Female bowerbirds are responsible for building nests in trees to lay eggs and raise their young alone, but it is the male bowerbirds who go to great lengths to build elaborately constructed and decorated “bowers”—or love nests—on the ground, some up to seven feet tall, to attract a series of mates.
Satin Bowerbird is Most Recognized
There are 18 species of bowerbirds that live in a variety of habitats in Australia and the island of New Guinea to the north, including woodlands, rainforests, and cloud forests at high elevations. They vary in size and color, and the shape of features such as their bills, crests and tails.
People often think of the male Satin bowerbird (Ptilonorhynchus violaceus) of eastern Australia when they picture a bowerbird. It has a large, approximately 12-inch long body with shimmery dark plumage that reflects blues and purples in the sunlight. The female of this species is a duller gray-green.
How the Bird Constructs His Bower
Most bowerbirds construct their bowers in a cleared area on the ground, about three to five feet wide. It may take weeks to create the structure, made of thousands of twigs. Individual species’ bowers may resemble tall maypoles, low huts, or in the case of the Satin bowerbird, a tunnel-like “avenue” of twigs. Unlike bowers which have a roof, the Satin bowerbird’s structure is made of high walls of sticks held together by a mixture of saliva and fruit pulp.
The birds decorate their bowers with items from the environment, such as leaves, flowers, berries, feathers, iridescent insect skeletons, colored stones, kangaroo bones and snail shells; trash like blue plastic, paper and glass; and items poached from human abodes such as hair curlers and car keys. Objects collected for decoration are often blue, and in today’s world it is quite common to see that the birds have collected blue plastic bottle caps. Each species has its own decorating preferences.
Bowerbirds Resort to Thievery
There is a fairly certain correlation between the complexity of the bird’s plumage and the complexity of the bower he creates. According to Irby Lovette at the Cornell Lab of Ornithology in New York, who wrote the spring 2008 article called “Stealing from the Neighbors,” Australian researchers have found that the most prized decorations for the male’s bower are the blue plastic bottle caps and the “azure tail feathers of Crimson and Eastern Rosella parakeets.”
Since many decorations are in short supply, bowerbirds resort to stealing from other males. Lovette explains that the birds with the most decorated bowers were also found to be the biggest thieves. However, those birds also became victims of theft when they left their bowers unguarded. Even though the most decorated bowers typically attract more female attention, a female bowerbird often don’t care about the showy displays, and will enter a humble bower just as she will a fancy one.
Completing the Display
The bower alone won’t attract females to the male bowerbird’s love nest. The male will stand outside of it and call loudly, make a variety of other sounds, do a dance, flutter his wings, jerk his head about, among other things, depending on his species. Fortunately the female bowerbirds are fully capable of creating more practical, protected nests in which to raise their young as single mothers, because once the mating dance is over, the male moves on to the next conquest, taking no part in the future of his offspring.
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