Living Inside a Tree Swallow Grid
April 5, 2010
As a young girl, one of the first horror movies I saw was Alfred Hitchcock’s “The Birds”.
I love this movie still and it brings back many fond childhood memories whenever I see it. We have a vacation home on South Bass Island on Lake Erie and the bird populations there are different from those I see at our home in central Ohio. The first nesting season on the island found me installing nest boxes around the yard and sort of unintentionally installing a Tree Swallow Grid on our lot. The lot is mostly open, with a view of the lake across the street; the back yard borders the airport and is very open as well. We built the house with the living area on the second floor and windows abound so the view is fantastic from a birder’s perspective.
The only way to the island is by boat, ferry or airplane. Last spring, friends leaving the ferry dock commented about seeing a large group of birds circling over our house. The ferry docks almost a mile from our house so this gives you an idea of the spectacle that exists in our yard during nesting season.
Tree Swallow Grids installed in central Ohio adhere to more stringent standards than the ones found in our yard on South Bass. Scientific studies indicate that Tree Swallows nest comfortably no closer than 22 yards apart and the standard set-up in central Ohio is 25 yard nest box spacing. In central Ohio, we almost always have a resident pair of Eastern
Bluebirds in a grid, but there are no nesting Eastern Bluebirds on South Bass Island, to my knowledge, to date.
On the first weekend in April, we stayed at our home on South Bass Island on Lake Erie.
On the previous weekend, I had "planted" the nest boxes in anticipation of the Tree
Swallows' return, and this weekend they were back with a vengeance. This year, there are 14 houses in the Tree Swallow grid: 11 bird houses in my yard, two in my neighbor's, and a really big blue house that I sit in while sipping my morning coffee and watch the show from. With nest boxes in the front yard and nest boxes in the back yard, I am smack dab in the middle of it all. Every box had 2 to 4 Tree Swallows on it or flying around it and about 50 more flew overhead circling the area, vying for a spot, and eating whatever insects they found up there I'm sure. Alfred Hitchcock would have been proud.
I also saw a lone male Purple Martin on the back rig on April 3rd. This is a little early for them here in northern Ohio. While perched inside my big blue house, observations with
Purple Martin housing are that European Starlings definitely have an affinity for the horizontal gourds. House Sparrows tend to leave the gourds alone, but are very attracted to standard aluminum rectangular compartments.
Interesting interactions I observed this weekend were a European Starling landing to enter a horizontal gourd on the front rig and a Tree Swallow drove him off. A female
Brown-headed Cowbird landed in the gravel next to a Tree Swallow box and the resident pair pounced on her, accompanied by their raucous warning call. House Sparrows are

easy to catch in the boxes here because the Tree Swallows alert me immediately that there is an avian interloper by changing their call from their happy twitter/chortle to a raucous gutteral alert call. If the House Sparrow (HOSP) hopes to maintain his footing in a box, he likes to plant himself in there and look out, but is reluctant to abandon his real estate as the Tree Swallows swoop and dive in front of it, trying to make him leave. This is the time for the "Paula sneak" and I simply make a circuitous route around the box, pretending not to notice Mr. HOSP while he watches me intently (while in his view). I then sneak up on him from behind, smack my hand over the hole, and he is mine. I had observed a male HOSP checking out 5 different boxes and after I caught this one, there were no more the next day.
While living inside "the grid", I can actually start the day knowing what is going on out there without even looking. When I wake up, I listen for the happy twitter/chortle of the
Tree Swallows and know everything is fine. I hear the distinct "CHEEP" of the HOSP and know I have to set a trap or two before I brew the coffee. I hear the Tree Swallow alarm call and wonder if the neighbors would laugh if they saw me doing the "Paula sneak" in my bathrobe. Spring is finally here!
The spectacle of circling, swooping Tree Swallows around our house will soon be expanded with the return of the Purple Martins that fill our two Purple Martin rigs. They will swoop and circle a bit higher, feeding on flying insects in the higher realms while their smaller cousins eat insects in the lower strata. I expect some visitors at the ferry dock will be pointing and wondering.
Bluely Yours,
Madame WingNut