August 17, 2010
Meet the Ospreys of Cape Cod
by Ian Ives, Director, Mass Audubon’s Long Pasture Wildlife Sanctuary
Ospreys—Pandion Haliaetus—are a raptor found in every continent of the world except Antarctica. The species is well adapted to fishing and can be found anywhere there are safe nest sites and shallow water with abundant fish.
Ospreys found on Cape Cod are migratory, traveling thousands of miles twice a year between here and as far south as Venezuela. They are monogamous, yet pairs separate during their time in South America, reuniting upon their spring arrival to raise young back on the Cape.
Mass Audubon’s Long Pasture and Wellfleet Bay Wildlife Sanctuaries on the Cape have recruited more than 60 volunteer Citizen Scientists to monitor the reproductive activities of Ospreys here. Volunteers “adopt” an Osprey nest site and monitor such notable milestones as the arrival times of mated pairs from their wintering grounds, nest building, breeding, incubation of eggs, feeding and fledging of chicks.
Our goals are to support a robust population of ospreys in the region by cataloguing and mapping nest sites, collecting long term data on reproductive success, comparing our data with other sites in the region and across North America, and presenting conclusions for public awareness and understanding.
Standardized data has been collected over the course of the last three years showing a healthy and robust population on Cape Cod. By the end of the 2009 field season we catalogued and monitored 216 nests, of which 123 were deemed successful (nests that produce young fledglings). No less than 88 percent of the nests we monitored fledged young. This is a very high fledge rate in comparison to published data on other Osprey populations across North America.
For example, only 38 percent were successful in Florida Bay, 63 percent in the Florida Keys and 79 percent in coastal New Jersey. This indicates the Cape has plenty of resources to support Ospreys and room for more young Ospreys looking to establish nest sites.
This field season promises to reveal more surprises and fascinating accounts of this spectacular and endearing bird.