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Bird
Birds: endothermic, feathered vertebrates and living theropod dinosaurs, with powered flight, air-filled bones, and unidirectional lung ventilation; over 11,000 species, 61% declining, 1 in 8 threatened with extinction.
Bird anatomy
Bird anatomy: structure of birds (Aves), feathered theropod dinosaurs. Rigid lungs ventilated by 7-9 air sacs with unidirectional parabronchial airflow, keeled sternum, furcula, pygostyle, crop, and gizzard.
Bird flight
Bird flight: powered flight by birds using feathered wings, evolved from small theropod dinosaurs with Archaeopteryx about 150 million years ago; lift, thrust, pectoralis-driven flapping, repeated origins, and at least 150 losses of flight.
Bird intelligence
Bird intelligence: complex cognition in birds, chiefly corvids (crows, ravens, jays) and parrots, showing ape-like tool use, planning, and vocal learning despite small, cortex-free brains with primate-like neuron counts.
Bird migration
Bird migration: seasonal movement of birds between breeding and nonbreeding grounds. Also called partial migration when only part of a population migrates; birds navigate with sun, star, and magnetic compasses; 45% of migratory bird species are declining.
Bird nest
Bird nest: the structure or site where birds lay eggs and raise young. Ten recognized types from scrape to mound; climate explains more architectural variation than predation; nestboxes can become ecological traps under heatwaves.
Bird of prey
Bird of prey (raptor, from Latin rapere, to seize): carnivorous birds with hooked beaks, talons, and keen vision, including hawks, eagles, falcons, owls, and vultures; over 300 diurnal species, 18% threatened globally.
Bird sanctuary
Bird sanctuary: an area of land or water set aside by governments, communities, or private entities to protect birds, closed to hunting and disturbance. From Last Mountain Lake (1887) and Pelican Island (1903) to EU SPAs and community ecotourism sites.
Bird species
Bird species: distinct bird populations treated as evolutionary lineages, roughly 10,000 living species split into Palaeognathae and Neognathae, with 11% threatened and three in five declining.
Bird vision
Bird vision: tetrachromatic avian visual system with four single cone types, double cones, colored oil droplet filters, and secondarily re-evolved ultraviolet sensitivity via Ser90Cys; raptor acuity 3–5x human.
Bird vocalization
Bird vocalization: sounds birds make via the syrinx, a dual-source vocal organ at the tracheobronchial junction using the MEAD mechanism. Covers calls versus song, vocal learning in songbirds, parrots, and hummingbirds, and bioacoustic monitoring.
Bird-of-paradise
Birds-of-paradise (Paradisaeidae), 39–45 species of New Guinean passerines with extreme male plumage and courtship displays driven by sexual selection; 37 of 45 species biofluorescent; riflebirds and manucodes also in Australia.
BirdLife International
BirdLife International, founded 20 June 1922 in London as the International Committee for Bird Protection, is a global partnership of over 120 national bird conservation NGOs. It is the IUCN Red List Authority for birds and creator of the IBA and KBA site networks.
Birdwatching
Birdwatching (birding): recreational observation and identification of wild birds using binoculars, field guides, and apps. Key facts: eBird has 2+ billion records since 2002; Christmas Bird Count dates to 1901; Peterson's 1934 field guide; Merlin Sound ID (2021); RSPB reports 1,088% Gen Z surge.
Black drongo
Black drongo (Dicrurus macrocercus), a 30-31 cm all-black Asian passerine with a deeply forked tail, common in open farmland; insectivorous, aggressive, a vocal mimic, IUCN Least Concern with seven subspecies.
Black eagle
Black eagle (Ictinaetus malaiensis), sole species of genus Ictinaetus, a dark forest raptor of South and Southeast Asia; long fingered wings, yellow cere and feet, nest-raiding diet; IUCN Least Concern but decreasing.
Black kite
Black kite (Milvus migrans), a widespread dark raptor of Eurasia, Africa, and Australia; Least Concern with 4–5.7 million mature individuals; split from the yellow-billed kite; subspecies include migrans, lineatus, govinda.
Black swan
Black swan (Cygnus atratus), kakīānau: a large black Australian waterbird with white flight feathers and a red bill, native to Australia and Tasmania, introduced to New Zealand, Europe, and North America; IUCN Least Concern, population c.100,000–1,000,000.
Black vulture
The black vulture (Coragyps atratus), also called the American black vulture, is a sooty-black New World vulture that scavenges carrion across the Americas, from the southeastern United States to central Chile and Uruguay.
Black-billed magpie
Black-billed magpie (Pica hudsonia), also called Urraca de Hudson, a long-tailed black-and-white corvid of western North America; omnivorous ground forager, tick-picker on large mammals, IUCN Least Concern with about 6 million birds.
Black-capped chickadee
Black-capped chickadee (Poecile atricapillus), Mésange à tête noire, a small North American Paridae songbird with black cap and bib, caching thousands of seeds, and a northward-moving hybrid zone with the Carolina chickadee.
Black-crowned night heron
Black-crowned night heron (Nycticorax nycticorax), also called night heron or ʻaukuʻu in Hawaii, is a stocky nocturnal heron of Ardeidae, the world's most widespread heron, IUCN Least Concern with 440,000–1,990,000 mature individuals but declining regionally.
Black-faced cuckooshrike
Black-faced cuckooshrike (Coracina novaehollandiae), also called Shufflewing or Blue Jay, a 32–34 cm blue-grey Australian and southern New Guinea songbird with a black face and throat, wing-shuffling habit, IUCN Least Concern.
Black-legged kittiwake
Black-legged kittiwake (Rissa tridactyla), a small cliff-nesting gull of northern oceans with black wingtips and legs; IUCN Vulnerable, with severe North Atlantic declines from food shortage, fisheries, climate change, and 2023 avian flu.
Blackbird
Blackbird (Turdus merula), also Eurasian or Common Blackbird, Amsel, merle: a common Eurasian thrush; males black with yellow bill, females brown; 5.1 million UK pairs, declining in London due to Usutu virus.
Blakiston's fish owl
Blakiston's fish owl (Bubo blakistoni) is an Endangered owl of northeast Asia and the heaviest living owl, feeding on fish along rivers in Russia and Japan.
Bleda
Bleda (bristlebills) is a genus of African lowland-forest bulbuls, family Pycnonotidae, erected by Bonaparte in 1857; five species including B. ugandae, split from B. notatus in 2024, with Miocene West African origins.
Blue jay
Blue jay (Cyanocitta cristata), a crested corvid of eastern North America from southern Canada to Texas and Florida; omnivorous acorn cacher, partial migrant, IUCN Least Concern, global population about 17 million.
Blue-and-yellow macaw
Blue-and-yellow macaw (Ara ararauna), also blue-and-gold macaw: large Neotropical parrot, 81-86 cm, IUCN Least Concern, CITES Appendix II, ranging Panama to Paraguay, reintroduced to Trinidad.
Blue-footed booby
Blue-footed booby (Sula nebouxii), Piquero Camanay, a tropical eastern Pacific seabird whose bright blue feet signal quality in mutual courtship displays; socially monogamous with frequent extrapair copulations, siblicidal broods, and breeding strongly suppressed by El Niño warming.