Conserve Wildlife Blog

Expanding the Search for American Oystercatchers Breeding in New Jersey

June 28th, 2024

By Todd Pover, Senior Wildlife Biologist 

CWF has played a major role in helping monitor breeding American oystercatchers in New Jersey ever since surveys were initiated in the state just over two decades ago in the early 2000’s. Most of the statewide effort, conducted by a variety of partners, has been focused on pairs nesting on the sandy barrier beaches of the Atlantic Coast, in conjunction with efforts there to monitor and manage other beach nesting birds, such as piping plovers and least terns. These sites are often those beaches that are highly recreated and most used by beachgoers, public beaches where these species need added protection to hatch nests and raise their young chicks.

American oystercatcher nest found earlier this spring along the Raritan Bay.

At the same time, from the start of oystercatcher monitoring in New Jersey, we knew that a portion of the population nested in our marshes, on sandy fringes and patches on the islands from Barnegat Bay to the Cape May Canal. How many pairs nest in marsh habitats is still not entirely known, although a nearly state-wide survey early on in the monitoring effort suggested it was a substantial number, perhaps two to three times the portion nesting on sandy barrier beaches. Meanwhile, the number of pairs nesting on the sandy barrier beaches and islands of New Jersey has risen to about 150 pairs, nearly triple the tally when monitoring first started. While we believe that some of that increase is the result of improved conservation measures and increased reproductive success, without a solid accounting of nesting in our marsh systems, part of the increase might also be the result of movement of pairs from the marsh to barrier island sites, perhaps as a result of sea-level rise disproportionally impacting marsh nests.

Although a full statewide survey continues to elude us in New Jersey – the logistical and resource challenges to mount such a survey are high – we are starting to piece together some of the other habitats in New Jersey being used by oystercatchers. Rooftop nesters have now been documented, mostly in the Atlantic City region where the right kind of buildings exist (think casino rooftops) for this unique nesting adaptation by oystercatchers. In 2022 CWF received a grant from the National Fish and Wildlife Foundation to monitor the largely unstudied Delaware Bay population. Our surveys indicate that the bay is currently only hosting about 20 breeding pairs but based on our assessment of suitable habitat and observation of bayside movements, there is room for growth.

And just this year, CWF received a generous donation from New Jersey Resources, the parent company of New Jersey Natural Gas and NJR Clean Energy Ventures, to look into the presence and distribution of American oystercatchers on the Raritan Bay and estuarine systems in Monmouth County, another region that has not gotten much previous attention. Those surveys are still being conducted, so data are just preliminary, but early results suggests that the amount of suitable habitat in the lower Raritan Bay is limited and therefore the number of breeding birds present, is low, as well, with just 4-5 pairs identified so far. Likewise, the estuarine systems in Monmouth County have limited habitat for oystercatchers and much of it is highly used by boaters and other personal watercraft users. That said, the river systems in particular still appear to play a key role for foraging by breeding adults nesting on the barrier beaches that front the river or along inlets.

While two decades of monitoring sounds like a long time, when you consider that oystercatchers can live that long, relatively speaking we still have a lot to learn with continued research. These smaller studies are filling in information gaps, although ultimately, we hope to have a clearer understanding of the full statewide picture of one of our state’s most charismatic coastal species.

Photo courtesy of Jim Gilbert

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