A Game of Bowers

While Michele has described the efforts of our local Satin Bowerbirds in attracting a love interest, in the surrounding forest another Bowerbird, the Golden Bowerbird (Prionodura newtoniana), is also busy constructing bowers that are the largest of the all the Australian bowerbirds, and they are made by the smallest species. Despite its diminutive size, the Golden Bowerbird creates twin towers of twigs that can be up to 3m tall. It decorates them with lichen and pale cream flowers and places a horizontal stick between the base of the towers to serve as a display perch.

Golden Bowerbird at his bower

The bower. The perch is the small stick just visible near the bottom. Note that this picture was taken a week after the previous shot and the lichen ornamentation has been shifted by the male.
The male often perches in a nearby tree looking out for females or other marauding males

It takes a fair bit of work to make these bowers and it turns out that other males (including young males still experimenting at bower-building) are prone to stealing material and ornaments from other bowers to build their own. Immature males sometimes build small bowers close to a more established structure in the hope that they can distract a female over to its more humble edifice while the dominant male is away foraging or stealing from other bowers. If a mature bower-owning bird dies, his bower is usually taken over by another bird in matter of days. One recent study used game theory to determine at what point the pay-off from raiding other birds bowers exceeded the risk of abandoning a bower to other marauding males (distance between bowers was a key factor). The competition and intrigue is worthy of a Game of Thrones plot-line.

An immature male Golden Bowerbird discretely approaching the bower
Immature male at the bower just before being attacked by the resident male

Last week, while photographing one of our local birds, I observed a small dull bird flitting ever closer to the bower through some dense foliage. I thought it might be a female, but I was able to get a shot of it as it took off from a branch just behind the bower and this clearly showed the yellow tinges to the wing that are diagnostic of an immature male. This immature male then went straight to the perch between the two towers of the bower and began inspecting the ornamentation. In a flash the mature male bower owner dived down and the two birds tumbled off into the ground foliage behind the bower in a flurry of feathers and screeches that lasted several seconds before the birds flew off in different directions. The younger bird was not seen again, but I can’t help but feel it is out there somewhere awaiting another chance to steal the throne and the females.

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A small single towered bower made by an immature male less that 15m from the established bower

Don Battersby is our local bird-whisperer -actually it’s more of a shout, but the birds certainly come flocking to his call. When I told him about my observations he regaled me with a complete history of this particular bower, which has occupied at least 4 different positions over the last decade or so, having been abandoned due to damage by tree-falls or in response to over-enthusiastic bird photographers. He was also kind enough to show me a small satellite bower near the site where I had witnessed the altercation. This might well have been built by the immature male that I had seen.

Don knows where virtually all the bowers, and some of the nests are. He is exceptionally generous with his time and is known nationally and internationally amongst “birdos” as the person to visit if you want to get good views and photographs of our rainforest birds. Thanks Don!

Text and photos by Jamie Oliver

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