Don’t Forget the Birds – So How Do Those Hummingbirds Survive?
Island Voices, January 2025

Don’t Forget the Birds – So How Do Those Hummingbirds Survive?

By Ed Swan

Ed Swan was a master ornithologist with an incredible depth of knowledge and a generous enthusiasm to share it. He inspired many Islanders to learn about birds, and was a regular columnist for The Loop. This article appeared in the January 17, 2007 issue.

During this long cold spell, many may be wondering what birds do to survive the cold. Birds utilize a number of adaptations that enable them to regulate their heat and make it through inclement weather. Birds use both physical and behavioral mechanisms to minimize heat loss.

Behaviorally, many species deploy a variety of tactics for keeping warmer. The main areas of heat loss involve their legs and bills, since they lack feathers for insulation. Birds often stand with one leg tucked up into the feathers, cutting the exposed area in half. Flocks of shorebirds may often be seen resting with their bills inserted into their feathers. One combination includes covering the bill and sitting low to cover both legs. A warmer feeding strategy employed by juncos consists of holding their breast feathers down to cover their legs as they scoot along the ground looking for seeds. In addition, pretty much all bird species might be seen at one time or another puffing themselves up into a ball to hold in heat.

Finally, birds take advantage of environmental sources of energy such as the sun to help them out. They orientate their bodies to expose the maximum area to the sun. Many possess dark feathers or skin pigments towards their rump that they turn to the sun for better heat absorption.

Birds have a number of physical adaptations to help them out. Some reduce blood flow to and from their legs to lower their temperature and avoid bringing in cold blood to the center of their body. Others have the veins and arteries touching within their legs, so that the warm blood coming out from the body’s center heats up the cool blood coming in.

Our hummingbirds use another method to make it through. They seek sheltered areas to rest and become less active in order to to expose themselves less to the cold and use less energy. They may also induce torpor. Torpor reduces their energy requirements. They drop their internal temperature, breathing, and heart rates. Active birds stay at around 40°C, birds in torpor drop down to 9-12°C. In one study, an Anna’s Hummingbird suspended its breathing for up to 5 minutes at a time.

Torpor has its price; birds are unable to react quickly to predatory and other threats, taking several minutes to revive. They also require an immediate easy, energy boost of food.

Ed’s article continues with a round-up of local bird sightings, specific to the time of his writing, Jan. 2007. To read in full, go to the Loop Archives, and select v. 4 #2. The article is on p. 7.

January 8, 2025

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ed swan