AVIS-IBIS

Birds of Indian Subcontinent

Autumn Migrations of Peregrine Falcons on Assateague Island, 1970-71

Publication Type:Journal Article
Year of Publication:1972
Authors:F. Ward, P, Berry, RB
Journal:The Journal of Wildlife Management
Volume:36
Issue:2
Date Published:1972
ISBN Number:0022541X
Keywords:Falco, Falco peregrinus, Falconidae
Abstract:In 1970 and 1971, the autumn migrations of peregrine falcons (Falco peregrinus tundrius) were studied on Assateague Island in Maryland and Virginia. During a 22-day observation period in 1970, 68 peregrines were sighted and 28 were trapped, but 5 were recaptures of falcons banded earlier in the survey. In 1971, 120 peregrines were sighted in 16 days; 35 were banded and 10 were recaptured, some several times. Of the falcons banded, immature birds comprised 87 percent and 89 percent, respectively, of the samples in 1970 and 1971. Of the falcons sighted that could be positively identified, 85 percent in 1970 and 91 percent in 1971 were immatures. These data, when compared with other records kept intermittently since 1939, suggest that the abundance of peregrine falcons in 1970 and 1971 was probably not different from that of recent years. Age ratios of the sighted and trapped birds, reported to be the best indicators of the reproductive success of the population, corresponded favorably with all previous records. However, comparisons of peregrine sightings in 1970 and 1971 with those recorded by a single observer between 1939 and 1947 suggest that a significant population reduction occurred after 1947.
URL:http://www.jstor.org/stable/3799079
Short Title:The Journal of Wildlife Management
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