How hot birds have been keeping cool

Written by Jack Sanders
Thursday, 04 August 2011 13:51

The recent hot spell, during which temperatures exceeded 100 degrees on at least one day, affected birds as well as people. Birds, however, can’t flip on the air conditioning.

Birds have no sweat glands but recent research indicates they can perspire through their skin. Perspiration cools the body as the moisture evaporates, a process similar to the workings of an air conditioner. However, birds, like dogs, seem to rely more on panting as a cooling technique. On a very hot day, you will notice many birds with their beaks open as they give off excess heat through the lining of their mouths.

According to research biologist Stephen W. Kress in his book Bird Life, if the brain temperature of a pigeon increases from 107 to 109 degrees, its breathing will more than triple from 46 to 150 times per minute, allowing it to pass three times more air over its mouth lining.

Some birds, such as cormorants, use another heat regulation technique called “gular fluttering.” This is a rapid movement of the throat that causes air to pass over the throat membranes and reduce body temperature. Many baby birds use this technique.

Vultures and storks sometimes employ “urohydrosis”: They pee on their legs. As the urine evaporates, it cools the legs — and the vulture.

In general, many birds are less active when it is very hot. They seek shade and many also seek water — a dip in a puddle, stream or birdbath. They will also hold their feathers close to their bodies, reducing their insulating effect and increasing the radiation of body heat. Some birds will hold out their wings to let the breezes cool them.

Tree thief

Ivan Spangenberg of  Chestnut Hill Road  in Wilton was prompted by the column on bears at the feeder  to report,   “A month or so back, checked our birdhouse to find it wrapped around its support branch as if some animal had lifted it up about three feet and dropped it down the other side.  Now I have a similar ‘attack’ on our recently filled finch feeder  — as if it was lifted up and dropped again down the other side of the branch.

“Both times I had to get a ladder up to untangle the cords. Of course the seed was gone.  Both locations have many branches above making it impossible to swing them up and over by a high wind.

“I’m thinking of possibly a raccoon although we haven’t seen any in several years.”

Ivan is probably right. Raccoons are adept at moving around in trees and at figuring out how to enjoy the bounty of a birdfeeder.

Nest-watcher

Kevin Doyle has been following the nesting cycle of a couple of pairs of Osprey along Long Island Sound and provided the accompanying photo of a parent and two chicks at a nest off Sherwood Island in early July.

He has been to the Sherwood Island site so many times “the other day the female, had I opted to, would have let me walk right up to the nest.  She didn’t spook nor cry out — as though she recognized me.”

Coming up

Jamaica Bay Wildlife Refuge trip with Naturalist Tait Johansson, Saturday, Aug. 6, 10:15 to 4; Bedford Audubon, leave Bylane Farm, 35 Todd Road, Katonah at 9,  This e-mail address is being protected from spambots. You need JavaScript enabled to view it , 914-519-7801, www.bedfordaudubon.org.

Sharon Audubon Festival, nature walks, displays, talks, music, food, more, Saturday and Sunday, Aug. 13 and 14, 9 to 5, Audubon Sharon, (860) 364-0520 or check www.sharon.audubon.org.

Jamaica Bay Wildlife Refuge, with Tait Johansson and Walter Fowler, Saturday, Aug. 30, 8:15 to 2, from Bylane Farm, 35 Todd Road, Katonah, at 7. Bedford Audubon, This e-mail address is being protected from spambots. You need JavaScript enabled to view it , 914-519-7801, www.bedfordaudubon.org.

Birding with Luke Tiller: Saturday Aug. 6: Westport Shorebird Hotspots, 8:30 a.m.; Sunday, Aug. 28: Westport Shorebirds, 1 p.m.; Saturday, Sept. 17: Trout Brook Valley, Easton, 7:30 a.m.; Sunday, Sept. 25: Westport Warblers, 7:30 a.m.; Saturday, Oct. 8: Allen’s Meadows and Secret Hotspots in Wilton, 7:30 a.m.;  Saturday, Oct. 29: Sparrow Big, 7:30 a.m.;  $10 each; To register visit www.sunrisebirding.com/walks.htm.

Norwalk Island Birdwatching Cruises, aboard the C.J. Toth Quest ferry, with guide, Sunday,  Aug. 7,  Wednesday, Aug. 10, 7:30 to 10:30, Adults $22, kids $12, Norwalk Seaport Association, from ferry dock at Water and Washington Streets, South Norwalk, seaport.org, 203-838-9444.

Birds in Their Habitat art exhibition and sale, featuring bird carver Floyd Scholz, Sept. 23 to 25, Connecticut Audubon, 2325 Burr Street, Fairfield,   203-259-6305, ext 407.

HawkWatch Weekend and Green Bazaar, live birds of prey shows, kids activities,  food, eco-friendly businesses, more, Oct. 1 and 2, 11 to 5, Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 x239 greenwich.audubon.org.

Copyright 2011 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] yahoo.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877; or call 203-438-1183, extension BIRD (2473), and leave a message with your report, spelling your first and last names and telling us your town. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.