Osprey Banding at Mallows Bay

July 22, 2025

A woman holding an osprey chick with large, dark eyes and downy feathers while standing in a boat. The water of a lake or bay is visible behind her. — Photo: Elena Gilroy/Charles County

Mallows Bay-Potomac River National Marine Sanctuary's Research and Outreach Coordinator Megan McCabe, had the opportunity to assist with banding juvenile ospreys in the sanctuary. Each year, Charles County, a co-manager of the sanctuary, partners with certified bird banders from the USGS Bird Banding Laboratory located in Laurel, Maryland, to attach identification bands to juvenile ospreys in the sanctuary and surrounding county parks.

Four juvenile ospreys from two different nests in the sanctuary were fitted with an aluminum ring around one leg, each stamped with a number that acts as a unique identifier for each bird during its lifespan. The juvenile ospreys, at only four to six weeks old, are not yet able to fly, meaning that catching them for banding is as simple as picking them up out of the nest and holding them while the band is fitted around the leg. This is done as quickly as possible to prevent stress to the birds and minimize the amount of time the parents are away from the nest, who often circle overhead and keep a watchful eye on their babies during this process.

Tracking and reporting banding data helps researchers better understand migration patterns, population dynamics, and the lifespan of ospreys and several other bird species. As a raptor at the top of the food chain, ospreys are a keystone species in the sanctuary that indicates the overall health of the ecosystem. Monitoring their nesting success and tracking their movement and behavior with banding data provides insight into the stability of the population both in the sanctuary and the broader Chesapeake Bay region.

A man stands on a boat next to a large, wooden platform with an osprey nest on top, made of sticks and branches. In the background, there is a wide expanse of water under a clear sky, with a partial view of a sunken boat.

Two fluffy, mottled brown and white juvenile ospreys are nestled in a stick nest. One bird is larger and has its beak open, while the smaller one looks toward the viewer. The nest is high above calm water, with a distant treeline and clear sky visible in the background.

The banding team banded four juvenile ospreys from two separate nests - one located on the bow of the Benzonia shipwreck, and the other on a nest platform built on a piling in the sanctuary. Photos: Megan McCabe/NOAA

The wooden shipwrecks of Mallows Bay-Potomac River National Marine Sanctuary provide prime nesting locations for many different bird species, including the iconic osprey. These distinctive hawks are at the top of the food chain in the Chesapeake Bay watershed, and are talented fishers, often spotted plunging feet-first into the water to catch fish.

This work supports NOAA's ability to fulfill its statutory mission under the National Marine Sanctuaries Act Section 309 to support, promote, and coordinate research and long-term monitoring of resources and natural processes that occur in national marine sanctuaries.