Bowerbirds build with visual tricks to woo mates, and they don’t want help.
by Jennifer S. Holland
Sometimes love is an illusion. Especially if you’re a bowerbird.
These crow kin from Australia and New Guinea are known for constructing elaborate edifices to woo mates. But males of one species, the great bowerbird (Ptilonorhynchus nuchalis), go a step further: They use a trick of architectural perspective to boost their allure, and will stick to their own scheme even if it falls short with the females.
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…