When CWF began monitoring American oystercatchers nesting on the Delaware Bay this past spring, we also set out to place field-readable bands on as many oystercatcher adults and chicks as logistically possible. Band resights allow biologists to collect a wealth of information about site fidelity, habitat use, dispersal, and migration, especially when data is collected over many years. Since the Delaware Bay population of oystercatchers was previously unmonitored, we have a lot to learn about their life histories and how they may differ from other oystercatchers in the state, if at all. Where are these birds staging and wintering? Do breeding adults return to the same mates and nesting locations each year? Where do fledged chicks disperse, and will they return to their natal grounds on the Delaware Bay to breed upon reaching sexual maturity? Banding efforts, combined with resight data reported by biologists, dedicated volunteers, and the general public will help answer these questions (and more) as we increase the number of marked individuals on the Bayshore.
Orange C41 (aka “Crouton”) being equipped with a metal federal band on the lower leg. The color of the field-reable bands on the upper legs represents which state the bird was banded in (New Jersey and New York use orange), while the alphanumeric code on the band is unique to the individual bird. All handling of birds is conducted by trained individuals under proper permits.
When looking at the expansive mudflats along the marshes of the Delaware Bay, it is hard to imagine that the area was once densely vegetated and home to a variety of bird species. This spring, CWF began work on a new marsh restoration project funded by the National Fish and Wildlife Foundation and led by Ducks Unlimited and the U.S. Fish and Wildlife Service (USFWS). CWF was contracted to assist with biological monitoring at sites targeted for marsh restoration along New Jersey’s side of the Delaware Bay. Restoration efforts for our sites are being directed toward mudflats that exist due to significant physical alterations made to the marsh in the past. The story of how these mudflats came to be lies in the area’s history and roots in salt hay farming.
As early as 1675, settlers arriving on the Delaware Bay built dikes in salt marshes to protect land from saltwater inflow and create an environment more conducive to salt hay farming and development. One of the most important types of salt hay harvested along the Delaware Bay was Spartinapatens, a crop that was widely used as bedding and feed for livestock due to its high nutritional value. By the mid-1800s, at least 14,000 acres of marsh were impounded in Salem County alone with comparable areas altered in both Cumberland and Cape May counties (Cook, 1870). Impoundments restricted tidal flow within the marsh, which stopped the natural process of marsh accretion in which sediment is consistently added to the marsh to increase its elevation. Additionally, drier conditions exposed marsh soil to too much air, resulting in the breakdown of soil and further loss of elevation.
Salt hay farming circa 1940’s. Photo retrieved from”From Marsh to Farm: The Landscape Transformation of Coastal New Jersey,” by Kimberly R. Sebold. Retrieved through https://www.nps.gov/parkhistory/online_books/nj3/contents.htm
This past winter, CWF announced a new project designed to study and monitor the population of American oystercatchers breeding along the New Jersey side of the Delaware Bay. In addition to locating nesting pairs and tracking their success, our goal is to better understand how oystercatchers utilize the bayshore habitats and what factors threaten their productivity. The data we gather with our partners at The Wetlands Institute and U.S. Fish and Wildlife Service will be used to inform future management decisions. We spent the past few months working hard to conduct the project’s first season of monitoring, and we are happy to say that we have made significant progress in beginning to unravel the mysteries surrounding this understudied population.
Delaware Bay American oystercatcher study area. Most oystercatcher pairs this season were concentrated in the bay beaches between Stipson Island and Heislerville WMA.
Since so little is known about this subpopulation of oystercatchers, we had a lot of ground to cover in our first season of fieldwork. First, we had to locate any breeding oystercatcher pairs across 35 sites spanning approximately 45 miles of bayshore from Cape May Point to Sea Breeze. Luckily, we had a head-start based on a preliminary census survey from 2021 that documented some already existing pairs as well as some sites with potentially suitable nesting habitat. We were also fortunate to have a dedicated seasonal technician assisting with the heavy workload. That said, figuring out how to access many of these sites was definitely a learning curve. We quickly discovered that many beaches were only reachable by boat or kayak and only during a narrow window of tide and wind conditions. Other sites were walkable, but only at peak low tides, which meant our surveys couldn’t take too long without risking becoming stranded by the rising tide.
In the May 16th blog, Shorebird Stewards On the Bay in May, it’s mentioned that some beaches along the Delaware Bay have restricted access every year from May 7th to June 7th. This is due to the migratory shorebirds that travel thousands of miles and need a place to stop to feed. Our beaches contain excellent food sources to help birds gain weight to continue their journey- horseshoe crab eggs. They are filled with fat and protein. The Delaware Bay is the largest spawning area for horseshoe crabs in the world!
Now what do the Shorebird Stewards, such as myself, do all day? We monitor our assigned beaches and educate the public about this incredible phenomenon! My favorite beaches are Roosevelt Blvd. beach and Cook’s Beach because I see the most active flocks of shorebirds at these locations.
A group of the infamous Red Knots: Calidris canutus, Semipalmated Sandpipers: Calidrus pusilla, and Ruddy Turnstones: Arenaria interpres, at the beach on Roosevelt Blvd., photo: C. Franceschini
On a quiet day with not many people to educate, there are many things for us Stewards to do. Some Stewards read their books, watch movies, listen to music/podcasts, color/paint, take walks, research, etc. I do all of the above! Since we have a love for these special shorebirds, most Stewards also birdwatch! It’s a must to bring your binoculars or scope to observe these beautiful birds. Sometimes, you observe other interesting animals, too!
American Oystercatcher at Cook’s beach: Haematopus palliatus photo: C. FranceschiniBald Eagles, Haliaeetus leucocephalus, photo: C. Franceschini
Another activity to do in the down-time is to flip the spawning Atlantic Horseshoe crabs, Limulus polyphemus, back onto their legs so they can crawl back into the bay. When the tide rise, these crabs get overturned by the waves and have no way of returning back to their feet! Personally, this is my favorite activity to do. When you return after your “crab walk”, you get to see the tracks of their feet traveling back into the bay where they belong. Below on the left is a picture of flipped and rescued crabs: the one on the left is a male who decided to bury himself in the sand to preserve water until the tide comes back in, and the one on the right is a male who decided to make the trek back into the bay. When the tide comes in, the horseshoe crabs come up and begin spawning. Pictured below in the middle is an example of how crowded the beaches get with these creatures! On the right, is a photo of a tagged crab I found, and reported it to the US Fish and Wildlife Service so that they can collect data on the tagged crabs.
You can also get involved with helping these critters! “Return the Favor” is an organization dedicated to conducting beach walks to flip overturned horseshoe crabs on the NJ beaches of the Delaware Bay. You can join public walks that are held by walk leaders or sign up to be a volunteer and conduct your own walk (until July 15th, 2023 or next year). I am a volunteer and walk leader and it is one of my favorite things to do. Flipping horseshoe crabs is such a special event because that means you’re saving those crabs so they can continue to spawn and produce eggs for the shorebirds. With your help, you could help save hundreds of crabs just by flipping them over! Of course I had to capture this special moment of me flipping a crab (picture below)!
On these walks, you experience much more than just crabs. You get to see other wildlife that emerges during dusk or dawn. You can also go on the closed beaches to save the crabs that can’t be rescued during the day. During my walk, I got to see thousands of horseshoe crab eggs!
C. FranceschiniHorseshoe crab eggs photo: C. FranceschiniFemale horseshoe crab, photo: C. Franceschini
Over the winter, biologists from CWF, Ducks Unlimited, USFWS, and Partnership for the Delaware Estuary visited sites like this marsh in Dix Wildlife Management Area to assess their restoration potential and strategize monitoring plans.
This spring, CWF will begin fieldwork for a new marsh restoration project along the Delaware Bay. The ambitious project, funded by the National Fish and Wildlife Foundation and co-led by Ducks Unlimited and the U.S. Fish and Wildlife Service, aims to implement cost effective and low-tech marsh restoration techniques in New Jersey and Delaware salt marshes. Restoration plans will be designed to create, protect, and/or enhance habitat for multiple marsh-dependent species including black rails and saltmarsh sparrows. As a project partner, CWF will provide two seasons of biological monitoring assistance at the New Jersey sites. This week, WHYY published an article about the project, featuring representatives from CWF and other project partners. Click the link below to read the piece and learn more about some of the important work being done by the Delaware Bay!
