Guess who’s back?
Osprey have returned to the Delaware Estuary from their seasonal southward migration — and by now, they’re not just nesting. They’re hatching chicks.
Every March, osprey make their seasonal return, with nesting kicking into gear in April. These large birds — roughly the size of a goose — build impressive nests atop trees, utility poles, and specially erected platforms. They’re devoted recyclers, reusing and expanding the same nest year after year. Some nests reach six feet wide and 13 feet deep.
Osprey have a dramatic hunting style: a feet-first plunge into the water to snatch fish swimming near the surface. Oily feathers, broad wings, and a unique reversible toe help them burst back into the air — often with a fish firmly in their talons. They succeed roughly 25 to 70 percent of the time, typically taking just 12 minutes to make a catch.
Life isn’t without its hazards. Fledgling osprey can fall prey to bald eagles and great horned owls; raccoons occasionally raid their eggs; and rival raptors have been known to commandeer nests and steal freshly caught fish. Human activity adds additional pressure. The good news: in recent years, osprey populations in the Delaware Estuary have become more stable and trended upward, thanks largely to reduced contaminants and improved conservation measures.
But the work isn’t done. Despite this progress, there is growing concern that osprey aren’t reproducing as successfully as they should. While stricter regulations have reigned in legacy pollutants like DDT and PCBs, emerging contaminants are drawing new scrutiny. Current exposure levels fall below thresholds of known concern — but ongoing monitoring remains essential for understanding the long-term effects on the food chain and the broader ecosystem.
This information was largely taken from the 2022 Delaware Estuary Technical Report for the Delaware Estuary Basin and the 2023 State of the Estuary Report.
THINGS YOU CAN DO
• Volunteers are crucial for monitoring nests and the success of Osprey populations. To get involved,
check out the Osprey Watchers and help monitor nest sites near you.
• You can also contribute data about any bird species you see by contributing to a community science
program like eBird.
• If bird watching is not your strength, you can still lend a hand by helping to build and maintain nesting
sites near you, or learn bird calls with apps like Merlin Bird ID.
