Birds are among the most extensively studied of all animal groups. Hundreds of academic journals and thousands of scientists are devoted to bird research, while amateur enthusiasts (called birdwatchers or, more commonly, birders) probably number in the millions. Birds are categorised as a biological class, Aves. The earliest known species of this class is Archaeopteryx lithographica, from the Late Jurassic period. According to the most recent consensus, Aves and a sister group, the order Crocodilia, together form a group of unnamed rank, the Archosauria. Phylogenetically, Aves is usually defined as all descendants of the most recent common ancestor of modern birds (or of a specific modern bird species like Passer domesticus), and Archaeopteryx. Modern phylogenies place birds in the dinosaur clade Theropoda. Modern birds are divided into two superorders, the Paleognathae (mostly flightless birds like ostriches), and the wildly diverse Neognathae, containing all other birds.When a rooster finds food he may call the other chickens to eat it first. ... A broody hen guarding her eggs Sometimes a hen will stop laying and instead will focus on the incubation of eggs, a state that is ... During this time, the newly-hatched chicks live off the egg yolk they absorb just before hatching. ... Some breeds, such as the Cochin, Cornish and Silkie, regularly go broody and make excellent mothers.
|Title||:||The Birds World|
|Publisher||:||Nicolae Sfetcu - 2014-11-27|