Each May I receive letters and calls about birdhouse building or purchase. Spring migrants have arrived and people hope to encourage them to nest in their yards.
³We have a pair of bluebirds sitting on a clothesline in our backyard,² one correspondent wrote. ³What kind of birdhouse will get them to stay?²
Unfortunately the answer to that question is: almost certainly none. Even if these concerned bird watchers rushed to their local garden store, bought an appropriate nesting box, and set it out in their yard immediately, the bluebirds would rarely use it that year. They would prefer a weathered structure without the human scent necessarily associated with a newly placed house.
Now is the time to build or buy appropriate boxes for cavity nesting birds and to locate them for possible occupancy later this spring. It will be too late in April or May to set out birdhouses.
Nest boxes are simple to make and there are few rules to follow. Their construction is a perfect parent-child activity. Use untreated 3/4 inch lumber. Make the roof extend well out over the entrance hole. Provide additional small holes for ventilation and drainage. Hinge a front or side wall so that it will bend out for cleaning and for quick peeks at the birds in their nest. If you shop for birdhouses, look for these features also.
House size is related to the species you hope to attract. The following dimensions are for interior width, length, height, and hole diameter, all in inches; and placement height in feet. Chickadee: 4 x 4 x 9, 1 1/8, 5-15. Nuthatch, titmouse, bluebird, downy woodpecker: 4 x 4 x 12, 1 1/2, 5-10. Hairy and red-bellied woodpeckers: 6 x 6 x 14, 2, 8-20. Flicker: 7 x 7 x 18, 2 1/2, 10-20. Screech-owl and kestrel: 9 x 9 x 18, 3, 12-20. Wood duck and hooded merganser: 12 x 12 x 24, 4, 5-20. Barn owl: 12 x 36 x 16, 7, 15-30.
Of course locating houses appropriately is important. There is, for example, little possibility that a barn owl box in an urban or suburban setting would attract the desired occupants. Normally this species nests in barns near extensive open fields. (However, strange things do happen. Barn owls once nested in Yankee Stadium.)
About a quarter of our local breeding birds are cavity nesters. In earlier times these birds found homes in hollow trees, but such sites are becoming less available as dead and dying trees are removed from yards and parks and as the ubiquitous starling takes over the few remaining holes. Nest boxes then provide an admirable substitute. They have made a big difference in the welfare of many native species. In particular bluebirds and wood ducks have made spectacular comebacks. Since the 1960s when observers worried about their disappearance from this region, the numbers of both species have tripled. For the recovery of bluebirds special credit is due to birders like Tom Burke of Grand Island who mount and monitor hundreds of nest boxes on bluebird trails. Hunting groups deserve similar recognition for placing and maintaining wood duck boxes.
Some of you will wish to learn more about bird houses. A respected friend, Scott Shalaway, has written a delightful little pamphlet called ³A Guide to Bird Homes.² As anticipated, I learned much from it and recommend it. (If you don¹t find the booklet in local garden stores, call 1-800-879-2473.)
Finally, you can purchase inexpensive bluebird houses for $10 from the Erie County Soil and Water Conservation District office in East Aurora. For more information call them at 652-8480.