Like all other reptiles, birds have scales. Also, birds lay eggs like other reptiles.
Gene flow does not promote speciation, whereas season of fertility, natural selection, and genetic drift do.
The northern hemisphere is warmer in the summer than the winter because the northern hemisphere are pointing toward the sun. Because of this the rays hit us more directly making is hotter. So during the winter when the northern hemisphere is not pointing toward us, it makes is colder. It also depends on the tilt of the axis. When it is more direct it makes the temperature hotter.
Can you give anymore information?
