Because mammals can't really use blue camouflage against things that aren't the sky (or water, i.e. whales). Birds are frequently high up, so they blend in with the blue sky. Some kind of adaptation.
no, blue penguins are not mammals they are birds and they are also grayish blue
No Herons are birds and birds are not mammals. Mammals feed their young on milk secreted by mammary glands.
Other fish, birds sharks, and mammals eat blue angelfish
no, rats are mammals and blue penguins are birds, they are totally unrelated
it is a vertebrate
Yes all birds can fly except ostriches and penguins
all birds are unable to see the colour blue... except the owl! :P
Cats, like most mammals (except primates and man is a primate) see only green and blue colors, but they depend mostly on their black/white vision. Primates see 3 colors, red green and blue. Birds and insects see 4 colors, red green blue and ultraviolet.
Blue jays are birds, not mammals. Only mammals nurse, or provide milk for their young. However, blue jays do take care of their hatchlings, and feed them regurgitated food.
Mammals are warm blooded, bear live young, nurse their young, and have hair (of some sort ) at least at some time in their lives. Penguins are animals, BUT not mammals. They are birds, although they swim rather than fly. Birds have feathers (although the penguins' are furry-like in feel) and lay eggs. Like mammals, birds have a backbone and are warm-blooded. Some mammals do lay eggs, like the Platypus, or the spiny echidna. But most bear live young.
Blue birds live all over the world except for in some types of the world
Coyotes and bears mainly eat them. Also sometimes large birds such as the great blue heron eat them.