Eastern Bluebird Sialia sialis

Eastern Bluebirds generally inhabit rural areas and farmlands, but they will also take advantage of open glades, beaver meadows, and forest openings created by fire or log­ ging (Conner and Adkisson 1974; DeGraaf et al. 1980; Kiviat 1982). Their primary habitat requirements are the presence ot elevated foraging perches and suitable nest­ ing cavities, either natural or man-made (Pinkowski 1977b). Studies by Pinkowski (1977b, 1979) and Goldman (1975) showed that Eastern Bluebirds usually hunt by drop­ ping to the ground after locating prey from a perch; therefore low vegetation facilitates foraging. their care and the female prepares for Bluebirds are not as easily located as subsequent broods (Thomas 1946; Hart­ many other open-country species, but care­ shorne 1962). Fledgling dates for Vermont ful scanning of fencerows and yards with range from May 21 to August 23. Pinkowski nest boxes often leads to their detection. (1977b) found that predation and inclement Their soft, warbling song does not carry weather were common causes of nesting fail­ long distances. Confirmation is not difficult, ure among bluebirds in Michigan, and that primarily because the species tends to use many pairs succeeded in raising only one nest boxes. In Atlas Project priority blocks, brood. Family groups often stay together 78% of the records were confirmations. The during migration. The peak of fall move­ location of nests accounted for 69% of all ment is during late September to early Oc­ Vermont Atlas Project confirmations; 39% tober. A few individuals may successfully of these nests contained young. Recently winter in southwestern Bennington County fledged young contributed an additional during mild winters. 18% of the confirmations. Early accounts of the birds of Vermont Eastern Bluebirds winter in the central indicate that the Eastern Bluebird was com­ and southern U.S., returning to Vermont in mon throughout the state in the mid to late late March. The female gathers dry grass or 1800s (Thompson 18 S3; Cutting 1884). pine needles for the nest and begins egg lay­ Early in the twentieth century writers de­ ing within a few days of nest completion, scribed the bluebird as a common summer continuing until a full clutch of 3 to 8 blue resident in some areas (Perkins and Howe eggs (usually 4 to S) is laid (Bull 1974). The 1901; Fortner et al. 1933). However, in the average of 19 Vermont clutches is 4-4 eggs. early I900s, as bluebirds lost habitat to re­ Up to 3 clutches are laid in a season (Hamil­ forestation, they also began to experience ton 1943; Thomas 1946; Hartshorne 1962). competition for nest sites from introduced Dates for 24 nests containing eggs in Ver­ House Sparrows and European Starlings. mont range from April 20 to July 29. The Both of these species, being more or less young hatch after an incubation period of sedentary, are able to claim nesting cavities 13 to IS days (Thomas 1946; Hartshorne before bluebirds arrive in the spring, and 1962). Nests with young have been reported the larger starling can easily evict bluebirds on 24 dates between May 15 and August IS from cavities with large enough entrances in Vermont. Nestlings fledge after 17 to 18 (Bent 1949; Zeleny 1976). Pruning and cut­ days, at which time the male takes over ting in orchards and woodlot edges have

238 Species Confirmed as Breeders in Vermont n"

No. of priority blocks in which recorded H' TOTAL 92 (p%) Possible breeding: f4 (, 5% oftota!) Probable breeding: 7 (7% of total) Confirmed breeding: 7I (78% of total)

Physiographic regions in which recorded % of % of species' no. of region's total priority priority priority blocks blocks blocks

Champlain Lowlands 14 45 IS Green Mountains I8 33 20 North Central 42 9 Northeast Highlands 2 I3 East Central I4 74 IS 43' Taconic Mountains '4 88 IS 30 ! Eastern Foothills 22 92 24

also contributed to bluebird decline by de­ priority blocks, followed closely by the East creasing the number of natural cavities (Bent Central region. In the Champlain Lowlands, 1949; Zeleny 1976). During the winter and where competition with introduced species when they first arrive in the spring, many is most severe, bluebirds were located in bluebirds die if ice or snow covers the fruit only 45% of the priority blocks. The areas they depend on for winter food. It may take of lowest bluebird density in Vermont are bluebird populations several years to recover the heavily forested high elevations of the after particularly harsh winters (Forbush Green Mountains and the Northeast High­ 192 9; Bent 1949). lands. The Eastern Bluebird has been on the In Vermont, two Audubon chapters­ National Audubon Society's Blue List since Rutland County and Ascutney Mountain­ 1978. In Vermont, numbers of bluebirds have had active nest box placement and could probably be increased by the place­ monitoring programs. Perhaps as a result of ment and monitoring of additional nest these efforts, the Eastern Foothills and Ta­ boxes in suitable habitat. conic Mountains had the highest concentra­ NANCY L. MARTIN tion of bluebird records in Atlas Project

Eastern Bluebird 239