 |
| Osprey nest on floodlights - photo courtesy Sharon Milligan To read previous articles click on the blue title |
Birds are such opportunists. A Morning Dove with a bad case of wanderlust made the news recently. Seems the female built her house of sticks and straw on the frame of a large truck, just over the right front tire. The truck makes daily deliveries in an urban area. The dove was well into incubation duties when discovered by the truck driver, who has assumed the heavy burden of safeguarding her and her potential family for at least another ten days, or until some wildlife agency moves her to safer digs. Meanwhile, he is driving his rig as if he were, literally, sitting on eggs.
There are a number of cases on record of birds nesting in what could be called mobile homes. Here, a few years ago, a Carolina Wren was discovered on a nest in the glove compartment of an open jeep-like vehicle. Rather than move the nest, the rightful owner of the vehicle continued to use it on jaunts to the grocery store, etc., all the while the wren continued to incubate, and eventually fledged a couple of youngsters.
In Starkville, a House Sparrow was found nesting in a moving sign. A Northern Rough-winged Swallow nested on the buttress of a steamboat that makes daily trips across the Tennessee River -- the parent birds followed the boat to feed the young. The Barn Swallow is also reported to indulge in the same nest-site idiosyncrasy. Moving nest sites are unique and probably not too practical, but the idea does point up that for some birds, any place they lay their eggs is home.
The use of man-made sites has become so customary that we tend to forget, for example, that bluebirds have a natural proclivity for tree cavities and old woodpecker poles, as do Wood Ducks, Eastern Screech-Owls and numerous other cavity-nesters for which we now provide high-standard, species-specific housing. Loons are ever nesting on man-made floating islands on northern lakes.
Not all man-made nest sites are intended for avian use. Bridges, for example. A number of species eschew more natural sites in favor of the girders and buttressing of bridges. It's been a booming success for the Rock Dove and any number of swallows. Locally, one can see Cliff Swallows using smaller, low bridges over water, and Barn Swallows sallying out from the concrete overpasses of the interstate highways.
One of our greatest opportunists is the Chimney Swift, one of the very few birds to be influenced favorably by man. Before it discovered chimneys (especially chimneys), air shafts, silos, barns and attics, its housing market consisted of hollow trees.
While it once nested exclusively on cliffs and high ledges, the endangered Peregrine Falcon is adapting to skyscrapers looming over the traffic roar in some of our most popular eastern cities. The American Kestrel, our smallest falcon, will take a window ledge or a cranny behind the crumbling fascia of an old building.
For taking advantage of what's available, the Osprey may be a champ, using duck blinds, fishing shacks, storage tanks, aerials, cranes, billboards, chimneys, windmills, fences, channel buoys and utility poles.
The Mallard (a duck) was found nesting in the rain gutter of a four-story building. Nighthawks are adapting to flat gravel roofs. So, too, are several species of terns (with only marginal success). Barn Owls, with a built-in bias for more natural cavities, do nest in barns -- also steeples, silos, old wells, mine shafts and duck blinds.
And certain wrens are notoriously inventive, using cans, barrels, discarded clothing, flower pots, mailboxes and shoes.
When opportunity presents itself, birds make few distinctions between what is man-made and what is bird-made; certain species regularly use the abandoned natural nests of other birds. Those that use old woodpecker holes are too numerous to list. But old hawk and crow nests are frequently reused by such diverse species as the Canada Goose, American Black Duck, Great Horned Owl, Barred Owl and Broad-winged Hawk. (It takes pair of Broad-winged Hawks three weeks to build a nest from scratch).
Smaller species like the Morning Dove, Common Ground Dove and the cuckoos, none of which is capable of building anything other than a bare-bones platform of twigs, will often refurbish the old nest of another more masterly builder, such as the Northern Cardinal and the Red-winged Blackbird.
Not all birds play by such loose rules of opportunity. Some make their own. The Cattle Egret will pilfer nesting material from its neighbor. The Long-eared Owl may usurp the active nest of another species. There are records of nest-sharing, apparently without mayhem. ... Northern Cardinals and Song Sparrows used the same nest simultaneously, and both successfully raised young. Hooded Mergansers and Wood Ducks have done likewise. So have two female Wood Ducks.
The recyclers, larger birds whose nests were originally major construction jobs, are opportunists of a different ilk. They make a few repairs and do a little spring cleaning-maintenance procedures that make the nest viable for another year, or many many years. Leading that group is the Bald Eagle, whose nest may eventually topple from its own weight. Others that may recycle nests include the Double-crested Cormorant, Anhinga, Yellow-crowned Night-Heron, Mississippi Kite, Red-shouldered Hawk and Red-tailed Hawk.
Smaller birds build a new nest each year, and often a new nest for a second nesting in the same season. What industry goes on in the trees and bushes!
This article was first published in May 1994
