The town's nest box program at the Drake Landing off-leash dog park has once again attracted nesting pairs of tree swallows.

Parks Manager Christa Michailuck says the boxes were introduced to the area as part of the town's biological control program for flying insects.

The program was launched several years ago after the town began receiving complaints about the number of mosquitoes buzzing around the off-leash park, and mosquito larvae checks determined that the adjacent storm pond was not the source of the problem. That led them to believe that mosquito larvae was flourishing on surface water on private property or in nearby ditches, but it also left them with limited options to try to control the pests.

That sparked the idea to try to attract insect-eating birds to the area.

"Tree swallows are aerial insect eaters, so they catch their insects while flying through the air," Michailuck explains. "They're not just a mosquito-eater, but mosquitoes would be included in their diet. And that was our intent of the nest box program was to decrease mosquito populations around the off-leash park for the enjoyment of the off-leash park users."

Currently, 12 of the 20 boxes are occupied by tree swallows, with wrens and house sparrows occupying some of the others. Although they added six more boxes last year, Michailuck says the swallow nest box occupancy rate remains basically the same this year compared to previous years.

"I think we were surprised to get so many tree swallows the very first year that we put the boxes up," she says. "And we estimate we've fledged about 50 young tree swallows from the entire program each year."

Local volunteers play a big role in the town's tree swallow nest box program, Michailuck says. They've helped with everything from assembling boxes to making rounds and reporting their findings to the town.

"Once the birds arrive, they make their rounds and they check on the boxes to see which boxes are being occupied and if there's any other species that are occupying the boxes," she says. "They'll do an egg count and they'll do a hatchling count throughout the nesting season."

Once the baby birds are a certain number of days old, she says the volunteers know to stay away from the boxes in order to not interfere with fledging.

Michailuck says eggs in the swallow nest boxes should be due to hatch any day now.

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