Behavior

Meet the New Kid on the Marsh!

By Meredith Wray and Emmy Casper, Conserve Wildlife Foundation of New Jersey and Samantha Collins, The Wetlands Institute

Orange 07 on its wintering grounds at Cedar Key, FL in 2015. Image courtesy of Pat Leary.

During a recent American oystercatcher (Haematopus palliatus) survey within the marsh islands of Great Bay Boulevard Wildlife Management Area (New Jersey), Conserve Wildlife Foundation biologist Emmy Casper and biological technician Meredith Wray observed an undocumented pair of adult oystercatchers acting defensive, a telltale sign that they were hiding something. Sure enough, a healthy chick appeared from the marsh, hatched from a nest so well hidden it had gone undetected until now!

The surprises didn’t stop there. One parent, Orange 07, was banded as a chick on nearby Hither Island in 2010 and has since been spotted regularly on its wintering grounds at Cedar Key, Florida. At an impressive 16 years old, this is its first documented nesting record – a reminder of how little we know about marsh-nesting oystercatchers in New Jersey compared to their beach-nesting counterparts.

Thanks to a one-year grant from the Atlantic Flyway Shorebird Initiative through the National Fish and Wildlife Foundation, The Wetlands Institute and partner organizations Conserve Wildlife Foundation of New Jersey and Stockton University we were able to initiate the necessary work to give oystercatcher populations nesting in the salt marshes of New Jersey the attention they deserve, we’re finally beginning to uncover stories of birds like Orange 07 across the state. Salt marshes provide important nesting, foraging, and roosting habitat for a variety of shorebird species, including the charismatic American oystercatcher. Understanding the reproductive success of American oystercatchers in salt marshes is crucial because their success can reflect the quality of the habitats they occupy. Pairs nesting within salt marsh habitats often have received limited attention to fully understand habitat selection, reproductive success, and threats to nesting.

American Oystercatcher chick. Image courtesy of Meredith Wray

Shortly after finding Orange 07’s chick, Conserve Wildlife Foundation staff banded it with the code Orange C87 and affectionately named it “Oopsy Daisy” – a nod to its surprise discovery. After taking some morphological measurements, Oopsy Daisy was released back into the marsh to reunite with its attentive parents. We are happy to say that since the banding, Oopsy Daisy was recently seen flying for the first time with its parents, indicating a successful fledge! Only time will tell where it will end up next, and if it will return to its natal island to raise its own family.

Through our study we are learning a lot about survey and monitoring methods for breeding pairs within salt marsh habitats so, with the hopes of future funding, we can continue to better understand how to locate and monitor nests or chicks like Oopsy Daisy. Filling these marsh data gaps could play an important role in informing state- and range-wide population trends and identifying opportunities for conservation in a changing coastal landscape.

All handling/banding was completed for research purposes and under appropriate state and federal permits.

The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government or the National Fish and Wildlife Foundation and its funding sources. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government, or the National Fish and Wildlife Foundation or its funding sources. This report was funded with support from the U.S. Fish and Wildlife Service grant F24AP01455.

Playing Nice on the Beach – Unusual Observations from a Small Island Population of American Oystercatchers

American Oystercatcher clutch. Beth Howard, Mass Audubon

American Oystercatchers are fiercely territorial, and a pair of nesting oystercatchers generally prefers some space between them and their nesting neighbors. However, there is an unusual oystercatcher oasis in Boston Harbor where nine pairs nest within a maximum distance of about 275 meters! This leads to all sorts of fun and unusual behavioral observations regarding these generally-territorial birds.

For example, Mass Audubon monitors have noticed several instances of creche-like behavior, which is when chicks from multiple broods are collectively tended by an adult or adults. This is not at all typical of American Oystercatchers. However, there are two pairs on this island who nest less than 50’ from each other each year, and for several years, they have left both broods with one adult while the other three adults go off to forage. The adult that stays with the chicks switches chick-tending duties with another adult periodically. This collaborative chick-rearing is not what we typically expect from this highly territorial and aggressively defensive species!

On this island oasis, we have also seen collaborative nesting, where a “throuple” (three adults) came together one year to lay eggs and share incubation duties. Additionally, we have seen a case of adoption (by choice, not necessity!). In this situation, one pair of oystercatchers initially had three chicks and another pair had two. The pairs’ nests were within 100’ of each other, and when the chicks hatched, they often hung out together near the territorial boundary. The adults would not allow the other adults into their territories, but the chicks were allowed to freely come and go between territories. At one point, one chick from the pair that had two decided not to return, and instead joined the trio and were fed and defended by the adoptive parents as a fourth member of the brood until they all fledged. The solo chick also fledged, and continued to spend time with the other chicks, but stayed with the original set of parents.

Some Things We Learn from Banding

At the southern end of the Boston Harbor Islands is a small harbor with four small islands. As the established population of American Oystercatchers in Boston Harbor is successful, their chicks and other young oystercatchers often return to the same general area to try to establish a territory of their own. One year, a young banded bird showed up with a mate and established a new nesting territory on one of the islands. Because of the band, we were able to learn that this was a bird who was three years old and had not previously nested elsewhere.

Two American Oystercatchers on a rocky beach.

American Oystercatchers. Beth Howard, Mass Audubon

We were able to see how young birds move in and search for territories by following this bird’s nest attempts over eight years. Year after year, we saw the pair try out different sections of the same island, then different types of substrate, and eventually, three different islands before settling on what appears to be their final choice of nesting location. We can see them learning and refining their process with every attempt. They are choosing areas with more forgiving substrate, and are nesting higher above the wrack line to avoid tidal overwash. Avian predators are hard to avoid, but the pair is learning to choose locations with a good vantage point for spotting predators approaching, while also using natural features to conceal their location as well as they can.

We see a lot of oystercatchers moving through the area, and without a banded bird being part of this pair, we might not have understood that it was the same pair switching up their locations from year to year, and trying new things. Because of the bands, we are able to observe and understand a little bit more about how young birds arrive on scene, establish their own territories, learn from their prior choices, and make new decisions on where to nest each year. We can see their confidence grow as they return, claim territory, make a nest, and lay eggs earlier and earlier each year. This year, they chose a good spot and nested at about the same time as the older, more experienced pairs did. Perhaps this will be the year they fledge chicks from what appears to be their preferred territory!