Whose nest is that?

OK, so you have a birdhouse in your yard and there is a new nest in there, but what kind of bird is building it? I have had a number of inquiries lately asking me that question. Sometimes the birdhouse is situated where you can’t easily see the birds going in and out. Well, here is how you can figure out what you have in your birdhouse.

First, let’s briefly talk about a couple unique bird nests that you won’t find in a birdhouse. If the nest is in a wreath on your front door, or in a light fixture or a potted plant, the bird is almost certainly a house finch. Once the babies are born the nest will be ringed with bird fecal material making is not so clean to look at.

If you have a bulky football sized mess of hay, grass, etc. in your barbeque grill or on a shelf in your garage the culprit is a Carolina Wren. If you have a mud nest plastered under your high deck, you probably have a barn swallow. There is a great example in the rafters near the entrance to the Village Green Mall.

A Barn Swallow rests on her nest at Village Green Mall

Photo by Don Hazel

Now, if you placed a bluebird nest box in your yard and someone is building in there, here are some clues to see what bird you have. A bluebird nest is very neat, and almost always comprised of fine grass or pine needles. There will be no fecal matter in a bluebird nest because the parents carry away the neat little white fecal sacs for disposal far from the nest. If the nest looks like a bluebird nest but has white feathers lining the nest cup, you might have a tree swallow. They almost always add a few feathers to their nest. If you have tree swallows mount another bluebird box nearby. Bluebirds and tree swallows make good neighbors.

Several other local birds also like bluebird nest boxes. If the hole in your bluebird box is no larger than 1 ½ inches (as it should be) then you won’t have a problem with starlings but another non-native invasive pest, the English sparrow or house sparrow can be a problem. Their nest is messy, and almost always has litter such as plastic or paper in it. Throw them out! The outside rafters at the Village Green Mall are home to about 2 million house sparrows.

If your nest box has a several inch layer of moss below the nest you have either Carolina chickadees or a tufted titmouse. Both birds often line their moss nest with animal fur. Until recently I wondered how they found animal hair. But now I know. The groundhog that lives under the rocks at my neighbor’s house was recently out munching on clover in the backyard and riding on the groundhog’s back was a tufted titmouse feverously pecking away and gathering hair. The groundhog just continued eating and didn’t seem to notice.

A birdhouse full of pencil sized sticks is the sign of a house wren. In fact, these wrens will sometimes fill up every birdhouse in your yard, hoping to attract a female to one of them.

If there is no nest cup in the nest in the birdhouse you might have a nest of mice; look for mouse droppings. And if you find acorns in the mass of materials suspect a flying squirrel. Just one last note of caution…more than one person has had a pants wetting moment when they opened a birdhouse to look face to face with a nest of wasps or worse yet…a snake. Enjoy nature but be careful when checking to see what bird is living in your birdhouse.