Osprey

These raptors may be found on nearly every corner of the world, but the Chesapeake region is home to the largest concentration of nesting osprey.

Scientist Rebecca Lazarus with the U.S. Geological Survey Patuxent Wildlife Research Center takes us to Poplar Island, Maryland, to show us how she conducts contamination studies on the local osprey population and to explain why the bird is so important to researchers. Produced by: Steve Droter/Chesapeake Bay Program

Overview

Ospreys are one of the most iconic species in the Chesapeake Bay. While they’re found across the world, the largest concentration of the rapture exists right here in the Chesapeake region. They arrive in the Chesapeake Bay region in early March and remain here through spring and summer, when they migrate southward for the winter in mid-August.

How many ospreys are in the Chesapeake Bay?

Infographic indicating that there are around 20,000 ospreys that breed on the Chesapeake Bay and 100,000 ospreys in the world.
The Chesapeake Bay watershed is home to the largest concentration of breeding ospreys in the world. Banning the chemical DDT, creating man-made nesting sites and reintroducing osprey to areas with high-quality habitat have had a positive impact on osprey populations. (Data provided by the Center for Conservation Biology.)

Estimates from the Center for Conservation Biology place the Bay's current osprey population at eight to 10,000 breeding pairs, with the world population estimated at fewer than 100,000 birds. This is a significant increase from the 1970’s when it was estimated that there were as few as 1,450 breeding pairs. Research from the 1990’s showed an increase in reproduction among breeding pairs, with rates growing from less than 0.8 young produced per active pair in the 1960s to more than 1.2 young produced per active pair in the mid-1980s. Reproduction rates returned to less than one young produced per pair in the late 1980s.

What impacts ospreys?

In the Chesapeake Bay, ospreys are most impacted by habitat loss, access to fish and the release of toxic contaminants into the water. Ospreys live along the tidal portions of the Bay, where they make their nests and hunt for food. Development on shorelines can replace or disrupt this habitat, while low populations of fish can make it difficult for osprey to support their young. Additionally, toxic contaminants make it up the food chain and impact the health and reproduction of ospreys.

Ospreys breeding in the Bay

Historically, the Chesapeake Bay has supported the largest concentration of breeding ospreys in the world. Ospreys are typically monogamous and will mate for life. Breeding pairs have been known to return to the same nest site year after year. Females lay three eggs between mid-April and late May, which incubate for 38 to 42 days. Access to trees or man-made platforms to nest in is crucial for the survival of ospreys, as they need a place to safely keep their eggs from predators. Each summer, you can watch osprey eggs hatch through nesting cams from the Chesapeake Conservancy orChesapeake Bay Foundation.

The recovery of ospreys in the Chesapeake Bay

While the widespread use of toxic pesticides pushed populations of ospreys to an estimated low of 1,450 breeding pairs in the early 1970s, a 1972 ban on the pesticide DDT helped populations recover. By the mid-1990s, an estimated 3,500 breeding pairs were found on the Bay, and breeding was documented on almost half of the Bay's tidal tributaries. Today, an estimated eight to 10,000 breeding pairs live in the Bay.

Restoration efforts have included reintroduction programs, where wildlife biologists release osprey into areas with high quality habitat, as well as the creation of man-made nest sites to counter the loss of trees. Today, many osprey populations nest almost entirely on artificial nest sites, becoming an iconic site in the Chesapeake Bay.

What you can do

To protect osprey, consider using non-toxic pesticides or chemical-free cleaning products to curb the amount of toxic contaminants entering the water. You can also follow safe and legal disposal methods for paint, motor oil and other household chemicals, and keep pharmaceuticals out of waterways by returning unused medicine to a consumer drug return location.