How A Hummingbird Uses It's Tail To Serenade the Ladies

Male Costa’s hummingbirds court females using a high-speed dive in which they sing with their tail feathers.

Credit: Christopher Clark, UC Riverside.

The findings suggest that males can strategically manipulate the way females perceive their displays by minimizing the Doppler sound. This deprives females of an acoustic indicator that would otherwise reveal the speed of their dives.

“Recent studies in birds and other animals suggest that females prefer higher speeds during male athletic displays. By concealing their speed, males are not necessarily cheating, but instead have evolved this placement of trajectory out of female choice,” said Christopher Clark, who led the study. Clark is an assistant professor of biology in UCR’s College of Natural and Agricultural Sciences.

Clark and co-author Emily Mistick, a former research assistant at UCR, showed that males aim their sound toward potential mates by twisting their tail vertically by up to 90 degrees. In previous research, Clark has shown that the tail song is made by the flutter of the outer tail feathers.

“We don’t know why males twist only half of their tails toward the females, but it may be due to anatomical limitations that prevent them from twisting their whole tail around,” Clark said.

Credit: Univ. of California, Riverside

 

Clark and Mistick used a device called an acoustic camera to record Costa’s dives. They also conducted experiments in a wind tunnel to examine how the birds’ speed and direction influence the sounds they make. Curiously, they found it was difficult to measure the velocity of the Costa’s dive from the sound produced.

“Once I realized it wasn’t trivial for a scientist to measure, I realized it wouldn’t be trivial for a female to measure either,” Clark said.

Clark said the findings add to the literature about how male animals use athletic displays to attract females.

“Most research has focused on static male attributes, such as bright colors or elongated tails, but our research shows that dynamic displays may be just as important, and males strategically control these performances to show themselves in the best possible light,” Clark said.

 

 

Contacts and sources:
University of California, Riverside

Citation: Strategic Acoustic Control of a Hummingbird Courtship Dive Authors:   Christopher J. Clark, Emily A. Mistick  Current Biology