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.

A bird beak is the most important resource it has, and every species has one solely designed for survival. Birds use beaks ...

But why is a barred owl more of a baritone, while a cedar waxwing is a soprano? And what influences a bird’s vocal range, and the kinds of sounds it can make? Beak size? Body size? Geography? To ...