IUCN 08/17/2021 – Least Concern (LC), Population Trend Increasing.

U.S. and Canada Conservation Status: Critically imperiled in 3/66 states and provinces (AR, IN, MS). Imperiled in 11/66 states and provinces (SK, YT, AZ, DC, MO, MS, NJ, NM, OK, RI, WV). Vulnerable in 19/66 states and provinces. Apparently secure in 34/66 states and provinces. Secure in 10/66 states and provinces.

The data used in this figure are listed above. These data were compiled from NatureServe and the U.S. Fish and Wildlife Service.

Not listed. They are protected under the Migratory Bird Treaty Act (MBTA).

Alaska, Forested Canada and the Great Lakes region to Chile and Argentina.

Boreal forests, mountain valleys, temperate coasts, lakes, rivers, subtropical coasts, and desert salt-flat lagoons. Requires a fish supply with shallow waters, open nest sites, and an ice-free season for breeding.

Along with many other raptors, Osprey were likely negatively impacted by the use of DDT, with DDT negatively impacting nest success by causing reduced eggshell thickness. Following the DDT ban in the 1970s, Osprey migration trends were already rebounding according to long term counts at Hawk Mountain Sanctuary. This suggests other factors may have been negatively impacting Osprey populations, such as shooting. Hawk Mountain observed increases until the mid-1990s when the count plateaued and began to decline again, leading up to the 2019 RPI analysis, where recent count averages have dipped back down to count averages observed in the mid-1960s, which were DDT era lows. Quaker Ridge, a count site in Southwest Connecticut observed consistent declines from when the site started collected data in 2002 to 2015 when the counts averaged out to a stable plateau for until 2019. At Hawk Cliff Hawkwatch, which sees an average of 138 Osprey each fall, Osprey counts began in 2002. Osprey declines began in 2013 and were observed through 2018.

These maps summarize the latest RPI trend analyses for count sites throughout North America.

Find the interactive version of the Christmas Bird Count (CBC) maps here.

BBS: BBS data deficient for this species so trends should be interpreted with considerable caution. Most states and provinces show increases excepting Ontario and Idaho for the survey time span from 1966 to 2019.

Further research is needed to determine why Osprey are declining in some regions. Declines may be localized and should be assessed on a regional and seasonal basis. Some possible contributors could be loss of habitat, human-Osprey conflict, electrocution, environmental contaminants, and competition with Bald Eagles, particularly in inland nesting areas. Recent increases in wildfire frequency and intensity may impact Western populations, though there is no consistent evidence across data sets to show declines have occurred in the West. Osprey can be susceptible to mercury and other contaminants and this impact should be further assessed where declines are observed.

Osprey rely on healthy lakes, streams and wetlands. Although billions of dollars have been allocated to wetland protection and restoration, wetland acreage continues to decline in quality and abundance. In 2004, only 28% of stream and river miles in the United States are considering in “good biological condition”. Global coastal wetlands have lost more than 50% of area in the 1900s, and losses were further accelerated in the last three decades due to aquaculture, urbanization, harbor and navigation channel construction, and sea level rise among other factors (Li et al., 2018). It is predicted that three million birds have been lost in coastal wetland biomes, which include Osprey habitat in the Northeast region. Some research shows regional declines in wetlands due to increased timbering and agricultural runoff. Other areas are impacted by development such as urbanization and aquaculture. Interspecific competition with Bald Eagles is suspected to be a cause of nest abandonment and decreased occupation by Ospreys, particularly near the Great Lakes. Bald Eagle populations have been on the rise (see Raptors on the Rise, Bald Eagle), and they fill similar ecological niches to Ospreys, and are known to steal prey and may exclude Osprey from historical nesting areas. This does not appear to occur in coastal colonies where Osprey groups can fend off intruding eagles.

Although the use of organochlorines in North America have become heavily regulated, the continuing effects of other agrochemicals including pesticides and herbicides on Ospreys have not been satisfactorily explored. Across the continent, eggshell thickness and reproductive success were significantly lower for this species during the popularized use of DDT. One study found that the number of nesting pairs in a Northeastern colony had declined by 31%. Even after the DDT ban of 1972, DDE has continued to persist in the environment and expose wildlife to contamination. The possible ongoing effects of DDE on Osprey should be further explored.

Localized heavy metal poisoning may also impact Osprey population. Of 244 Osprey in the Chesapeake Bay region of Maryland and Virginia tested for blood lead concentration, 62% had detectable lead concentrations. Osprey ingest lead by consuming fish that contain lead from possible contaminants such as legacy lead paint on bridges and other industrial structures, lead acid battery storage facilities, coal-fired power plants, leaded aviation fuel, and lead ammunition and fishing equipment. Consumption of lead can cause Osprey to be more susceptible to other injury or disease, or at higher levels, they can suffer from lead toxicity and mortality (Slabe et al, 2019). Mercury is also a globally ubiquitous highly toxic metal that bioaccumulates in long-lived, top-level predators through food webs. It is particularly of concern in aquatic ecosystems and readily accumulates in fish. High concentrations of mercury can cause neurological symptoms and impairs reproduction by altering behaviors such as nest attendance, decreases reproductive output due to endocrine disruption, and decreases survivorship in young. A 2007 study suggested that Osprey likely access hot spots of mercury contamination in coastal habitats and risk of accumulation is likely tied to localized contamination during migration and on overwintering grounds (see Hopkins et al, 2007). More research is needed on the impacts of mercury contamination on Osprey reproduction success.

Osprey are highly vulnerable to exposure to oil contamination due to their prey base and foraging strategy, more than any other raptor species. Risk of oiling can arise from oil spills, platform failures, discharges from oil boats, and additional risk of exposure can occur when Osprey consume fish contaminated with petroleum-derived products. Oil slicks can reduce hunting success and oil contamination compromises feathers’ structure and flight capacity which can cause inefficient thermoregulation and mortality.

More research should be done effects of now widely used flame retardants such as polybrominated biphenyl ether (PBDE) on reproduction as a result of the increased wildfires. Research has shown Ospreys are contaminated with PBDE in Oregon, Chesapeake Bay, and British Colombia.

Osprey have historically been shot by humans in both the US and in South America where many to overwinter. In Colombia, recoveries of banded Ospreys that have been shot have increased since the 1970s and has been shown to coincide with the development of aquaculture facilities.

Electrocution has become a common threat to nest success in the West, especially Wyoming, (unpublished data from the Teton Raptor Center). In rural Western US, 520 raptors were confirmed to have suffered mortality due to electrocution between 1986-1996 (Harness and Wilson et al, 2001). Vehicular and aircraft collision also cause mortality in Osprey, particularly where human populations are increasing. From 2000 to 2015 in Florida, 23.6% of Ospreys admitted to rehabilitation centers were injured through vehicular collisions.

Literature Cited

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Slabe, V. A., J. T. Anderson, J. Cooper, B. Brown, P. Ortiz, J. Buchweitz, D. McRuer, and T. Katzner. (2019). Lead in piscivorous raptors during breeding season in the Chesapeake Bay Region of Maryland and Virginia, USA. Environmental Toxicology and Chemistry, 38(4), 862–871. https://doi.org/10.1002/etc.4376

United States Environmental Protection Agency (EPA). 2006. Wadeable Streams Assessment. Office of Research and Development, Office of Water, Washington, DC. https://www.epa.gov/sites/default/files/2014-10/documents/2007_5_16_streamsurvey_wsa_assessment_may2007.pdf

USFWS. 2014. Species Status Assessment for Species Osprey (Pandion haliaetus).

U.S. Fish and Wildlife Service. 2021. Birds of Conservation Concern 2021. United States Department of the Interior, U.S. Fish and Wildlife Service, Migratory Birds, Falls Church, Virginia. http://www.fws.gov/birds/management/ managed-species/birds-of-conservation-concern.php

Wilsey, C., Taylor, L., Bateman, B., Jensen, C., Michel, N., Panjabi, A., & Langham, G. (2019). Climate policy action needed to reduce vulnerability of conservation‐Reliant Grassland Birds in North America. Conservation Science and Practice, 1(4). https://doi.org/10.1111/csp2.21

Partners in Flight, Vanishing Habitats. https://partnersinflight.org/vanishing-habitats/

Learn more about this species natural history at All About Birds or at Hawk Mountain’s website.