2015 April – SURVIVING & THRIVING IN THE HEAT – Part I

cont…

claudia-kestrel-takes-bath

Birds have some advantages over mammals when dealing with heat. The average bird has a body temperature generally higher than mammals, between 105-107 degrees Fahrenheit. They lack sweat glands, but will open-mouth breathe faster, fluttering their neck muscles, causing moisture to evaporate and create a cooling effect on the body.

They will hunt and forage early in the day, seek shade at midday, and raise their feathers and wings away from their body to dissipate heat.

Unfeathered legs and feet give off excess heat. Leg arteries dilate, carrying more blood to the lower extremities. The heat from the warm blood radiates out and away from the bird.

Water will cool a bird’s legs four times faster than air. You can often see birds bathing frequently during the summer and sometimes just standing in water, be it a bird bath, water bowl, river, stream or puddle.

Vultures excrete liquid waste products down their legs (“urohydrosis”) cooling them by evaporation, and then circulating the cooled blood back through the body.

Young nestling birds cannot regulate their body temperature for 2-3 weeks after hatching. The parent birds can be observed standing in a “shading position” with wings slightly away from their body, dissipating their own body heat while at the same time shading their young for hours on end.

Birds of prey often soar at higher altitudes on the hottest days on thermals of cooler air.

Birds with lighter-colored plumage may turn their lightest parts toward the sun so more heat is reflected away from the body.

Next month in Part 2, we will explore the survival adaptations of mammals and reptiles of our desert Southwest.

References and further reading: desertusa.com * desertmuseum.org * Audubon.org * birding.about.com

April New Year’s Resolution reminder – Consider xeriscaping your decorative garden and yard with drought-tolerant native plants, and flowers or bushes that are natural deterrents to bugs. Help monarch butterfly migration by planting milkweed. Keep bird baths clean.

MAKE IT PERSONAL AND BE PART OF THE SOLUTION!

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