How do storms affect the birds?

Written by Jack Sanders
Thursday, 15 September 2011 10:21

How did our birds handle Irene? Probably a lot better than we did.

A number of people have expressed concern about the tropical storm and whether it harmed — or at least affected — the local bird population.

For instance, Janet Crawford of Ridgefield wondered about American Goldfinch nests.

“I had discovered only a few weeks ago that they nest in August — after having observed one pulling nesting material from an old piece of sailing line I had hanging off my deck, and then looking it up online — so I’m concerned they may have had nestlings or fledglings when the storm hit,” she wrote.

“When I was awakened by the sound of a tree falling about 5:30 on the morning of the storm, I saw a pair of soaked and bedraggled-looking goldfinches (a male and a female) clinging to the screen of my window, but unfortunately they flew away before I could get a picture.  Anyway, I haven’t been able to find anything online yet about how the goldfinches fared, and I thought it might make an interesting column.”

First off, birds are well adapted to dealing with the kind of weather Irene offered, which was basically strong winds and heavy rain. Their feathers are oil-coated, and shed most of the moisture, and birds have the ability to tightly hold their feathers to their bodies to prevent “leaks.” We saw birds at our feeder the Sunday of Irene, chowing down as it if were just another summer rain.

As for wind, few creatures are more aerodynamic in design than birds. Songbirds should be able to deal with strong winds. During the height of storms, many will hunker down in the sheltering part of a tree, lock their claws to the bark, and point their bodies in the direction from which the wind is coming and let the blasts slide past. Birds that like cavities are even better protected.

But storms present other problems, some of them localized.

Janet’s concern was nesting and it is quite possible that very heavy rain or local gusts — even the “micro-bursts” we heard about in connection with this storm — could have damaged or destroyed nests. While many species are still taking care of nests into August (they produce more than one brood a season), by Irene’s arrival, the goldfinches may have been among the last species that still had nestlings.

Goldfinches have adapted to late-summer nesting — instead of spring and early summer — to take advantage of two things: the down of thistle and other late-summer seeds such as milkweed, which they use to line their nests, and the accompanying seeds of the thistles, which are bountiful this time of year, with which to feed their broods. (Goldfinches are among the few local songbirds that do not feed their offspring insects.)

Could Irene have destroyed a nest? Sure. And so could some of the lively thunderstorms that appear in any of the warm months. Bird nests vary in quality. Some goldfinches or robins are better than other goldfinches or robins at nest-building. And any of them — especially first-time builders — can make construction mistakes that could weaken the nest and make it susceptible to collapse.

Of course, any time a tree falls in a storm, nests or shelters may go with it. Cavity nesters and dwellers like owls and woodpeckers could lose their homes. (However, in the woods, a fallen tree may also create new habitats for other creatures, including birds like wrens.)

Big storms are particularly dangerous for migrating birds. The migration season has already begun and there is no telling how Irene affected migrants, particularly from the far north, that may have run into its winds and rain, especially over the ocean.

Storms may also drive pelagic birds to the shores. These species normally patrol open ocean, but may come to land; for instance, Red Phalaropes were seen near Saybrook the Sunday of the storm. Migrants that normally pass us by overhead might also drop to earth to see refuge. Both possibilities excite avid birders.

Incidentally, a particularly devastating kind of weather for birds is hailstorms. Audubon ornithologist Dr. Stephen W. Kress reports that in 1953, two hailstorms in Alberta, Canada, killed more than 148,000 waterfowl, and that a 30-minute hailstorm in New Mexico killed 1,000 Lesser Sand Hill Cranes.

On their way

Speaking of migrants, our Ruby-throated Hummingbirds have hit the ethereal road, which is typical for our neck of the woods. They not only survived Irene, but were regular visitors to the feeder while the storm was going on, and hung around a week before deciding it was time to go. The angle of the light, not the nature of the weather, is thought to trigger their desire to head south.

Coming up

Guided Bird Walks, Saturdays, Sept. 17, 24, Oct. 8 and 15, from 7 to 9 a.m., free, Audubon Greenwich, 613 Riversville Road, meet in the main parking area, 203-869-5272 x239 greenwich.audubon.org.

Birding with Luke Tiller: 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 Meadow 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.

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] gmail.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877. 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.