The Bower birds of Australia and New Guinea are known and studied for their curious mating ritual. Sixteen of the twenty species of male bower birds build elaborate structures to woo their female counterparts. The “bowers” are built with usual nesting materials; moss, twigs etc., but the decorations they adorn them with vary significantly. Bowers use flower petals, stones, berries, beetle wings and any other oddity they can carry. The male birds are meticulous in their maintenance of the decorations, if one piece is jostled out of place (usually by a neighboring male); the owner of the bower quickly repairs it. The birds are polygynous and may mate with many females. Bowers are built in the same place annually which makes it easier for returning females to find an established male.
Bowers are an elusive species and less than half have been photographed. The mating act is rarely witnessed. When a male spots a female in the vicinity he’ll let out a song or a clicking call. When he has the female's attention, some of the species will commit a peculiar act, they’ll hide. When the female lands on the stage of the bower, the male will erect colorful plumage from the back of the neck, spread its wings and jerk out a dance, often using the tree or bower, as an obstruction. If the female is interested, they will fly off into the bush to consecrate the union. Then the female builds a nest nearby and raises the offspring by herself. An established male will mate with up to seventy five percent of the females in their area. Despite numerous other bowers by younger, less established males in close proximity.
This brief synopsis can explain why the bower bird was so fascinating for the fantastic genetic illuminant, Charles Darwin. In chapter fourteen of Descent of Man, he discusses why female birds choose a male. The bower bird is of significance because they are the only species to present a stage and treasures for the female. While males of the same species are sometimes drawn and enamored by similar materials and colors of the objects, often the arrangements and materials differ. Darwin wondered why one male bower could mate with many females, when in close proximity (10 bowers in a square kilometer), many other bowers with pleasing aesthetics would be overlooked by the females.
What is it about a particular male that makes the females go crazy? The studies have primarily focused on the male variables; dance, bower size and adornments. The female bowers are elusive and are more difficult to study. Since the males maintain their bowers and remain in a fixed area year after year, the bowers are the only definitive place to view the birds. Conclusions are difficult to discern, but the size, shape and adornment of the bower and the meticulous care of the owner is the widely accepted theory of why a certain male mates with such a vast majority of the females. Further research on dance and song were conducted by the University of Maryland. The study used robotic females to entice males to display. The study was used with the most widely known bower, the Satin bower bird. The research is still being interpreted but early data indicates that male birds will mate with any female, even the robotic ones. Dr. Geraldo Borgia is the head of the bower studies at the University. He is the contemporary guru on the subject and offers most of the research in the field today.
There are three types of bowers.
- Mats. These mats are typical of bowers with bright plumage. The mat is generally a platform of twigs encircled by treasures.
- Maypole. These are the largest and most elaborate structures. The birds use a small tree and build a mound of moss and dirt around it. They hang lichen, moss and even caterpillar droppings from the twigs. Some species build a platform in the air between two trees. These twig towers can take up to nine months to construct and can be up to two meters tall.
- Avenues. These bowers are diverse and usually contain the most treasures. Built on the ground, they consist of twigs stuck together to form a runway of sorts. All bowers have avenues, but these are specifically constructed to suit the dance of the certain male.
Drab species often build large monstrosities, while the bright plumed species may only use leaves to decorate. The correlation of these variables is what makes the bower bird so fascinating. Males use extraneous elements to aid in the mating ritual
Many of the birds have never been seen or photographed, certain species have not been studied. This list does not contain the four catbirds that do not build bowers. Listed by species.
Genus Amblyornis The maypole builders.
- flavifrons - Golden fronted bowerbird
- subalaris - Streaked bowerbird
- macgregoriae - MacGregor’s bowerbird has orange to red rust plumage and hangs berries, special caterpillar droppings and yellow moss in nearby trees as pendants. A ring formed around the maypole is made of impacted moss and black fungus and yellow jasmine flower petals are often draped around the mound.
- inoratus - Vogelkop bowerbird is found in the Arfak Mountains on the Vogelkop Peninsula in western New Guinea. It is a drab bird that builds a bower that typically takes nine to ten months to construct. The bower is cave like and the treasures can be exorbitant. They can pave a three meter patch of ground with extensive stripe mosaics of silver shells, green moss and red berries. .
- sanfordi - Tomba bowerbird
- papuensis - Archibald bowerbird is a mat builder and adorns with shells and beetle wings. It has large retractable head plumes.
- cerviniventris - Fawn breasted bowerbird
- guttata - Western bowerbird is an avenue builder that prefers white objects like bone and has a deep velvet plumage.
- lauterbachi - yellow breasted bowerbird
- maculate - Spotted bowerbird builds a wide straw wall it uses to hide and seek dramatic poses and a wild display. Uses fresh, bright leaves to decorate.
- nuchalis - Great bowerbird uses white and orange to decorate.
- newtoniana - Golden bowerbird, the smallest, builds a roofed bower suspended between two maypoles which reach heights up to two meters. Additions are built each year so the bigger bowers often belong to the oldest males. Real estate is important with this bower, if a structure is destroyed, a male will reconstruct the entire bower in lieu of moving to a new spot and losing the females that return each year. The preferred treasures are green orchids, seed pods and lichen.
- violaceus - Satin bowerbird. The Satin bower is the most well known and documented of the birds. It is found in urban areas of Australia and is a wonder for delight in all things shiny and blue. This is an avenue builder that constructs two parallel walls of twigs stuck in the ground to form a chute for the female to go into. It uses chewed berries to paint the interior. It has a deep indigo color and uses a similar color as a favorite to drop around the bower. It often shows the rather unusual treasures to the female by picking them up in his beak.
- aureus - Flame bowerbird is found in the mid elevations of New Guinea.
- bakeri - Fire bowerbird
- chrysocephalus - Regent bowerbird. The regent also paints the bower using chewed plants, charcoal and spit. It is brightly colored orange and black. Aside from the painting, the bower is a simple mat with leaves surrounding it, light side up.
Two documentaries are the Nature program, “Bower Bird Blues” and Nova, “Flying Casanovas”.