Candid Camera: The Role of Game Cameras in American Oystercatcher Monitoring

by Emmy Casper, Wildlife Biologist

This year, CWF embarked on a new, ambitious project to monitor and characterize the previously understudied population of American oystercatchers nesting along the Delaware Bayshore. Since so little is known about this breeding population, we had a lot of ground to cover this first field season, both physically and metaphorically. One of the goals of the project is to characterize threats to oystercatcher nest success on the bayshore, whether it be predators, flooding, or something else entirely. It sounds straightforward, but when you consider the span of the project (35 sites across approximately 45 miles of bayshore), monitoring nesting pairs gets a bit more challenging. That’s where game cameras come in.

.CWF biological technician Caroline Abramowitz deploying a trail camera to monitor an oystercatcher nest.

Game cameras are an extremely useful tool for wildlife monitoring. Cameras deployed at nest sites can provide valuable information about oystercatcher behavior, predator presence, and nest fate (whether the nest hatched or was lost prior to hatching). This is especially important for our Delaware Bay sites, many of which are remote and cannot be monitored as frequently as other locations. Game cameras enhance our in-the-field monitoring and can pinpoint the true cause of nest loss that would otherwise be difficult to determine in the field. Accurate knowledge of nest fate and predator presence is crucial for understanding which factors significantly impact oystercatcher success along the bayshore.

I will admit, after looking through hours of game camera footage it begins to feel like you’re binge-watching a reality TV show series. Keeping Up with the Oystercatchers, anyone? Like any good reality TV show, there’s always a bit of entertaining drama, like an oystercatcher pair’s ongoing feud with their Canada geese neighbors. Other moments, like a chick predation or nest loss, can be heartbreaking and difficult to watch. For almost every sad moment, there is something beautiful to see, like a rainbow over a nest or parents caring for their freshly hatched chicks. And there are some seriously surprising plot twists. We were most surprised this year by the constant presence of bald eagles at oystercatcher nests. Imagine our shock when we watched two juvenile eagles accidentally destroy an oystercatcher nest with a piece of wood!

We were able to deploy game cameras at almost every bayshore oystercatcher nest we monitored this season. Processing all of the footage can be time consuming, but the results have been worth the work. We’ve already been able to gain valuable information about predator communities and factors influencing nest success at each site, and we plan to continue using cameras as monitoring tools next season. Check out some of the highlights from this season, below.

I was always entertained by this oystercatcher pair who always found themselves surrounded by Canada geese. The birds tolerated each other most of the time, but every so often the oystercatchers would take out some frustration on their pesky neighbors.
Although a variety of mammals (e.g., mink, raccoon, river otter) were captured on film, foxes were the most common nest predator and caused at least five nest losses.
Great Horned Owls were captured on cameras at multiple sites. We suspect their presence may explain some of the chick losses we documented this season.
American mink investigating an oystercatcher egg. Interestingly the mink never actually consumed an egg, even after returning to the nest on multiple nights.
The best part of reviewing camera footage is being able to witness the chicks hatch. Capturing the moment of hatch is also important data to collect – it allows us to confirm nest fate and verify the number of chicks. Can you spot the three chicks in this photo?
Camera footage revealed bald eagles as unexpected “villains” this season. Eagle presence often caused incubating oystercatchers to leave their nests exposed for extended periods. You can see the exposed oystercatcher eggs close to the middle of this image, behind the juvenile eagle’s back. 
In this “plot-twist” moment, two juvenile eagles grappled with each other within close proximity to an oystercatcher nest. One of the eagles tried to carry a piece of wood and dragged it over the nest, cracking the eggs in the process.
My favorite capture of the season – a perfectly timed rainbow over an incubating oystercatcher.

2 thoughts on “Candid Camera: The Role of Game Cameras in American Oystercatcher Monitoring

  1. Last summer there was a nest right on the beach in Belmar,NJ
    Right by the handicap walkway .

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