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.

Birds are perhaps the most diversified creatures ... Yellow-billed Kingfisher (Syma torotoro) Orange head, yellow-orange beak, olive-green wings, found in New Guinea and northern Australia.

Male house finches are more orange and red with the color concentrated ... with two white stripes stretching from their beaks ...

Over time, natural selection favored finches with sharper, longer beaks. These birds were better equipped to quickly and easily pierce the skin of their booby bird neighbors. Vampire finches still ...

The two-colour discs had different pairs of colours selected from an orange-to-red spectrum. This mirrors the colour range found in the male songbird beak. One idea was that the birds would be ...