase bird checklists of the world. Retrieved April 8, 2020.
^Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements Checklist of Birds of the World: v2022. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/ Retrieved October 25, 2022.
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