Updates from the Field: American Oystercatcher Monitoring on the Delaware Bay

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by Emmy Casper, Wildlife Biologist

Welcome back to the second season of American Oystercatcher monitoring on New Jersey’s Delaware Bay beaches! CWF, and our partners at the Wetlands Institute and USFWS, have returned to the Bayshore to continue our research project funded by the National Fish and Wildlife Foundation (NFWF). Last year, the CWF-led team surveyed 29 miles of Bayshore beaches, monitored 19 nesting pairs, banded seven adults and four chicks, and conducted invasive species removal. This year, we’re excited to build on that progress and learn more about this previously understudied oystercatcher population.

This American oystercatcher pair nested in a horseshoe crab shell, perfectly embodying the vibe of the Delaware Bayshore.

With just a month and a half into the nesting season, we have officially recorded 17 nesting pairs, just two shy of our total pairs in 2023. While we were happy to see most of our banded birds return to the Bayshore, two banded adults (including Holgate-born “Alfredog”) are notably missing this year. Unsurprisingly, many birds are nesting in the same locations as last year, but we have observed some shuffling and redistributions. For example, “Crouton,” a banded bird that nested near Fortescue in 2023, is currently tending a nest at Heislerville WMA, 12 miles away from its original territory. We have also documented nesting pairs at three new sites that did not have nests last year, which provides additional evidence for oystercatcher movement around the Bayshore.
Similar to last season, we are continuing to monitor our active oystercatcher nests with game cameras. While predation events were relatively low last year, this season appears to be a different story. Already, we have lost nine nests to predators (5 to fox, 2 to raccoon, 1 to mink, and 1 to an unknown mammal). Spring tides and adverse weather have claimed at least an additional three nests, two of which were lost just prior to their expected hatch date. While this is not the start we had hoped for, it is early enough in the season for the oystercatchers to try again and renest.

Predator activity is higher on the Bayshore compared to last season. We even recorded our first observation on coyotes on Delaware Bay beaches.

Despite some early setbacks and challenges, there have been some bright spots. In partnership with The Wetlands Institute, we have added four newly banded adults to the population so far, which brings us closer to our goal of at least one banded adult in each nesting pair. We are also very excited to partner with the Cape May Point Science Center and Cellular Tracking Technologies to deploy GPS transmitters on up to five adult oystercatchers this season (future blog post coming soon!). Finally, we’ve been working hard to conduct outreach in the local communities of Cape May and Cumberland Counties by tabling at events and presenting to the public about the Delaware Bay Oystercatcher project. In many ways, the 2024 season is just getting started, and we’re excited to see how the rest will unfold for the Delaware Bay oystercatchers. Stay tuned for more updates!

CWF Biologist Emmy Casper attended the Horseshoe Crab Festival in Fortescue this May, where she educated the public about oystercatchers and helped kids create their own “bird band bracelets.”

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