U.S. Fish & Wildlife Service

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Division of  Migratory Bird Management

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Atlantic Flyway Sea Duck Survey

• Known offshore (greater than 700 m) sea duck concentration areas are not covered during this survey. Research is currently being conducted to identify important offshore concentration areas and to understand when these areas are used by sea ducks.

• Additionally, this survey does not cover major wintering concentrations of common and king eiders north of Cape Breton, nor does it cover the Great Lakes.

• No similar survey currently exists for the Pacific Coast.

Anthony Roberts
Wildlife Biologist, Atlantic Flyway
US Fish and Wildlife Service
11510 American Holly Drive, Room 212
Laurel, MD 20708-4038, USA
voice mail: (301) 497-5852
fax:  (301) 497-5885

During the 1980's, restrictive harvest regulations linked to declines in mid-continent duck populations and restrictions on black duck harvest led to a shift in hunting pressure to lesser-utilized species, such as sea ducks. Concern among Atlantic coast waterfowl biologists about this increase in pressure on sea ducks led to a variety of surveys indifferent areas being conducted at different times, using a variety of techniques that were not compatible.

Existing breeding population surveys for North American waterfowl do not cover the core ranges of about half of North American sea duck species. Many species of North American sea ducks breed across vast Arctic regions that are difficult and costly to survey. Winter waterfowl surveys such as the Mid-winter Waterfowl Survey typically do not cover near shore or offshore coastal habitats used by sea ducks. The Atlantic Flyway Sea Duck Survey was established in 1991 to record sea duck numbers using near shore (within 700 m of shore) habitats from Cape Breton, Nova Scotia to Jacksonville, Florida.

During this survey, two-person aerial crews count all sea ducks observed within 250 m of either side of the aircraft. The number of all species of waterfowl observed within the boundaries of the transect are recorded. Mixed flocks are recorded by percent species occurring within the flocks. Large flocks of sea ducks that occurred off the transect are noted by species and number. Hunting parties are also noted.

The survey is flown as a continuous transect 400 m (3 mile) offshore, parallel to the shore, and including all major rivers, bays, sounds, and gulfs. The continuous transect is sub-divided into approximately 16-km (10-nautical mile) segments. Aircraft are flown at approximately 60 m and 90-100 knots. The survey is flown in late January or early February.

Densities are calculated on a per-square-mile and per-square-kilometer basis by state or province and country.

A pilot survey was conducted in 1990, and operational surveys have been conducted from 1991 to 2002, except 1993 and 1996. This survey was discontinued in 2003 because of budget shortfalls in the Division of Migratory Bird Management. Efforts are currently underway by the Division, working with the Sea Duck Joint Venture and the Atlantic Flyway, to evaluate alternative survey methodologies for winter sea ducks. In particular, methods to survey aggregated, mobile populations in near and offshore waters and to evaluate detection rates are currently under consideration.

Databases of segment, state/province, and country-level sea duck counts and state/province and country-level sea duck densities are maintained by the FWS/USGS Migratory Bird Data Center.


Field Name Field Description
Year Survey year
Country Country in which survey segment is located
Statprov State or province in which survey segment is located
Segment Survey segment number
Species Species code
Offline Counts made off the survey segment
Count Counts made on the survey segment
Flown Yes = 1, No = 0

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