Starting in late July, the breeding shorebirds of the treeless Arctic tundra begin streaming south, fanning out across North America.
The wading birds characterized as shorebirds are a diverse group of species in the order Charadriiformes, and hundreds of thousands of these birds migrate along Cape Cod’s coastlines every summer through the Atlantic Flyway. For many of these birds, the Cape is a vital stopover to rest and feed on local delicacies like marine invertebrates (worms, insects, small crabs, other intertidal and marsh morsels) before continuing thousands of miles southward to their wintering grounds.
The most important foraging areas for shorebirds are found within the wild and relatively inaccessible wilderness of Monomoy National Wildlife Refuge, 7,600 acres of barrier beach, wetlands, dunes and scrub brush habitat, and the 44,600 acres of the Cape Cod National Seashore. Let’s give honorable mention to the 4,700 acres of Barnstable’s Sandy Neck, too.
However, unusual shorebird visitors can turn up on any beach on the Cape and the Islands during the months of July and August. Good places to look for migratory shorebirds locally include Bell’s Neck Conservation Lands (at low tide) and Red River Beach in Harwich. Forest Beach Conservation Area and Morris Island, part of Monomoy National Wildlife Refuge, can offer shorebird sightings in Chatham. On popular beaches, it is best to time your visit for either early or late in the day on an incoming tide. Weather systems during this time of year often promise to bring hordes of shorebirds to the coast.
In taxonomy, North American shorebird families range from the stocky plovers to the striking large black and white oystercatchers to slender, long-legged stilts and avocets to sandpipers, a large group of birds too diverse to generalize. Some shorebird species do commonly breed on the Cape and the Islands, such as eastern willet, piping plover, killdeer, and American oystercatcher.
In late summer, these species begin to flock up amongst their kind, and they join the large groups of common, least, and federally endangered roseate terns that occupy beaches while “staging” for migration, which is a critical time period for rest and feeding. Juveniles may be commonly seen amidst our summer breeders as well. The most important staging sites are limited to remote beaches with few human visitors, especially South Monomoy Island.
Commonly seen Arctic breeders on their migratory journeys include least sandpipers, sanderlings, ruddy turnstones, and semipalmated and black-bellied plovers. These species will be found in smaller groups of individuals on beaches like Red River in South Harwich. Of these, sanderlings are perhaps the most familiar shorebirds to casual birders as they chase the waves and spend their winters on Cape Cod. Subarctic boreal breeders like greater and lesser yellowlegs and short-billed dowitchers are also often seen wading in the water and poking their bills in the sand for a mollusk or polychaete worm meal.
Shorebirds boast many champion migratory species including beautiful chestnut-colored red knots. Red knots of the rufa subspecies breed high in the Arctic tundra, migrating from South America along the Atlantic Flyway from locations even as far as south as Tierra del Fuego. In the spring, rufa red knots famously stop in Delaware Bay to gorge on horseshoe crab eggs before continuing their 9,300-mile long flights to the Canadian Arctic. Red Knots are more commonly seen on Cape Cod in the fall, but now in small numbers. Sadly, the rufa red knot population has declined as much as 25 percent annually in recent years, continuing a decades-long population decline due to many causes, including hunting mortality in South America, a hugely increased horseshoe crab harvest in Delaware Bay, and the impacts of climate change.
Whimbrels, large and unusual curlew sandpipers that also breed in the Arctic, stop over on Cape Cod before undertaking non-stop migratory flights to their wintering grounds in the Caribbean islands and the northern coast of South America. Perhaps even more impressive are small semipalmated sandpipers, weighing under two ounces with only a 14-inch wingspan, that rely on their fat reserves to fuel a similar non-stop flight from their stopover sites in New England to coastal South American mudflats, beaches and mangrove forests. Imagine that these small winged creatures have the fortitude to fly non-stop from the northeastern U.S. to countries like Brazil and other coastal destinations in northern and central South America.
Despite the many threats that shorebirds face from climate change, storms, predation, and in some cases, hunting, bird conservationists have done great work over the past century in recovering many species from the low populations directly caused by the carnage of market hunting in South America. Like herons, egrets, terns, and many other birds, shorebirds were extensively hunted for the millinery trade as well as for food. Sadly, hunting mortality led to the possible extinction of the northern curlew, which hasn’t been seen since 1963.
With the passage of the Migratory Bird Treaty Act of 1918, the United States outlawed the “taking” (deliberate or accidental killing) of protected migratory bird species, including shorebirds with the exception of a couple of game species (American woodcock and Wilson’s snipe). This treaty protected birds in the U.S., Canada, Mexico, Japan, and Russia. In some good news for all birds, last week a federal judge re-affirmed the protections for migratory birds under the Act.
Bird conservationists also led the way in establishing the 19.6 million-acre Arctic National Wildlife Refuge in 1960, encompassing vast areas of the Brooks Range and the Alaskan Coastal Plain, which is the world’s shorebird nursery. The refuge is a pristine example of the Arctic ecosystem, where birds from six continents congregate and breed in the brief Arctic summer. The refuge’s unspoiled biological riches also include the 200,000-strong porcupine caribou herd, musk oxen, wolves, wolverines as well as grizzly and polar bears. The federal government has recently announced an oil and gas leasing program that would open the refuge to drilling, a controversial decision. Drilling and building roads and other infrastructure would destroy, fragment, and pollute sensitive habitats within the Refuge.
Locally, we must take steps to protect shorebird habitats for their current and future conservation. This requires a broad range of actions, both big (collective) and small (individual). We can purchase coastal properties for conservation purposes where beaches and salt marshes can migrate inward with sea level rise. We can restore barrier beach habitat by removing armoring structures when possible, supporting and respecting shorebird closure areas on local beaches, and improving the water quality of our estuaries. Since shorebirds see dogs as predators, it is also important to respect beach regulations, and to keep dogs leashed and away from flocks of shorebirds so they can save their vital energy stores for their long migratory journeys.
Bring a pair of binoculars on your visit to local barrier beaches and other conservation destinations to catch a glimpse of your local shorebirds. Migratory species will be most abundant over the next few weeks. And you don’t have to be a birding expert by any means to revel in the beauty of these winged visitors. Anyone who simply enjoys the fresh seaside air and softening light of late summer can also find joy in watching shorebirds and other wildlife that may cross your path.
Tyler Maikath is the Harwich Conservation Trust's outreach and stewardship coordinator. To learn more about Harwich Conservation Trust, visit www.harwichconservationtrust.org.To see more of photos by Sarah E. Devlin, visit www.sarahedevlin.com.