UW News

April 27, 2023

Video: Tiny, fierce hummingbirds are also an evolutionary delight for UW, Burke researcher

UW News

Many of us are familiar with the hummingbirds that visit feeders, plants and gardens around us. But these small creatures are unusual in the ways they push the limits of biology, says Alejandro Rico-Guevara, UW assistant professor biology and curator of ornithology at the Burke Museum. He and his students study hummingbirds and other birds that drink nectar. 

“I think what really caught my attention is their personality – how they can be so fierce and so bold despite being so tiny,” said Rico-Guevara.

Alejo Rico-Guevara head shot.

Alejandro Rico-Guevara / UW News

Some of the smallest of all bird species are hummingbirds, and they are unique in the way they fly. They produce “lift” with the forward and backward motion of their wings, enabling them to hover in place for long periods of time, something no other bird can do. A giant hummingbird beats its wings around 10-15 times a second while some bee hummingbirds beat their wings over 100 times a second during hovering displays, using an incredible amount of energy. Hummingbirds have tiny legs and perch when they can, but their speedy metabolism requires them to visit flowers thousands of times and eat 1-3 times their weight daily in floral nectar. These pollinators also eat spiders, a good source of protein. To rest, they are one of few bird species that go into a sleep-like state called “torpor,” in which their metabolic functions slow to a minimum; while active, their heart beats around 600-1200 times a minute.

A hand holds a thimble sized 3D printed hummingbird head with a curved beak.

Rico-Guevara holds a 3D printed hummingbird head he uses to demonstrate beak shapes.

Hummingbirds have evolved so that they are well matched to the flowers they feed from. Their beaks can be long or short, curved down or even tilted slightly upwards to make them efficient at accessing nectar from specific blooms, and, perhaps, useful in fighting. They have become fast and nimble to out-maneuver other animals and insects for nectar, and hovering allows them to access the openings of hard-to-reach flowers.

Hummingbirds are fiercely protective of their food and will chase other birds away from flowers. They fly in front of each other and vocalize to scare each other off. Some hummingbirds will use their claws or bill to poke each other or pluck feathers. They’ve even been known to peck larger birds like falcons or crows, inspiring Aztecs to use hummingbirds as a warrior symbol. During breeding season, males court females with flashy displays of chirping, singing and aerobatics. Hummingbirds can make sounds with their tails and wings and learn new songs throughout their lives.

“It’s a circus,” said Rico-Guevara. “Their behavior is extremely rich.”

Advances in high-speed photography and lenses have made it possible to see bird activity that wasn’t possible a decade ago. Rico-Guevara has used slow-motion video to document the way that hummingbirds gather and swallow nectar, using a long, split tongue that flattens and springs open when it touches liquid, filling with nectar. His newest research describes how space inside the bill fills with nectar as the tongue is wrung out; then the tongue base rakes the nectar as it retracts. Pumping action through the flexible bill helps move the nectar towards the throat. These discoveries reveal a set of coordinated movements that are different and far more complex than what was previously believed – that hummingbirds drank by moving liquid through their tongues or bills using capillary action, much the way liquid will naturally move up a small glass tube.

“It’s all really complicated, and it’s happening up to 20 times a second,” said Rico-Guevara.

“It’s way more intricate than is known for any other bird.”

For more information, contact Alejandro Rico-Guevara / colibri@uw.edu