Just as summer’s heat envelopes us, there’s more worrisome news about ospreys. Dr. Bryan Watts, Director of the Center for Conservation Biology (CCB) at William & Mary, has released an inventory of active osprey nests along Virginia’s Eastern Shore Seaside.
His report’s title tells the ugly story: “Osprey Population along the Seaside of the Delmarva Peninsula has Collapsed.” Where a CCB survey in 1987 recorded 83 pairs, this year’s survey recorded only nine pairs between Fisherman Island and the Chincoteague Causeway.
“We’ve been watching them since the 1990s,” Dr. Watts tells us, “ and the loss rate has really ratcheted up in the last few years.” This population collapse is a concern not only for the loss of an iconic, well-loved bird but also for what it says about the condition of this coastal environment that appears otherwise pristine.
Why the failure? Dr. Watts’s careful summary says: “The underlying causes of this population decline are unclear. Although there have been changes in nesting substrates (like duck blinds, dead trees, navigational aids, or nesting platforms) over time, the availability of nesting substrate does not appear to be a primary factor. Suitable structures remain widely available and many substrates that were used for extended periods are now vacant.
“It is possible that bald eagles may have impacted osprey along the seaside. The bald eagle population within the area has more than tripled since the 1980s. However, the density of eagles continues to be a small fraction of that found within the upper tributaries of the Chesapeake Bay where ospreys continue to thrive.”
He goes on to report, “The most likely cause of the decline is prey availability. However, no osprey diet studies have ever been conducted within this site, and we know very little about trends in fish availability. During the 1970s and 1980s, the highest density of nesting pairs was skewed to the southern portion of the area around Fisherman and Mockhorn Islands. These birds could be observed flying out to the mouth of the Chesapeake to forage. Pairs have declined by more than 90% within this portion of the study area.”
When looking for causes, questions arise about the availability of menhaden for ospreys to eat in the “southern portion of the area around Fisherman and Mockhorn Islands.” Some believe menhaden industry giant Omega Protein is competing with the ospreys for their food.
A recent email from the Menhaden Fisheries Coalition notes that the reduction fishery of Omega Protein has not set any purse seine nets in this area this year. However, the map below shows sets for both the reduction fishery and the bait fishery (used in crab pots and recreational angling) in and around the Chesapeake between 2020 and 2024:
The information comes from the Atlantic States Marine Fisheries Commission’s (ASMFC) Atlantic Menhaden Work Group Report on Chesapeake Bay Precautionary Management — April 2025. The ASMFC report states that osprey males may fly up to 10 kilometers (6.25 miles) from their nests as they hunt for fish. Thus, males from the Fisherman Island area could certainly forage for menhaden northwest along the Bayshore toward Kiptopeke as well as northeast along the seaside.
At least a part of the reason for the concentration of purse seine sets on each side of Cape Charles and Fisherman Island is the saltwater flow that hugs the shoreline into the Chesapeake from the Atlantic, carrying schools of menhaden with it. The fresher currents flowing down from the Bay’s tributaries tend to hug the western shore and spill into the Atlantic close to Cape Henry.
Dr. Watts and CCB continue to study and inventory osprey nests up and down the Bay while answers about the root cause of the Eastern Shore’s osprey decline remain unclear.
