accipitriformes aetosaur albian animal anseriformes antarctica apodiformes archaeopteryx archosaur archosauromorpha asiahesperornis avemetatarsalia avialae avian avian incubation aviculture baptornis biological classification bird bird anatomy bird collections bird conservation bird evolution bird feeding bird flight bird hybrid bird intelligence bird migration bird nest bird ringing bird vision bird vocalization birdwatching brood parasite canadaga caprimulgiformes charadriiformes choristodera ciconiiformes clade columbiformes confuciusornis coniornis convergent evolution coraciiformes cretaceous crocodilia crocodylomorpha crurotarsi cuculiformes digital object identifier dinosaur dinosauromorpha early cretaceous enaliornis enantiornithes erythrosuchidae euparkeria eurasia falconiformes feather fish flamingo fossil galliformes genus grebe gruiformes hell creek formation hesperornis hesperornithidae ichthyornis ichthyosaur judinornis judith river group lance formation late cretaceous late quaternary prehistoric birds list of birds list of extinct birds list of fossil birds lists of birds by region loon maastrichtian mesozoic modern birds mousebird neogaeornis neognathae odontornithes ornithischia ornithodira ornithology ornithosuchidae ornithurae osteon othniel charles marsh owl paleognathae parahesperornis parrot pasquiaornis passerine pelecaniformes penguin phytosaur piciformes plesiosaur plumage potamornis procellariiformes prolacertiformes proterochampsidae proterosuchidae pterosaur pygostyle ratite rauisuchia reptile rhynchosaur richard bowdler sharpe sandgrouse saurischia sauropsida scleromochlus seabird seriema sibley-ahlquist taxonomy synapomorphy taxon tinamou trilophosaur trogon tropicbird uropygial gland