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Raptors: Surveys and Population Monitoring
Raptors: Surveys and Population Monitoring

Evaluating Osprey Nest Abundance, Distribution and Productivity in Casco Bay

Ospreys are one of the quintessential wildlife bioindicators. Knowledge of Osprey nest abundance and productivity were instrumental in our ability to detect, and eventually ban, the pesticide DDT regarded as one of the most devastating compounds released into our environment. Besides Ospreys' well-demonstrated role in monitoring spatial, geographic, and temporal trends of contaminants in our environment, Ospreys are also effective monitors of ecological health. That is, Osprey nest distribution and productivity (the number of chicks surviving per nest) are responsive to environmental changes, such as those in the underlying foodweb relied upon by wildlife and humans.

What We Studied

What We Studied

Minimal efforts have been undertaken to survey Osprey populations in Maine. This data gap limits our ability to assess the current status of the population or to detect changes in the future. The detection of such changes often provides the initiative to investigate potential causes. For Ospreys, observed changes in populations could relate to factors affecting individuals on their breeding grounds, tropical wintering grounds, or anywhere in between (i.e., during migration).

With support from the Casco Bay Estuary Partnership, BRI and collaborators at the Maine Department of Inland Fisheries and Wildlife have just conducted a three-year (2011-2013) survey of the Osprey population in Casco Bay, Maine. This effort, gathered through aerial surveys, aims to estimate and document the abundance, distribution, and productivity of the Osprey population residing in Casco Bay. This three-year measure will be compared to data collected during a previous three-year survey effort conducted in the 1980s to provide insights on long-term changes in the Osprey population residing in Casco Bay.

 

Additional Information

2011 season survey, full report:

DeSorbo, C. R., R. Gray, and I. Johnson. 2013. Osprey abundance, nest distribution, and productivity in Casco Bay, 2011. Report BRI 2013-08 submitted to The Casco Bay Estuary Partnership, Portland, Maine. Biodiversity Research Institute, Gorham, Maine. 21 pp.

2012 season survey, summary:

DeSorbo, C. R., R. Gray, and I. Johnson. 2013. Osprey nest abundance, distribution and productivity in Casco Bay: 2012. Report BRI 2013-09 submitted to The Casco Bay Estuary Partnership, Portland, Maine. Biodiversity Research Institute, Gorham, Maine, 7 pp.

Article in Connections, Muskie School of Public Health, University of Southern Maine:

DeSorbo, C. R. 2012. Surveying Osprey in Casco Bay. Connections: Spring 2012, Muskie School of Public Service, University of Southern Maine, Portland, Maine. May 2012.

 
Photo Credits: An adult Osprey in flight. Photo Credit Sharon Fiedler. A banded adult Osprey in flight. This individual was banded by BRI as a nestling in Penobscot Bay, Maine in 2007 and has been observed in multiple years since. Photo Credit Sharon Fiedler.
Biodiversity Research Institute