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.

“normal” beaks (examples shown of a petrel and a gull) and a bird with a tactile bill-tip organ (a tinamou, close relative of ostriches and emus and which has an ancestral bill-tip organ ...

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 ...

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 ...