While most bowerbirds embellish their "love nests" with bright, shiny baubles, the great bowerbird's decor is comparatively bland: an avenue of sticks leading to a pair of courts garnished with mostly gray-to-white objects like pebbles, shells, and bones.
But a lack of color doesn't mean a lack of style for these birds. Biologists John Endler and Laura Kelley of Australia's Deakin University have found that male great bowerbirds carefully arrange their courts' decorations in a specific pattern, with bigger items farther away from the bower avenue (where the female stands), creating the illusion of an evenly textured stage.
This effect—called "forced perspective"—may be visually pleasing to the female, or it may simply make the male, who waves colored objects during his mating dance, easier to see. Whatever the reason, the males who build the most geometric patterns also have the most success in winning mates.
Jennifer S. Holland, National Geographic News/December 3, 2012, here.
From Rick Gordon