Question

What are the changes in bird bodies that the adopt them to serial habitat

Answer 1

Flight feathers — specifically shaped feathers that provide lift and reduce drag.
A huge keelbone for anchoring flight muscles.

Fused fingerbones creating a strong anchor for flight feathers, and longer, strong front limbs.

Pretty much everything else (including hollow bones and a wishbone) evolved prior to any flying or gliding, for other reasons, so don’t represent a significant change to adapt to flight.