How Costa’s Hummingbirds Create the Sound of Their Courtship Dive

Apr 30

Scientists continue to uncover remarkable details about hummingbird behavior, and some of the most fascinating discoveries involve their courtship displays. Male hummingbirds often perform elaborate aerial dives designed to impress females, but these displays are more than just dramatic flight maneuvers.

A study published in the journal Proceedings of the Royal Society B explored how male Costa’s hummingbirds (Calypte costae) produce the distinctive sounds heard during their courtship dives. The research reveals that these sounds are not vocal calls at all. Instead, they are produced by air moving across specialized tail feathers during the dive.

For those who have watched hummingbirds in the field, this research helps explain the sharp chirping or buzzing sounds sometimes heard as a male bird sweeps past during a display flight.

The Spectacular Dive Display

During the breeding season, male Costa’s hummingbirds perform an aerial display that involves climbing high into the air before diving steeply toward a female.

The display typically includes:

a rapid upward climb
a steep dive toward the ground
a loud chirping sound near the lowest point of the dive

These displays can be repeated multiple times as the male attempts to attract the attention of a female.

For years, scientists debated whether the sound heard during the dive was produced by the bird’s voice or by its feathers.

Investigating the Source of the Sound

To answer this question, researchers studied the dive displays of Costa’s hummingbirds using high-speed video and acoustic recordings.

The scientists carefully analyzed:

the speed of the diving bird
the position of the tail feathers
the timing of the sound produced during the dive

They also examined the shape and structure of the hummingbird’s tail feathers.

Their observations revealed that the sound occurs precisely when air flows rapidly across specific outer tail feathers.

Tail Feathers That Produce Sound

The research showed that specialized tail feathers act almost like tiny musical instruments.

As the bird reaches high speeds during its dive, air rushing past the outer tail feathers causes them to vibrate. This vibration produces the characteristic chirping sound heard during the display.

In Costa’s hummingbirds, the third outer tail feather appears to play a particularly important role in generating this sound.

The feather’s shape and stiffness allow it to flutter at specific frequencies as air passes over it.

Controlling the Sound of the Dive

One of the most interesting findings from the study is that male hummingbirds appear to control the sound produced during their dives.

By adjusting their flight speed and the angle of their tail feathers, males can influence the pitch and intensity of the sound.

This suggests the sound itself may function as an important signal during courtship.

In many bird species, elaborate displays evolve because females prefer certain traits. In the case of Costa’s hummingbirds, the sound produced during the dive may help females evaluate potential mates.

A Remarkable Combination of Flight and Sound

The courtship dives of hummingbirds represent an extraordinary combination of aerodynamics, feather structure, and behavior.

Rather than relying solely on vocal communication, hummingbirds use the movement of air across their feathers to produce sound.

This discovery highlights how specialized hummingbird anatomy has become through evolution. Feathers that originally evolved for flight have also become tools for communication.

For anyone observing hummingbirds in the wild, these dive displays are among the most dramatic behaviors in the bird world.

Research Credit

Read the original paper

Clark, C. J., & Mistick, E. A. (2018)
Tail-feather aeroelastic flutter produces the dive sound of male Costa’s hummingbirds.
Proceedings of the Royal Society B: Biological Sciences

Frequently Asked Questions

Scientific studies often reveal new details about hummingbird courtship displays. Here are some common questions about these remarkable behaviors.

Most of the sound heard during hummingbird dive displays is not produced by the voice. Instead, it comes from air moving across specialized tail feathers.
Many hummingbird species perform aerial courtship displays, but this study focused on Costa’s hummingbirds (Calypte costae).
The sounds likely function as courtship signals that help attract females.
During dive displays, hummingbirds can reach extremely high speeds as they descend toward the ground.
Yes. Some birds produce sounds using their feathers during flight or courtship displays, though hummingbirds are among the most dramatic examples.