Basics of Bowers

Bowers are usually divided into two types: maypole bowers and avenue bowers. Bowers vary significantly from species to species. In some species they can reach about 5 feet in height (Borgia 1996). The walls of the bowers are painted with masticated pine hoop needles (Hicks et al. 2013). Bowers and their adjacent display courts can contain thousands of brightly colored decorations (Borgia 1996), which include objects such as shells, flowers, feathers, shards of glass, and pieces of plastic. These decorations are usually of a particular color which can vary among species. For example, the satin bowerbird demonstrates a strong preference for blue (Savard et al. 2011). Some species utilize a forced perspective optical illusion, where the objects are arranged from smallest to largest (Doerr & Endler, 2015).

Maypole Bowers

Maypole bowers consist of a sapling, or “pole”, surrounded by a circular display court, with sticks usually being stacked around the sapling. The Macgregor’s bowerbird builds the simplest maypole structure. It surrounds a thin sapling with horizontal piles of sticks and the court is covered with a compressed-moss mat (Borgia 1998). It then decorates its structure, like all other bowerbirds. Some maypole bower-builders use two spires rather than one, connecting them with more sticks. Other maypole bower-builders have structures resembling huts.

       Bower of the Macgregor’s bowerbird                                        Bower of the Vogelkop bowerbird                

Bower of the Macgregor's bowerbird                Bower of the Vogelkop bowerbird

Avenue Bowers

Avenue bowers consist of two parallel walls of vertically placed sticks, along with adjacent display courts on either end of the structure. The space between the two walls is known as the central avenue, which is typically slightly wider than the width of the individual. 8 species of bowerbird build this type of bower (Borgia 1998), 3 well-researched ones being the satin bowerbird, the great bowerbird, and the spotted bowerbird. Although the bowers of these three species each have their own unique features, that of the spotted bowerbird is known for being exceptionally different from those of the other avenue bower species.

Bowers of satin bowerbirds

Satin bowerbirds construct their bowers entirely out of densely packed sticks. The walls bulge outward near the base then curve back inward toward the top. The bowers are oriented such that the main axis runs north to south. Decorations are heavily concentrated in the northern court. Satin bowerbirds usually have the courts uncovered, but the bowers and courts are generally surrounded by vegetation, with a log characteristically situated behind the south bower (Borgia 1995).

Bower of the satin bowerbird

Bower of the satin bowerbird

Bowers of great bowerbirds

The bowers of great bowerbirds are similar in many ways to those of satin bowerbirds. They are constructed entirely out of densely packed sticks, have walls that bulge outward near the base and curve inward near the top, and have a main axis running from north to south. Unlike satin bowerbirds, however, great bowerbirds distribute decorations equally between the two display courts on either side of the bower. Another difference is in location: great bowerbirds usually have the display court and bower entrance on one side partially enclosed within a bush (Borgia 1995).

Bower of the great bowerbird

Bower of the great bowerbird

Bowers of spotted bowerbirds

Spotted bowerbirds construct their bowers primarily out of straw, which is inserted into a base of sticks. This makes the walls highly see-through. Their bowers do not have significant curvature, and are oriented such that the main axis runs east to west. Like great bowerbirds, spotted bowerbirds distribute decorations equally between the two display courts. However, they are far more dispersed, with the distances between decorations along the main axis of the bower being more than twice as large as those in either great or satin bowerbirds. The bowers are also unique in that the central avenue is twice as wide as would be expected for the individuals’ body size. Spotted bowerbird bowers are usually not near dense vegetation, although they are often situated under a tree (Borgia 1995).

Bower of the spotted bowerbird

Bower of the spotted bowerbird