have feathers

Feathers do a number of things. They protect a bird's skin from wet, cold and injury; their colors and shape play a large role in attracting a mate; and of course, feathers allow a bird to fly.

Feathers are made up of the protein keratin (the same substance found in our hair, teeth and nails). They are lightweight enough to allow the bird to fly, yet are also strong and waterproof.

can fly
(well most birds any way)

Most birds fly (and those that don't, like emus, descended from ancestors who flew). This amazing behavior is the product of numerous body adaptations. Birds' front limbs have evolved into wings.

Their bones are "hollow" (honeycombed with cells of air) to make them light enough for flight. Birds have also evolved a keel-shaped breastbone, which provides an anchor for the wing muscles that power their flight.