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Airdate: Apr 25, 2000
Scientist: Doug Altshuler

Hummingbirds: Physiology

Hummingbirds: Physiology
A scientist who studies hummingbirds in Peru has found that different hummingbirds' physiques are matched to their style of foraging for nectar.

In southeastern Peru, there's a road that starts up high in the peaks of the Andes and travels downward, deep into the Amazon rain forest. Along this road are some of the best places in the world to study hummingbirds. I'm Jim Metzner, and this is the Pulse of the Planet, presented by DuPont.
Doug Altshuler is a biologist at the University of Texas at Austin. He studies hummingbirds in and around Manu National Park in Peru.
"We're most interested in the links between physiology, or the way a hummingbird can perform flight, how it flies and what its behaviors are. And hummingbirds all forage on nectar, flower nectar, which is a very rich resource, but they do it in many different ways. Some hummingbirds are territorialists and they will defend flowers vigorously from all other invaders, where other hummingbirds engage in a foraging style that we call trap lining, where they go between many widely dispersed or distant resources which don't have a lot of nectar but have a very rich nectar. And in between, there are lots of other things. There are hummingbirds that we call marauders, because they invade whatever flower they want and kick other hummingbirds away."
Altshuler's theory is that physical variations in different types of hummingbirds determine how they gather food. The trap lining hummingbirds are lightweight, with large wings, so that they can forage over a wide area easily. They also have long bills to get nectar out of flowers with especially lengthy tubes, flowers other hummingbirds can't reach into.
"Whereas a lot of the territorial hummingbirds are going to be very heavy because they want to have a lot of mass so they can push another hummingbird around and they also often will have very short wings, so that they can be aerodynamic and zippy little guys that can chase others."
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