BLUEBIRDS DAZZLE CAPE CODDERS (3/30/00)

Bluebirds, bluebirds! If there's one bird that catches the fancy of birdwatchers, it's the Eastern bluebird! The brightest spot in late winter is often the return of this beloved bird. Although some bluebirds make it safely through the winter, many of them migrate south. However, come late February they return and are ready to nest, although not in the abundance in Massachusetts as further to the south.

As many of you know, bluebird populations all over the East suffered serious decline, starting in the 60's, as a result of the use of DDT and loss of their nesting habitat. Application of DDT not only killed many of the insects on which bluebirds depend, it also poisoned the birds themselves. On top of that, housing developments and shopping centers began to consume the rural areas, including old orchards, where bluebirds nested in holes in fence posts and in the fruit trees, to say nothing of the adverse effects that non-native English sparrows and starlings have had by usurping favored nesting sites.

Fortunately, through the efforts of the North American Bluebird Society and its members who encouraged homeowners to furnish houses for bluebirds, these beloved birds have made a strong comeback. Thanks go also to the many people all over the East who have established bluebird trails. Such trails consist of a series of bluebird houses placed at least 100 yards apart. On the Cape, numerous golf courses and cemeteries provide these beneficial trails.

One reason that nesting along golf courses is successful for bluebirds is explained by the findings made over the past few years at Mass. Audubon's Arcadia Wildlife Sanctuary which has been looking at the effect of various mowing regimes on the foraging behavior of nesting bluebirds. The preliminary results indicate that bluebirds prefer open areas with scattered trees, where the ground is not covered with tall grass but with grass that is less than three inches tall.

The study also found that putting out perches in the grassy areas increased bluebirds' use of these areas. Bluebirds are also partial to gardens and sparsely vegetated sites. There are some indications that good foraging areas close to nesting boxes increases fledgling success.

If you want to try to attract bluebirds to nest in your yard, now is the time to prepare for them. You can either buy or build your own nest box, but the dimensions must be specific to bluebird tastes. Although the general size of a box is 5” x 5” on the base, and 8” high, it is important that the hole be placed 6” above the floor and be 1 1/2” high and 1 1/4” wide. Never put a perch on the front of the house, as this will allow predators to intimidate or injure the bluebirds. Leave the birdhouse a natural color and place it away from trees and shrubs and about 5 feet off the ground. Attaching it to a metal post that you grease with anything that will make it slippery will help prevent raccoons and snakes from gaining access. If you haven’t attracted bluebirds or tree swallows by late spring, close your box up or take it down, but do not let English sparrows, vicious bluebird predators, take over any box.

Bluebirds often have two, occasionally three, broods a year, laying from three to six eggs per clutch. After the female lays the eggs, she begins to incubate, a process which requires 13 to 14 days. The young usually hatch simultaneously and leave the nest 16 to 18 days later.

A dandy book, a must for anyone who wants to provide nestboxes and natural habitats is The Backyard Birdhouse Book, written by Rene and Christyna Laubach and published by Storey Books. This book covers all the essentials of placing nestboxes in the proper habitat, box designs, birdbox “dont’s,” monitoring of nesting progress, cleaning of boxes, and detailed profiles of cavity-nesting birds.

As many local residents have found, a birdbath is a big attraction for bluebirds. This winter I have heard from many readers who have been thrilled to find bluebirds at their baths, including this one: “Seven Bluebirds in heated birdbath on Sunday Jan. 23rd in Centerville.  Never have seen Bluebird in thirty years on Cape Cod much less that many at one time.”

If you do have a box and don’t attract bluebirds, one consolation may be that a beautiful blue and green tree swallow may find it and call it home. I’d love to hear about your efforts, whether successful or not.