According to veteran bluebirder Dick Tuttle, adult Tree Swallows consume 2000 insects and feed 6000 insects to their young over the ~45 day nesting period. That means that each nestbox family consumes more than 300,000 insects. Since 90% of hunting pf their hunting takes place below 39 feet, they are making a real dent in human pestering insect populations.
For people who want to attract a lot of Tree Swallows in habitat that is not idea for bluebirds (e.g., poorly drain3d fields with tall vegetation, Dick Tuttle recommends a grid system, with boxes spaced 22-25 YARDS apart. (Tree Swallows will nest within 65 feet or each other). Entrances can face east to south.
Tuttle describes the set up in the NABS Bluebird Journal, Winter 2006-2007, pages 18-19. Here is how you would lay out a nice, neat 5x5 grid with 25 nestboxes.
Use a post pounder to install the corner post for the first row. Tie a chalk line to the corner post (the black circle on the diagram).
Unravel the chalk line as you walk 100 yards (the length of a football field) and install a second stake (the red circle on diagram). Tighten the chalk line around the stake.
Return to the corner post, and use the chalk line to guide installation of three more posts 25 and 50 and 75 yards from the corner (If you are alone, it helps to tie loops of chalk line around each post.)
Go to one of the corner stakes, turn a perfect 90 degrees, and walk 100 yards to mark off the second side of your square grid (corner stake is navy in diagram), just like you did in steps 1 - 2. Then mark off the in between posts at 25, 50 and 75 yards, like you did in step 3.
Then either measure or eyeball the remaining spots (gray circles), and install the boxes with wobbling predator baffles.
Warning: Passive House Sparrow management has no place in a grid set up, as male HOSP may claim multiple boxes.
I *am* responsible for what *I* do. What I want to know is not how does what we do affect the overall success rate, but rather, how many individual bluebirds and Tree Swallows, including nestlings, will die as a predictable result of what I do. I don't have any reason to believe that they are willing to sacrifice themselves and their babies so that I can achieve my goals for bluebird restoration.
- Paul Kilduff, Bluebird_L, 2007
