Unsual mating rituals are emerging in modern times. In a bizarre wild twist, a female great bowerbird can be won over by a pair of handcuffs, discarded medicine jars, or a neon football mouthguard.

A new study shows that urban male bowerbirds are ditching otherwise natural decorations and turning to a wild assortment of human trash to woo mates.

Researchers from the University of Exeter compared birds in Townsville City to their rural counterparts in Queensland, Australia.

It was discovered that urban displays featured much more vivid reds and duller greens than their rural counterparts

“Our study demonstrates that availability of human items – often glass and plastic – is affecting the behavior of bowerbirds,” said Dr Laura Kelley from the University of Exeter. 

“We don’t yet know whether this has any negative or positive impact on them, but it’s a reminder of how human activity is changing the natural world in unanticipated ways,” Kelley said.   

City birds ditch nature

Male bowerbirds do not help raise young. Their only goal is to attract a mate. To do this, these avians build a special tunnel of twigs called a bower and surround it with a courtyard of colorful objects. When a female visits, the male throws objects into her line of sight while flaunting his colorful plumage.

In the wild, this means typically collecting berries, seeds, leaves, and other such natural items. In the city? It means raiding the local stadium.

“Bowers are built exclusively to attract a mate, and males choose decorations that contrast against their own plumage and the bower itself,” said Caitlin Evans from the Center for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall.

“Our findings show that bowerbirds in a city use a wide range of items scavenged from humans. Glass, plastic, and wire were common choices, but we also found items including a pair of handcuffs, medicine jars at bowers near a hospital, and fluorescent mouth guards from a site near an Australian Rules football ground,” Evans added. 

Overachiever bird

Urban bowerbirds are prolific collectors, hoarding an average of 90 items per bower — with one overachiever amassing more than 300. In comparison, the average was a modest 20 items for rural males. 

The researchers also evaluated the bowers through the eyes of the female birds. Bowerbirds have incredible vision, and their eyes are much more sensitive to color than human eyes.

Interestingly, the birds’ choice of décor also reflects their surroundings. While rural birds rely on green leaves, seeds, and occasional green glass, city birds heavily favor synthetic, high-contrast materials, making green glass and red wire their top two decorations.

To test how deep this preference runs, the team set up a swap experiment. They offered both city and country birds a mix of natural and human-made items. The choice was unanimous.

Both groups overwhelmingly chose the human-made plastic and glass. Even the rural birds were willing to raid farm garages and trash bins to upgrade their collections.

However, the study did not directly measure female preference. The intense enthusiasm city males for hoarding these human objects likley suggests that the females find them attractive.

Whether this helps the birds win more dates or accidentally introduces environmental risks is a question scientists are still trying to solve

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