Small Bird Detering Barn Swallows

Asked September 14, 2020, 11:28 AM EDT

We have always had barn swallows in the floor joists of the high bay of our old wood barn. This year they came in the Spring as usual and had their first crop, lots of cheep cheep and droppings. Then a small gray bird (no bigger than a swallow but more round and puffy) arrived building a nest high under the eves of the adjacent building. This bird was not at all skittish like a sparrow and spent time in the barn and sitting on the basketball hoop on the barn door. In two experiences I walked close enough to it that I was afraid of being pecked and it never flinched. I saw mostly the female but for a week or two think I saw a slightly more colorful male. I never saw it bothering the barn swallows but after it arrived we found white egg fragments and never saw anymore young being raised. We have from time to time seen and heard the swallows on the wire where they usually perch but no more in the barn. The droppings continued but less and different in character with no more cheep cheep. Could there be a new predator on Barn Swallows or their young?

Washtenaw County Michigan

3 Responses

Hello,

First off the new bird you described matches quite well for an Eastern Phoebe. They frequently nest int he rafters or edges of human made structures. They are a gray birds with a yellow to white belly, and they typically pump their tales when they are perched. A pleasant bird to have a around and an insectivore like Barn Swallows that eat primarily flying insects.

I reviewed the literature on Phoebes and did not note any records of aggressive behaviors towards swallows, however they are an under studied species and do have somewhat similar diets and foraging habits, so their is a chance the Phoebes chased them off. It is also somewhat likely that a known predator of Barn Swallows may have attacked the nest. Those are many and include hawks, squirrels racoon, snakes, bull frogs, grackles, crows, and commonly domestic cats. It's important to keep domestic cats indoors as outdoor cats kill billions of birds annually. There are many predators, but there are also cases where Barn Swallows may decide not to have a second clutch dependent on the adults health, weather and other unknown variables.

Given the Phoebe is a bird protected under the migratory bird treaty, and that there is no direct evidence they drove off your barn swallows, I would leave them alone and see what happens next year. Phoebe have less of a chance of returning to the same site as they often pick new sites for nests each year. You can, however, protect your birds from predators by placing a fencing or some other structure in a perimeter around the area where your swallows nest to stop squirrels or snakes from climbing up to their nest.

Hope that helps,

Best,

Elliot Nelson

Thanks Elliot; The squirrel Idea is interesting. The top floor of the barn is a major walnut storage area for our squirrels. They are also well established. There is a big knot hole in the floor within a foot or so of the nest that the birds seemed to abandoned. I could make metal shields for the floor joists on which the swallow nests are anchored but squirrels are hard to deter. Next year I will watch closer and try to get a picture of the gray bird if it returns.