In many species of birds, the males are far showier than the females. Males of some species might possess colorful plumage or exaggerated physical features to catch a female’s eye, while males of other species may perform elaborate mating dances to wow potential mates.
There is one group of birds, however, whose males have a rather odd method of capturing the attention of passing females. These impressive birds, found in parts of New Guinea and Australia, are called Bowerbirds. They get their name from the unique structures called bowers that males create to impress their female counterparts.
The term “bower” itself is not synonymous with nest, but refers instead to a structure created specifically for use in attracting and courting mates. The simplest of bowers are narrow tunnels or avenues constructed of sticks and decorated with shell and bone. The entrance tunnels of more elaborate bowers lead to an “arena” or “court” filled with carefully selected items which are often arranged in piles by color and shape.
These items can include anything from shells, small bones, flowers, and fruits, to items such as bottle caps, pieces of glass, and other trash items. Bowers may seem simple at first glance, but if one takes a closer look, it becomes obvious just how much color and geometry play a part in bower construction.
Many male Bowerbirds use color illusions to make their collected items seem more visually impressive. They often achieve this by chewing up red objects such as fruit or flowers into small pieces and lining their bower completely. After the female has stared at the red lining for a period of time, the green and blue items in the bower may appear more striking.
In addition to color, geometry plays a large role in a bower. In terms of item size, male Bowerbirds may purposefully pile larger pieces furthest from the entrance and will place smaller pieces closer to the entrance. This counteracts the usual visual phenomenon in which items further away may appear smaller and items closer seem larger. Additionally, the narrow entrance tunnel focuses attention into the bower. These two illusions help make the male Bowerbird look larger and more impressive to visiting females.
The male Bowerbird may also pick up particular items to show to the female to impress her even further. The object may be pleasing in color, or the dimensions of the object may add to the Bowerbird’s clever body size deception.
After male Bowerbirds perform their series of strutting, vocalizing, and showing off their bower, females will choose whether or not to accept their invitation based on how impressed they were by the display. Males most often will mate with multiple females throughout the breeding season if possible, which makes sense given that bowers must be time consuming and tedious to construct! To increase their chances, male Bowerbirds have often been known to resort to foul play and destroy bowers of other males.
Of all of the courtship behaviors exhibited by different species of birds, bower building is definitely one of the most odd and unique. The cunning and deceptive behavior of the male Bowerbird serves as a great example of one of many amazing courtship practices that can be observed in the bird kingdom.
