ALWAYS IN SEASON: Barn swallow numbers boom
The barn swallow population has exploded at our place west of Gilby, N.D. We’ve had barn swallows each of the 16 years we’ve lived there, and sometimes cliff swallows, too, but never this many, proving that “barn swallows now sometimes nest in larger colonies than probably occurred in natural settings.”
That assertion is made in the monograph on barn swallows in the series “Birds of North America.”
Early in the summer, I counted 11 nests on three buildings at our place, including the house. From these nests, at least three dozen fledglings emerged.
Barn swallows are hard to count, since they move so adeptly through the air, but I’m confident the number of fledglings can’t be many fewer than 40.
Two nests each produced five young swallows, and three others produced four. That gets us to 22 young swallows — with six nests uncounted. I know that one nest failed. That still leaves only 14 more swallows in five nests to reach the three dozen mark.
And that’s not the end of it.
At least three of the swallow families have nested again, and one pair built a new nest. At first, I thought they might only be practicing, but there are half a dozen eggs in the nest now.
So the population explosion isn’t finished.
Another remarkable feature this year is how near the nests are to each other. Two pairs have nests within 8 feet of each other, and one pair — the late nesters — built right around the corner from another active nest.
The nests vary greatly in their placement. Most are under the eaves, but one pair nested on the vent below the second floor roofline. That’s close to 20 feet above the ground. One pair squeezed a nest into a narrow space between the roof and a supporting beam on the east wall of my book house, which once was a granary. Still another pair put their nest on a downspout, just where it angles away from the eave.
The common feature of all these locations is a support for the foundation of the nest. Once secured, a barn swallow nest can last a long time. One of the nests on the house has five layers. The space between the overhang and the top of the nest is getting tight. I wonder if the birds will fit into it next year.
The swallow pair that lost their nest made a critical error. They placed it too close to the level of the deck. One of the cats leaped at it, missing the swallows but knocking down the nest.
I admit taking down one nest. It was located directly over the door that leads from the deck to the kitchen, and I didn’t want to take any chances with a bird spoiling my grilling.
The swallows are strongly territorial. They try to drive me away from their nests with loud chirping and daring dashes. I can feel the wind beneath their wings as they whip across my head. This is a little unnerving.
Otherwise, the swallows are welcome. They are beautiful and entertaining. Their flying ability is inspiring.
Plus, they eat enormous amounts of mosquitoes.
So I consider our place especially favored to have so many swallows.
In general, the swallow family is a sociable bunch. Cliff and bank swallows form enormous colonies. Purple martins are well known for their colonialism, as well.
This has not been so much the case with barn swallows, however. Before European settlement, barn swallows nested in caves. That makes it a pretty good likelihood that there weren’t any swallows in the Red River Valley in those days.
Since humans have built across the land, however, barn swallows have adapted. In fact, they’ve almost completely converted to nesting on manmade structures, and they’ve begun nesting in bigger groups.
This is a change I’ve observed in my own lifetime, and in fact, in my time at Gilby.
The swallow colony at our place appears to consist of paired adults and some unattached birds. Such “nest helpers” are relatively common in the bird world, occurring with such species as eagles and crows, among others.
In the case of swallows, these hatchlings from last year may help raise a new generation. Ornithologists speculate that some may be opportunists hoping to benefit from the breakup of a mated pair.
These helpers add to the population explosion at a swallow colony.
Jacobs is a retired publisher of the Herald. Reach him at firstname.lastname@example.org.