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Birds' Nests
Nature Bulletin No. 541-A October 26, 1974
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
BIRDS' NESTS
A bird is not taught how to build a nest. When it builds its first one, it
has never even seen a nest built. So far as is known, each kind makes its
own style of nest and does as good a job the first time as it does in later
years. It is guided by instinct as ii each had a sort of built-in blueprint.
While the design for each species remains the same, similar materials
may be substituted. For example, a house wren sometimes uses hairpins
in place of slender twigs; and the crested flycatcher, which habitually
builds a piece of castoff snake skin into its nest, may substitute a
cellophane cigar wrapper.
A nest with eggs or young is a critical time in the life history of a bird.
Losses are heavy. They fall victim to storms, accidents, or any of a long
list of predatory birds, mammals and snakes. As protection against
enemies, nests on the ground, such as those of the meadow lark and the
bobwhite quail, are hidden in the grass. Many, perhaps most, of our
songbirds build nests above ground in brier patches, thorny thickets and
tangles of vines. These are so well concealed that we seldom realize
how many of these summer neighbors we have had until the leaves fall
in autumn and expose them to view.
Our Swallow Cliff forest preserve is named for a colony of bank
swallows which formerly honeycombed a steep bank near U. S. 45 and
Illinois Route 83. Their burrows, often several feet deep, end in nests of
straw, grass and rootlets, lined with feathers.
The chimney swift, once a "hollow tree" swift, has moved into man's
buildings and nests deep down inside of unused chimneys. The nest is a
shallow basket of twigs cemented together with gluey saliva. Because
the swift cannot take off from the ground, dead twigs are snapped off
and grabbed on the fly. After the saliva has dried, this framework is
rigid and strong; but prolonged rain can soften it and spill the eggs or
young. The nests of a cliff-dwelling relative in the Orient, made entirely
of saliva, are collected and marketed, either dried or canned, for the
famous bird's nest soup.
The barn swallow plasters cup-shaped mud nests, lined with chicken
feathers, inside of barns or under bridges. Pellets of wet mud are
pressed into place and reinforced with blades of dead grass. With the
exception of eagles and certain hawks it is one of the few birds that uses
the same nest more than one year. Under bridges we also find the
phoebe's nest of mud, plant fibers and hair, camouflaged with an outer
layer of moss. The tiny hummingbird saddles a small branch with a cup
of fine plant cotton the size of a walnut shell. Cobwebs are used to bind
it fast and attach a covering of lichens. The wood pewee builds a
similar nest, somewhat larger, also disguised with lichens to look like a
knot on a limb.
Among our local birds, nests vary enormously -- some simple, some
complex. The nighthawk merely broods its eggs on barren fields, gravel
beaches or flat gravel roofs in towns and cities. The irresponsible
female cowbird drops an egg here and there in other birds ' nests and
takes no part in the care and rearing of her young. On the other extreme,
the Baltimore oriole weaves an elaborate deep pouch of string, yarn,
grasses, hair and fiber hung at the tip of a swaying branch on some large
tree.
As a rule, the she-bird does all the planning and building.
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Update: June 2012
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