We all find bird nests from time to
time and some of us even construct them at summer camp. I found the nest at the right one
day as I walked deep inside a soybean field. Obviously a recent storm had blown it there.
The nest is 2.5 inches across (6.5 cm), is covered on the outside with lichens, and most of the nest's body is composed of thin
grass fibers, and what looks like fuzzy padding from a hunter's falling-apart chair left
in the woods! At the left you can see a close-up of some of the lichens adorning the nest's
exterior. These lichens were put there by the bird building the nest. They help waterproof
the nest and camouflage it. When I picked up the nest the first two questions that popped
into my mind were:
- What makes the lichens stick to the nest's
exterior?
- Why does the nest feel so "spongy"
After a little poking at the nest I knew: spider webs.
Gently I pulled apart one corner of the nest and saw
what is shown at the right. White, silky strands of spider web stretched across the tear.
You know that most spider webs are sticky so that insects caught in them have a hard time
escaping. That sticky stuff makes a fantastic glue for keeping certain bird nests
together.
WHO BUILT THAT NEST?
Let me tell you how I figured out what kind of bird had built this nest. My detective
work was fun, and it's exactly the kind of fun you can have, too. I began my deductive
process by paying attention to these details:
- nest size
- nest structure
- nest composition
- by knowing what birds are present locally
SIZE: The size, 2.5 inches (6.5 cm)
across is pretty small, so obviously it hadn't been built by anything like a hawk, crow,
or even something as large as an American Robin or a Mockingbird. My first guess -- my
first hypothesis -- was that it was a warbler's nest, for warblers are small birds and we
have several warbler species here.
STRUCTURE: Here are the main kinds of
bird nests classified according to structure:
- Scrapes -- shallow depressions scratched
into the ground or leaves, such as the oystercatcher's
- Platform nests -- platforms built in
tree tops or on shallow water, such as the hawk's
- Cup nests -- the most common type, built
by most songbirds, shaped like a cup
- Adherent nests -- a kind of cup nest,
typically mud, plastered to a building wall or stone ledge; Barn Swallows make them
- Pensile nests -- a cup nest suspended
from the forks of a tree branch, such as vireos build
- Pendulous nests -- bag-like nests
suspended from the tips of branches, as built by orioles
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My nest was shaped like a cup and I could see from the fact that no lichens had been
stuck to the nest's lower sides that the nest probably had been built in the fork of a
tree branch. Figuring out that I had a "cup nest" therefore eliminated the
vireos, which are also common, small birds here, for they build "pensile nests."
Here was more evidence that my hypothesis that the nest had been built by a warbler was
correct.
NEST COMPOSITION: I knew that the lichens
covering the nest commonly grow on the bark of forest trees, so that was more evidence
that the nest was a warbler's, because most of our warblers live in the forest. The fuzzy
chair stuffing also supported this idea, because hunters sometimes leave old kitchen
chairs in the woods to sit on as they wait for their deer!
BY KNOWING WHAT SPECIES ARE PRESENT: Well,
I knew that there were a lot of warblers here...
However, I still didn't know which warbler had built the nest, and in fact I
wasn't really sure that the nest had been built by a warbler in the first place.
GOOGLE TO THE RESCUE!
At this point I Googled the nest. In other words, I went to the Google search
engine and when the word box came up I typed in these words: bird nest spider web
lichen. That's not very grammatical, but search engines look for keywords, not good
grammar.
Google did not come up with a warbler. It came up with several pages on the
Ruby-crowned Kinglet, which is an even smaller woodland bird than the warblers I'd been
thinking about. The problem with Ruby-crowned Kinglets, however, is that they are not
found in my area during the summer, and I found this new-looking nest in the summer!
Nonetheless, mention of the Ruby-crowned Kinglet was important, for we do have
a small woodland bird here during the summer which belongs to the same family as
the kinglets, and that's the Blue-gray Gnatcatcher. And usually birds in the same family
build rather similar nests.
Now I re-Googled my nest, this time using Google's "Images" feature, using
the key words blue-gray gnatcatcher nest. And up came pictures of nests looking
as much like my nest as they possibly could. I also Googled warbler nest and saw
that most warbler nests are not covered with lichens and aren't nearly as neat and
roundish as my gnatcatcher nest.
Therefore: Blue-gray Gnatcather!
Nest-Googling is something you should remember the next time you find a bird nest. Why
not try it now, using my key words, or some you make up? Here:
So, the thing to remember when you want to identify a nest is, first, pay
attention to the four characteristics outlined above and then Google the nest to
confirm or reject your suspicion. |