birds of a feather

Our Living Language  : It is generally believed that birds are descended from dinosaurs and probably evolved from them during the Jurassic Period. While most paleontologists believe that birds evolved from a small dinosaur called the theropod, which in turn evolved from the thecodont, a reptile from the Triassic Period, other paleontologists believe that birds and dinosaurs both evolved from the thecodont. There are some who even consider the bird to be an actual dinosaur. According to this view, the bird is an avian dinosaur, and the older dinosaur a nonavian dinosaur. Although there are variations of thought on the exact evolution of birds, the similarities between birds and dinosaurs are striking and undeniable. Small meat-eating dinosaurs and primitive birds share about twenty characteristics that neither group shares with any other kind of animal; these include tubular bones, the position of the pelvis, the shape of the shoulder blades, a wishbone-shaped collarbone, and the structure of the eggs. Dinosaurs had scales, and birds have modified scales—their feathers—and scaly feet. Some dinosaurs also may have had feathers; a recently discovered fossil of a small dinosaur indicates that it had a featherlike covering. In fact, some primitive fossil birds and small meat-eating dinosaurs are so similar that it is difficult to tell them apart based on their skeletons alone.

bird definition

1. n.
   a woman; a girl. : I like the bird you were with last night.
2. n.
   a derisive noise made with the lips; a raspberry. : The third time he fumbled, he was greeted by two thousand mouths making the bird.
3. n.
   an odd person. : Some old bird came up to me and tried to sell me a cookbook.
4. n.
   a rude gesture made with the middle finger. (Usually with the. See comments at finger wave.) : A lot of little kids give people the bird all the time because they see it on television.
5. n.
   an airplane. : I like this bird. She's a dream to fly.

birds of a feather definition

1. phr. & comp. abb.
   people who share an interest or proclivity. : Those guys are really birds of a feather. They are always together. , We're BOF and love to hike and enjoy nature.