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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #155191
Title: MONITORING DOUBLE-CRESTED CORMORANTS ON A PRIOR NEED TO ASSESS A NATIONAL MANAGEMENT PLAN

Author
item Radomski, Andrew
item Freeman, Donald

Submitted to: Midwest Fish and Wildlife Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2003
Publication Date: 12/7/2003
Citation: Radomski, A.A., Freeman, D.W. 2003. Monitoring double-crested cormorants on a prior need to assess a national management plan [abstract]. In: Midwest Fish and Wildlife Conference. 43:4.

Interpretive Summary:

Technical Abstract: Monitoring double-crested cormorants- an a priori need to assess a national management plan. Andrew A. Radomski and Don Freeman, USDA, Agricultural Research Service, H.K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR Increasing numbers of Double-crested Cormorants (Phalacrocorax auritus) at commercial aquaculture production facilities have resulted in biological, economical, and social conflicts. This is one of the arguments made by the U.S. Fish and Wildlife Service for the creation of a National Management Plan for this species. However, only a few states census cormorants. This may lead to inaccurate assessments of an implemented plan. Therefore, the USDA-ARS has initiated and conducted aerial surveys by fixed-wing aircraft to monitor and quantify the wintering cormorant numbers from 1999-2003. Observations were conducted during the last 3 hours of sunlight and encompassed the primary catfish production areas in Arkansas. Aerial counts were validated with ground observations the following morning at specific roosts for accuracy. A minimum of 16,000 cormorants was observed during each survey, with the exception of early January 2000 and 2001. Cormorant numbers peaked (>26,000) in early February 2001 and a total of 12 to 15 night roost sites were monitored during 1999-2003. Cormorants roosted in bald cypress trees almost exclusively. Some roosts were protected from human disturbances, but some were adjacent to highways or adjacent to high recreational areas. Similarities in numbers of cormorants counted in the evening by aircraft and the following morning by ground observers at the same roost allows for increased confidence that the estimates are reasonably accurate. It is important to monitor cormorants to better understand the population trends, movements during the winter, roost site selection, roosting behavior, and changes that may occur with a national management plan.