Birds in the Spring Birds in the Spring Birds in the Spring is a "Silly Symphonies" animated Disney short film. It was released in 1933. Various birds are seen building nests and caring for eggs. One pair anxiously awaits the hatching of three eggs, then joyfully summon all the other birds to see their new, noisy hatchlings. Time jumps forward to when the hatchlings are fully fledged, learning to sing and fly. One becomes lost and explores the ground, encountering grasshoppers, humming birds and then a rattlesnake that attempts to eat the baby bird. The bird manages to lead the snake into tying itself
Evolution of birds evolved into some basic lineages by the end of the Cretaceous (see "Vegavis"). The Neornithes are split into the paleognaths and neognaths. The paleognaths include the tinamous (found only in Central and South America) and the ratites, which nowadays are found almost exclusively on the Southern Hemisphere. The ratites are large flightless birds, and include ostriches, rheas, cassowaries, kiwis and emus. A few scientists propose that the ratites represent an artificial grouping of birds which have independently lost the ability to fly in a number of unrelated lineages. In any case, the available data regarding their evolution is still very