As I’ve gotten to know birds better over the years, I’ve come
to appreciate the wide variety of nests they build, but especially the artistry
that some of them exhibit in their construction process. I’m a slow learner, mostly
because bird nests are not easy to find—and that’s exactly what their aim is:
to build a child-raising lair that places their vulnerable offspring in a
well-disguised place. If nobody catches them in the act, that’s just dandy.
There are many bird enthusiasts who are far more accomplished
than I am at locating bird nests. Maybe I tend to respect their privacy a
little too much, since seldom have I located a nest in use. When fall arrives, however,
I am able to spot a few nests much more easily, after the trees have dropped
their leaves. Now and then, during the season, a nest will be blown down by a
storm and I can examine the fine handy work up close. It is a special treat,
and I always preserve the nest.
Some birds, such as the phoebe and the Carolina wren, prefer
to build under the cover of manmade structures, so their nests may be rather
obvious. And some, such as bluebirds and chickadees, are happy to move into
nesting boxes, so I can locate their nests and later examine them, after they
raise their babies. But most birds tend to be secretive about the location of
their nests.
Building a nest requires a variable amount of time and energy
investment—dependent on how elaborate they decide to go. Woodpeckers put in
many hours excavating holes in trees. Their type of nesting carpentry requires
a huge investment.
Nests, however, are not absolutely necessary for raising
young. Some species drop their eggs on the ground in an obscure location. The ancestors
of birds—the ferocious dinosaurs—laid their eggs directly on the ground. The
birds, descended from the dinosaurs, grew smaller and became more vulnerable.
They learned how to fly. That allowed them to look for more lofty perches for
their lodges.
The whippoorwill and turkey are local birds that still nests
directly on the ground. The whippoorwill can get away with it, because their
coloring is so cryptic that you could almost step on a brooding mom and not see
her. I say almost, because she will suddenly flush, just before your foot plops
down.
There is also a wide diversity in the way birds go about
selecting a nest site. Most nest building falls to the prospective mom. At the
least, it’s her choice as to location of the nest. She will spend some time,
when her first hormonal pangs set in, shopping around for a satisfactory home
site. There is also a learning curve that applies. Mom may not do all that well
with her first nest—either in its location or its robustness—but her next nest
will probably be better. That can be a reason why the offspring of some species
hang around to help mom and dad with subsequent broods: to learn some of the
finer points of nest building and baby raising. This is a fine example of
cultural learning, as opposed to instinctive actions.
More on nests next time…
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