Bluebird Nest Boxes
In the late 1800s, European Starlings and House Sparrows were introduced from Europe to the U. S. Both species aggressively competed with Eastern Bluebirds for nest cavities; and by the late 1880s, bluebird populations plummeted. Since the late 1960s, thanks in large part to bluebird enthusiasts who mount and monitor nest boxes, the populations have slowly increased.
Long-time bluebird hosts have gained some school-of-hard-knocks knowledge about bluebird nest-cavity success:Picture

  • Use sturdy, well-built nest boxes, preferably of cedar (for durability), easily opened (for monitoring and maintenance), with a 1 ½” hole, unpainted, minus perches. (For nest box specifications and building plans, see the North American Bluebird Society Web site, here.) 
  • For nest box sites, choose rural, open grassland with nearby high perches, like utility wires.
  • Choose locations void of large house-sparrow populations.
  • Mount boxes on poles, not on trees or fence posts (which serve as ladders for predators), with openings facing southeastward.
  • Mow area near boxes. Bluebirds abandon boxes in high weeds.
  • Mount multiple boxes at least 75 yards apart.
  • Use predator guards, either structures or greased poles, to avoid creating snake/raccoon lunch boxes.
  • Monitor boxes weekly, eliminating house-sparrow nests, ants, wasps, and vacated nests.
  • Leave boxes up year around. Bluebirds travel south only if forced by inclement weather or food shortages. So if berry crops—sumac, poison ivy, dogwood, bittersweet, red cedar, hollies, pokeberry—and the weather hold, bluebirds winter over and use nest boxes as winter roosts.

Hats off to dedicated folks who have brought bluebirds back from the realm of the threatened.