Osprey populations throughout the United States suffered serious decline in the 1950s and ’60s, largely due to the effects of the pesticide DDT, potentially harmful chemical compounds known as PCBs and other contaminants. Fortunately, after DDT and most PCB uses were banned in the 1970s, the population of this fish-eating raptor has recovered markedly, even in the face of residual contamination in the environment.
The osprey has had help in soaring again into the public's imagination as an icon of salt and fresh waterways. In the early 1990s, to assist the osprey’s recovery, the Delmarva Ornithological Society—with the support and partnership of the Division of Fish and Wildlife, the Division of Parks and Recreation, the Sussex Bird Club, U.S. Fish and Wildlife Service and U.S. Geological Survey and private entities—took the lead in constructing, installing, repairing and replacing osprey platforms throughout the state.
Additionally, the Natural Heritage and Endangered Species Program since 1970 has conducted surveys to document nest success while and U.S. Geological Survey biologists tested eggs and chicks for contaminants in 2001. Until recently, osprey surveys were concentrated in the Inland Bays and Nanticoke River system, but the entire state of Delaware was surveyed in 2003 and statewide surveys will continue periodically in future years. In 2003, more than 200 nests were surveyed; 119 nests were active, and 76 of those were on nesting platforms. In comparison, the state’s osprey population was estimated in 1975 at only 46 pairs.
Delaware’s osprey population has increased dramatically and may be stabilizing, yet much is still unknown about the species in the state. For example, because the Natural Heritage and Endangered Species program can typically conduct only two to three nest checks per year, exact dates of egg laying, chick flights, nest failure and other key nesting milestones are difficult to pinpoint.
While Fish and Wildlife staff simply cannot monitor all nests throughout the nesting season, the Osprey Nest Monitoring Project allows volunteers to fill in the gaps by monitoring osprey platforms and nests near their home or workplace. All data will be analyzed by Natural Heritage and Endangered Species staff and will add to a better understanding of osprey arrival dates, nest success and other aspects of osprey biology in the state. This knowledge also will enhance the state’s surveys and support conservation decisions for osprey. Data gathered about this majestic bird also can serve as indicators of environmental health. Because ospreys are high on the food chain and eat foods—primarily fish—that accumulate toxins, their status can foretell problems that also may affect humans.
Osprey Nest Volunteer Program
The Natural Heritage and Endangered Species Program has been monitoring the densest concentration of ospreys in the state, the Inland Bay population, since the 1970s. In 2003, when this survey work was expanded to include other portions of the state, approximately 120 nests had eggs or chicks. The number of active nests has probably grown over the years, so a lot of help is needed. Since formal surveys are conducted only twice during breeding season - once to count eggs and once to count chicks - and surveys are done but periodically, volunteers will help fill in the data gaps for a subset of nests.
2008 Update: Ospreys have returned from their wintering grounds in South America and Delaware’s volunteer osprey watchers have returned to monitoring them. Osprey volunteers sign up to watch specific nests (ones that are on public land and/or visible from roads) throughout the season and collect detailed information, such as time of arrival, start of incubation and first flight. Last year volunteers spent over 250 hours observing 33 nests.
The Division of Fish & Wildlife continues to seek volunteers to help monitor osprey nests throughout Delaware. Volunteers are asked to visit their chosen nest(s) at least once every other week from March until the ospreys leave in late summer for their annual migration to South America. Ideally, volunteers should have identified a nest near their home or office, or be willing to drive to one often. Volunteers also should have access to email to report their findings and to receive updates on what’s happening with other nests around the state.
Volunteer osprey monitors will receive an information package including data sheets, maps and other useful information. Please note: This project will not involve repair or construction of nesting platforms. To register for the training or to find out more about volunteering for the Osprey Monitoring Project, please contact Jeremiah Dann, Delaware Division of Fish & Wildlife, at 302-632-1519, or by email Jeremiah.Dann@state.de.us).
