A few days ago, I came across the bizarre courting rituals of bowerbirds and decided to expand my knowledge on the topic. I could not find any amazing, copyright free images of their exquisite edifices, so I would highly recommend checking out the aforementioned article and googling bowerbirds. The article lists several types of bowerbird species and elaborates briefly on their courtship rituals. In general, all bowerbirds construct a type of display stage or “bower” to woo a female. However, this is no simple task.
Great bowerbirds and satin bowerbirds use unusual and colorful objects to adorn their bowerbird bachelor pads. Conversely, the golden-fronted bowerbird prefers to decorate with colorful fruits. Despite its mundane plumage, the Vogelkop bowerbird produces some breathtaking designs by predominantly utilizing fruits and flowers. Moreover, the Vogelkop performs an extensive repertoire of mimicry noises, which are amplified by the cave-like structure of their bower. Interestingly, regent bowerbirds have a blue-green saliva mixture that they can add to their bower abodes to help attract females. I thought one of the most bizarre aspects of my search was discovering that orange flame bowerbirds can control the dilation of their pupils and can even change their sizes asynchronously! A lot of these courting rituals sound a little too crazy to believe, so I included video links to three of my favorites:
Satin bowerbird and lady friend: Bowerbird Woos Female with Ring (Nat Geo WILD)
Orange flame bowerbird (with crazy eyes!): The Bowerbird’s Grand Performance! (BBC) *This was my favorite video because of the bizarre nature of the courtship dance, and, as an added bonus, it is narrated by David Attenborough!
The Vogelkop Bowerbird: Nature’s Great Seducer (BBC) *I liked the color composition of the bower decoration and the cave-like bower structure. My affinity for this bower type may stem from the fact that I have been watching too much Project Runway on German Netflix lately…
Another aspect that I found interesting about the bower construction is that, evidently, great bowerbirds use geometry and “forced perspective” to make their bower more appealing (Bowerbirds Use Geometry to Woo Females [Nat Geo]). The males will organize their bower decorations so that larger items are at the very edges of their bower, and smaller items are closer to the center of their bower. Consequently, when the female is situated inside the bower archway, she is under the illusion that she sees an “evenly textured stage.” Males with the most uniform stages tend to get the girl.
I was concerned reading through articles about bowerbirds that incorporate plastic into their bower design. I could not find any great articles about how the usage of plastic debris in bird nests has evolved over time, which was disappointing. If anyone knows of any, please share! I do not have endless time to comb the internet… I did find one scientific article about seabirds: The use of plastic debris as nesting material by a colonial seabird and associated entanglement mortality. The article focuses on northern gannets and states that an average of 469.9 grams of plastic debris (primarily synthetic rope) is used as nesting material. The use of plastic within the nests also led to an average of about 62 birds, mainly nestlings, dying each year because of entanglement in nesting material. Staying with this topic, other research also shows that birds incorporate manmade plastics to show territorial dominance (Nest Garbage Says, ‘Keep Out!’ [Science Magazine]). I find it disheartening that manmade items are so prevalent in nature now that wildlife is beginning to integrate debris into the core of their existence and that adapting to it is essential to their survival.
The gannet study relates back to a post that I recently saw about people putting out nesting materials for birds. Numerous websites recommend setting out extra, manmade nesting materials for our avian friends, such as yarn or string. However, the gannet study indicates that there needs to be a re-evaluation of this seemingly helpful gesture. It may be doing more harm than good. If you feel the urge to provide nest materials for your feathered friends, stick to organic materials like straw, dried grasses, and twigs. Have a great weekend!
Satin bowerbird bower by gailhampshire (Cradley, Malvern, UK) CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=49951624