Dive-bombing for love: Male hummingbirds dazzle females with a highly synchronized display

Date:  December 18, 2018

Source:  Princeton University

When it comes to flirting, animals know how to put on a show. In the bird world, males often go to great lengths to attract female attention, like peacocks shaking their tail feathers and manakins performing complex dance moves. These behaviors often stimulate multiple senses, making them hard for biologists to quantify.

Hummingbirds are no exception when it comes to snazzy performances, as males of many species perform spectacular courtship dives. Broad-tailed hummingbirds (Selasphorus platycercus) fly up to 100 feet in the air before sweeping down toward a perched female, then climb back up for a subsequent dive in the opposite direction. At the Rocky Mountain Biological Laboratory in Gothic, Colorado, home to a population of breeding broad-tailed hummingbirds, researchers from Princeton University have been investigating how hummingbirds combine speed, sound and color in their displays. Their work appears in the Dec. 18 issue of the journal Nature Communications.

"The dives are truly amazing feats for such small birds," said Benedict Hogan, a postdoctoral research associate in ecology and evolutionary biology and the study's lead author. "We know from previous work that the males can reach really high speeds. They combine that speed with intriguing noises generated by their wing and tail feathers, and of course with their brightly iridescent plumage." But how do these different components fit together, and what might a dive sound like and look like to a female?

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Couples showing off: Songbirds are more passionate in front of an audience

Date:  October 3, 2018

Source:  Hokkaido University

Both sexes of a songbird called the blue-capped cordon-bleu intensify courtship performances that involve singing and dancing in the presence of an audience, especially if it is a member of the opposite sex, an international team of researchers has discovered.

Mutual courtship displays have generally been understood as a form of private communication between a male and a female, and many researchers have focused on this aspect. The cordon-bleu is a socially monogamous songbird found in Africa. In its courtship display, both sexes sing and sometimes add a unique dance that resembles tap dancing.

Birds that live in flocks like cordon-bleus are thought to carry out courtship communications in the presence of other birds. However, very little research has been conducted on whether the individuals performing courtship displays are influenced by the presence of other birds. In the present study published in Science Advances, researchers from Hokkaido University in Japan and the Max Planck Institute for Ornithology in Seewiesen, Germany, focused on this so-called audience effect.

In the experiment, the researchers placed paired couples in situations with and without an audience and observed their behavior.

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