DELMARVA ALMANAC

Ocean City’s Summer Shorebirds

by Jim Rapp

Keep your ears and eyes open for willets and oystercatchers when you're visiting the Delmarva coast this summer.

(Willet calling) Keep your ears and eyes open for willets and oystercatchers when you're visiting the Delmarva coast this summer.

If you spend any time exploring Assateague Island or paddling on the coastal bays behind Ocean City, Maryland, you will likely recognize this signature sound of our summertime barrier islands. The bird making this raucous noise is a Willet, appropriately named for the "pill-will-willet" sound it makes. The call you just heard is from the Sibley Birds app for iPhone.

If you look towards the sound, your eyes might catch the distinctive black and white stripes that run the length of each wing when the Willet goes airborne. The wing markings revealed during flight are the only bold colors on the otherwise drab, mottled, brown-and-gray summer plumage of the Willet.

When they're not flying and calling, this long-legged, relatively tall shorebird is usually seen standing on the beach or in the saltmarsh. Willets are abundant along the Delmarva coast during the summer, where they feed, nest and raise young.

The Willet feeds by walking and wading along the shoreline, probing the sand and mud with its long, straight bill. They find marine worms, fiddler crabs, insects and small shellfish using the sensitive tips of their bills. Willets can feed day and night by just feeling for food with their beaks. In addition to their mostly seafood diet, they will also eat saltmarsh grass seeds and shoots.

On Delmarva and throughout the mid-Atlantic, Willets often breed in colonies. During the spring breeding season, males work furiously to impress females by flying, fluttering and calling loudly over their marsh nesting area.

Shallow nests made of grass are typically built in the high saltmarsh. Both parents incubate four to five camouflaged eggs, which are grayish-olive and speckled with brown spots. Only the male Willet sits on the eggs at night.

After three to four weeks, the fuzzy chicks will hatch, and the precocial babies will leave the nest the same day. The parents will teach the baby Willets how to forage, but the chicks are not provided with food from mom and dad.

Much like their shorebird cousins, the Killdeer, the parent Willets will perform a broken wing display to get the attention of predators and lure them away from vulnerable eggs and babies. Mother Willet will cease parenting after two to three weeks, but the male will remain with the chicks for a while longer.

The Willet is just one of more than 200 species of shorebird found around the world. Shorebirds are small to medium-sized birds that prefer to feed and nest along beaches and tidal mudflats, fresh and saltwater wetlands, and open prairies and grasslands. Their bodies feature slender, pointed bills for probing in the sand, mud and soil, and long skinny legs for wading in shallow water.

Shorebirds found on Delmarva include willets, oystercatchers, sandpipers, plovers, dowitchers, avocets, and stilts. Most of our Delmarva species migrate through the peninsula in the spring on their way to breeding grounds in the far north, and again in the fall when they travel south for the winter.

Only a few shorebirds breed on Delmarva. During the summer, you can find Willets breeding in the marshes of our Atlantic coastal bays, and the Chesapeake and Delaware Bays. Other local nesting shorebirds include Killdeer, Black-necked Stilt, Spotted Sandpiper, the federally threatened Piping Plover, and the American Oystercatcher.

This is Jim Rapp and you’re listening to the Delmarva Almanac. We’re talking about summer shorebirds.

Like the Willet, the Oystercatcher is a large shorebird that can be found feeding and breeding behind Ocean City and Assateague during the summer. Unlike its drab-colored cousin, the Oystercatcher is more boldly patterned, with a brown back, white belly, black head, and a large, brightly colored red bill.

You may hear the Oystercatcher's call when visiting Ocean City and Assateague. This recording is from the Sibley Birds app for iPhone:

(American Oystercatcher calling)

The Oystercatcher is named for its specialized method for feeding on oysters, clams, and mussels. These shorebirds are pros at getting to the tasty meat found inside the hard shells of bivalves. If the oystercatcher finds a clam with its shell partially open, it will quickly insert its scissor-like bill into the opening, cutting the strong muscles that pull the two shells together. With the shells unable to close, the oystercatcher can easily remove the meat. If the shell is already closed, they can use their strong bill to hammer and shatter it.
Oystercatchers also feed on marine worms and small crabs.

In areas of high density, American Oystercatchers may form breeding trios, with one male and two females tending one or two nests. They nest on the ground, usually on a marshy island with a sandy ridge above the high tide mark. The nest is a simple, shallow scrape in the sand, sometimes lined with shells.

One to four gray eggs with brown specks are usually laid by a pair, but nests tended by two females can yield up to six eggs. Males and females incubate the eggs for up to four weeks. Like the Willet, down-covered chicks hatch and leave the nest shortly after. Unlike the Willet, both parents feed the chicks for at least two months after hatching.

After the summer breeding season, Willets leave Delmarva and migrate south. American Oystercatchers can be found on the coast year-round.

Although they are fairly common today, populations of both Willets and Oystercatchers were in serious decline by the late 1800s due to market hunting and egg collecting.

In his book "Birds of America," published between 1827 and 1838, Naturalist and Painter John James Audubon wrote that the eggs of the Willet were delicious and the young birds “grow rapidly, become fat and juicy, and by the time they are able to fly, afford excellent food.” The tasty shorebirds were hunted for many years after Audubon's account, often for sale in the marketplace and without regulation to protect their populations.

During the colonial period, Delmarva's coastal residents would boat out to islands where shorebirds, gulls and terns nested to collect eggs for sale or use in their own kitchens. The practice, known as "egging," disrupted nesting seasons and contributed to a serious decline in shorebird populations up and down the Mid-Atlantic. Some eggs became so scarce that egging was adopted by hobbyists, who would seek out the rarest of bird eggs to keep as artifacts in their private collections. The name of Great Egging Island, located behind Assateague Island, is a throwback to this colonial tradition.

By the early 1900s, Willets and American Oystercatchers had almost vanished in the Northeastern U.S. due to market hunting and egg collecting. The Migratory Bird Treaty Act of 1918 banned commercial trade in birds and eggs, and populations have increased over the past 100 years. Both species have adapted to life around humans, but coastal development, bad behavior by recreational boaters who disrespect posted closure signs on nesting islands, and threats from climate change make these shorebirds vulnerable today.

One of the most important nesting areas islands on Delmarva for Willets, Oystercatchers and other species of coastal birds are the 25 acres of islands and mudflats that make up the Sinepuxent Wildlife Management Area. Located behind Ocean City and Assateague, this state-managed wildlife refuge includes Skimmer Island, Heron Island, and the newly created Tern Island. Most of the islands are closed in the summer months to allow breeding birds to nest safely. Please observe the posted closure signs that designate these islands as "off limits."

If you want to experience Delmarva's fall bird migration by kayak, canoe and stand-up paddleboard, join the expert guides leading field trips around Laurel, Delaware and Snow Hill, Maryland during the Delmarva Paddling Weekend, which will be held September 30 through October 2. For more information, please visit DelmarvaPaddling.com.

Keep your ears and eyes open for willets and oystercatchers when you're visiting the Delmarva coast this summer. Until next time, I hope this story inspires you to explore and learn more about Delmarva’s many natural wonders.

References:


http://www.allaboutbirds.org/guide/Willet/id

http://www.allaboutbirds.org/guide/American_Oystercatcher/id

http://dnr2.maryland.gov/wildlife/Pages/publiclands/eastern/sinepuxentbay.aspx