Bird - Wikipedia Birds are a group of warm-blooded vertebrates constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton
Guide to North American Birds | Audubon Explore more than 800 North American bird species, learn about their lives and habitats, and how climate change is impacting their ability to survive
Bird | Description, Species, Feathers, Facts | Britannica Bird, any of the more than 10,400 living species unique in having feathers, the major characteristic that distinguishes them from other animals They are warm-blooded vertebrates more related to reptiles than mammals
Bird Pictures Facts - National Geographic Birds are vertebrate animals adapted for flight Many can also run, jump, swim, and dive Some, like penguins, have lost the ability to fly but retained their wings Birds are found worldwide
eBird - Discover a new world of birding. . . eBird transforms your bird sightings into science and conservation Plan trips, find birds, track your lists, explore range maps and bird migration—all free
Birds of the World - Cornell Lab of Ornithology Birds of the World is a powerful resource that brings deep, scholarly content from four celebrated works of ornithology into a single platform where biologists and birders can find comprehensive life history information on birds Every bird has a story Discover them all with Birds of the World
Whats That Bird? | Audubon Have you ever seen a large, black bird fly by and wondered: Is that a crow or a raven? Do you have trouble telling the difference between a swallow and a swift?