Why do YOU think some birds can fly?
They're small enough.
% (43 votes)
They're light enough.
% (137 votes)
They have big wings.
% (83 votes)
They have big feathers.
% (49 votes)
They have hollow bones.
% (192 votes)
They have a special muscle.
% (176 votes)
Back to poll
votes
Powered by StrawPoll