Movements of Land-based Birds 
Off the Carolina Coast 
David S. Lee and Kenneth O. Horner 
North Carolina State Museum of Natural Sciences, 
P.O. Box 27647, Raleigh, North Carolina 2761 1 
ABSTRACT . — Although the occurrence of land-based birds at sea 
during migration periods is well known, relatively little information is 
available on the species composition of the flocks detected by radar. 
This paper lists 96 species documented from the offshore waters of 
North and South Carolina, offers evidence for offshore movements by 
groups of birds other than nocturnal migrants, and suggests temporal 
changes in flock composition. 
It is well known that land-based birds regularly occur at sea during 
migration periods, when flocks of birds or individual birds deliberately 
or accidentally take oceanic routes. Various authors have demonstrated 
(through personal observation and radar studies) that offshore movement 
of nocturnal migrants occurs in the North Atlantic on a regular basis 
(Scholander 1955; Drury and Keith 1962; Williams et al. 1977: Davis 
1978; McClintock et al. 1978; Richardson 1978, 1980; Larkin et al. 1979; 
Cherry et al. 1985; Williams 1985). Nisbet (1970) and others have 
proposed that a long, over-water flight crossing the Atlantic directly to 
South America is a normal and deliberate route for some species (e.g., 
Blackpoll Warbler). Although fall movements over the western North 
Atlantic Ocean have been documented, there is relatively little in- 
formation on the species composition of the migrant clouds detected. 
Furthermore, individual records of land-based birds found at sea 
generally have gone unrecorded and unreported. Here we identify some 
of the offshore migrants, present evidence for offshore movements by 
groups of birds other than nocturnal migrants, and suggest temporal 
changes in flock composition. 
Our sightings of land-based birds were for the most part recorded 
incidental to studies of seabirds during the 10-year period from 1975 to 
1986. They were made primarily 10 to 55 miles (16-88 km) off the North 
Carolina coast between 30° and 35°N. Sightings were made without 
optical aids, but identifications were often made with binoculars. It 
should be emphasized that many land-based birds observed at sea could 
not be specifically identified because of distance, boat movement, 
atypical flight postures resulting from strong winds, and other adverse 
conditions. We estimate that 55% of the land-based birds seen in flight 
disappeared from the field of vision before they could be identified. 
Brimleyana No. 15:1 1 1-121, January 1989 
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