By Jason Bittel
In most North American hummingbirds, males court females by diving at them head on — but Costa’s hummingbirds (Calypte costae) perform their courtship dives off to the side. Researchers now find that this strategy allows the males to aim sounds at potential mates as if they were using a megaphone.
During high-speed courtship dives, males fan their tails at the last second to create a high-pitched chirp. The faster the dive, the more those tail feathers vibrate and the higher the pitch created by the would-be Romeos. Researchers suspect that females prefer higher-pitched dives, which results in various strategies to boost the frequency of the noise a male makes.
A study1 published on 12 April in Current Biology finds that male Costa’s hummingbirds can twist half of their tail feathers in the direction of the female, manipulating the volume and pitch of their chirps (see video). The researchers suspect that the targeted noise also masks audio cues that the females can use to judge how fast the males are diving.
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