y do some birds fly when others ..

Brief：
Answers: i head that birds * al the time so they hav less weight to carry when they fly. so maybe the flightless ones hav constipation not all birds h.. 

Answers:

i head that birds * al the time so they hav less weight to carry when they fly.

so maybe the flightless ones hav constipation not all birds have hollow bones - "we all have wings , but some of us don't know why" Because "bird" doesn't exactly mean that it has to fly.. and because some are too heavy with too small wings. Some are lazy-- weight Penguins don't fly because they refuse to conform (which is funny because they all look alike.) to bird laws, and instead of flying they swim. The birds can fly if there feathers could flap harder against the weight of their body to push wind whish flows towards the direction they flys!

If the birds wieght is high than the speed of the wind it can't fly lke others does~ just cuz some don't like too some way to much for their wings to carry them Hurt wing