Janesville48°

Birds build nests in all shapes, sizes

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D.S. Pledger
March 29, 2014

When I'm hiking around in the early spring before the foliage comes out again, I like to keep an eye out for old bird nests.

They come in all sizes, shapes, are made up of a multitude of materials and can be seen high in the tree tops or literally on the ground.

Sometimes they'll surprise you. There are the remains of a catbird nest in the fire bush by our house. We had seen the bird around last summer but didn't realize it was living just 10 feet from the shed.

Likewise, there is a cardinal nest we found hidden in the grapevines over the dog run but never noticed the birds that used it.

All bird nests do basically what those cardboard cartons that you buy at the grocery store do—protect eggs. The list of materials they use to do this is almost endless. Mud, stones, feathers, grass, twigs, roots, leaves, shed snakeskins, fur, spiderwebs and shells, as well as an equally amazing number of man-made materials such as dryer lint and fishing line show the ingenuity of birds in building their chick incubators.

Some of the more resourceful avian architects choose man-made “nests” such as mail boxes, porch lights or a discarded hat if it's inverted. In one case a bird nested in the pocket of a pair of overalls that had been left on the wash line overnight. Others are opportunists, taking over nests made by other birds or simply doing a makeover of an old one.

A few birds, notably the wren, construct a number of nests. The male toils to build three or four different stick piles while his mate sits passively nearby, watching him before selecting the one she wants to lay her eggs in. Does she want to see how ambitious her mate is, or does it take several attempts before he gets it right?

Maybe she's just fickle.

Hummingbirds use lichens and moss held together with a little mud to make a nest about the size of a walnut shell, whereas the bald eagle constructs what could more accurately be called an avian playpen for its slow-maturing young. One eagle nest was used continuously for at least three dozen years and was estimated to weigh two tons when a storm finally knocked it down. And if nearly four decades seems like a long time for a nest to be used, one particular stork nest was reportedly in service for almost four centuries.

Plover and woodcock raise their young directly on the ground, although sometimes the depressions they use are lined with soft material to keep the eggs out of the mud and cushion them. The bird might also build up the sides for a bit for camouflage even though the eggs of ground-nesters usually have a highly camouflaged pattern on the shell.

Hanging nests like those of orioles are among the most distinctive and easily recognized. There are nearly 100 species of birds that use this kind of architecture, and while the oriole's is loosely woven, some species in other parts of the world actually sew them together, pushing coarse grass strands into one wall and then pulling them through from the opposite side.

Aquatic birds such as loons and grebes build floating nests that function better on the water than on land. Most are tethered to the bottom in some way, although a few drift around like miniature boats.

Weather conditions can make a big difference in nest placement. Two years ago most of the nesting grounds of our local geese were underwater, so some improvisation was necessary. I'll never forget the sight of a mother honker brooding her eggs 10 feet off the ground in the fork of a silver maple. I wonder how she got her chicks out of it after the flood receded?

D.S. Pledger is an outdoors columnist for The Gazette. Email him at maus16@centurytel.net.



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