A bird beak is the most important resource it has, and every species has one solely designed for survival. Birds use beaks for just about everything: building nests, feeding their young ...

Under these drastically changing conditions, the struggle to survive favored the larger birds with deep, strong beaks for opening the hard seeds. Smaller finches with less-powerful beaks perished.

They form lifelong bonds with mates, share food and engage in mutual grooming. Macaws have powerful beaks for cracking nuts, eyes that change color as they age and complex emotional lives, including ...