Code

CCBTR-04-16

Publication Date

2004

Abstract

Virginia’s first full-time systematic seabird watch was conducted 9 November through 20 December 2003. The project was a collaborative effort among The Center for Conservation Biology of the College of William and Mary, the Virginia Coast Reserve of The Nature Conservancy, the Virginia Department of Mines, Minerals and Energy, the Virginia Department of Environmental Quality, the United States Coast Guard, and the Eastern Shore of Virginia National Wildlife Refuge. The watch site was the 191 foot tall Cape Charles Lighthouse, located 2 kilometers north of the southern tip of Smith Island, an Atlantic coastal barrier island in Northampton County on Virginia’s Eastern Shore. Two full-time technicians, Elizabeth Rogan and Jason Wade, manned the site 32 out of a possible 42 days, logging 184.25 observation hours. They documented the passage of 75,138 birds of 57 species of which 71,298 were seabirds, that is, species that utilize the ocean as a migration corridor and/or as a primary foraging resource. Birds which fall within this designation include Red-throated and Common loons, Horned and Red-necked grebes, Northern Gannet, Great and Doublecrested cormorants, 17 duck species, Parasitic and Pomarine jaegers, 5 gull and 5 tern species, Razorbill and Dovekie. The additional 3,840 birds included songbirds, marsh dwelling waterfowl (ducks, geese, swans, and herons), and shorebirds. Watch data, including metrological conditions such as wind speed and direction, ambient air temperature, percent cloud cover, visibility, relative humidity, and barometric pressure were recorded hourly following a prescribed protocol. Meteorological information was obtained with a Davis Vantage Pro Wireless Weather station. Also recorded were minutes of observation, species flight distance from shore, and flight altitude above the water surface. Reference markers demarcating distances up to 2 kilometers were placed off shore to aid in determining flight distance from shore. Visual observations were made with Leica Televid 20-60 power spotting scopes and Leica 10 X 42 Trinovid binoculars. Boat transportation for the technicians to and from Smith Island was provided daily by James Clark, a local contractor. Six volunteers participated in the 2003 project including Virginia residents John Spahr of Waynesboro, Elisa Enders of Portsmouth, Robert Eggleston of Harrisonburg, and Alaina Thomas of Cape Charles. Fletcher Smith from Pecatonica, Illinois, and Jethro Runco from Newton, Kansas, both seasonal ornithologists, also assisted. A total of 75,138 birds of 57 species was recorded during 184.25 hours of observation, a rate of 408 birds/hour. Sea ducks accounted for 49 % (34,687) of the total 71,298 seabirds counted. Dark-winged scoter species comprised 85 % (29,590) of the sea duck total and 42 % of the total number of seabirds. Northern Gannets constituted 25 % of the total seabirds with 18,100. Gull species (Laughing, Herring, Ring-billed, Great Black-backed, and Bonaparte’s) made up 10% of the total with 7150 birds and terns (Caspian, Royal, Common, and Forster’s) comprised another 5 %. Loons, primarily Red-throated, and cormorants represented 5 % and 4 % respectively of the seabirds total. The highest count-day totals for all species were recorded 16 November (13,877 birds) and 1 (10,192 birds) and 2 (14,931 birds) December. The peak movement of sea ducks occurred 22 November - 4 December, with a maximum count of 2,927 25 November. A significant movement of Northern Gannets took place 16 November and 1-4 December, with a count period high of 4564 on 2 December. Staff also conducted a parallel hawk count 9-30 November. Approximately, 100 hours were logged during 17 observation days. 137 diurnal raptors of 9 species were recorded of which 34 % (46) were Black Vultures, 24 % (33) were Northern Harriers, 14 % (20) were Bald Eagles and 9 % (12) were Sharp-shinned Hawks. Additionally, 1 Osprey, 6 Turkey Vultures, 2 Cooper’s Hawks, 6 Red-tailed Hawks, 6 American Kestrels, and 5 unidentified raptors were noted.

Species

Seabirds

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