Ocean Wanderers

Seabirds Traverse the Waters off the Cape’s Coast

Childhood Memories of a Born Naturalist

I was about 8 years old and sitting quietly in a small skiff, surrounded by a seemingly endless sea. My Dad would bring me out to catch cod and mackerel on summer days.

Sometimes my big sister Madeleine would accompany us. We were carefree, never worried about fog setting in, or the wind picking up. We just dealt with whatever came our way and carried on.

The purpose of these trips of course was to catch fish. Some days there were so many fish that Dad would tie monofilament and jigs around our wrists and we’d jig two lines, nearly filling the small boat with shiny, flapping mackerel.

But as I waited in between bites, I searched across the horizon. All I wanted was to see another small black bird come fluttering out of nowhere, zig-zag past my hands and fly off again, but where was it headed?

At times there were hundreds of seabirds. I was astounded, amazed, and beyond curious about these cardinal-sized birds that I’d never seen on land.

Days later, my Dad came home from work and dropped a book about ocean birds on the kitchen table. “Here’s a book about those birds you were studying offshore the other day.” Hmmm… I guess he had been watching me marvel at these oceanic wonders.

Photo courtesy of Gerry Beetham
Photo courtesy of Gerry Beetham
WILSON’S STORM PETREL: After fledging from a burrow, (often snow covered in the region of coastal Antarctica and the southern tip of South America), the Wilson’s storm petrel may spend up to nine years at sea, returning to the same area of the nesting burrow where it hatched. Sexual maturity is reached at 4-5 years of age. A small, black, white-rumped petrel about the size of a northern cardinal, this bird patters, with legs dangling, over the water’s surface. Often seen in large foraging groups, the name petrel is derived from Peter, and more specifically Saint Peter in the Christian faith who attempted to walk on water.
WILSON’S STORM PETREL: After fledging from a burrow, (often snow covered in the region of coastal Antarctica and the southern tip of South America), the Wilson’s storm petrel may spend up to nine years at sea, returning to the same area of the nesting burrow where it hatched. Sexual maturity is reached at 4-5 years of age. A small, black, white-rumped petrel about the size of a northern cardinal, this bird patters, with legs dangling, over the water’s surface. Often seen in large foraging groups, the name petrel is derived from Peter, and more specifically Saint Peter in the Christian faith who attempted to walk on water.

Ocean-Bound Birds

We call them pelagic birds. The word pelagic means “relating to the open sea.”

These seabirds include the tiny Wilson’s storm petrels I’ve loved since those childhood fishing trips, shearwaters, fulmars, gannets, kittiwakes, and several other species that only come to land to nest. Otherwise, they spend the rest of their lives at sea.

On any given day of the year, you can stand on the eastern edge of the North American continent, which is the outer beach from Provincetown to Chatham, and look east. Out there amid the tumult of ocean waves there are more than a million birds, some within sight and some beyond the horizon, all surviving on the open sea.

It’s such a rich and diverse marine biome. A biome is defined as a large naturally occurring community of flora and fauna occupying a major habitat, which in this case is the complex marine ecosystem of the Atlantic Ocean.

SOOTY SHEARWATER: Like the great shearwater the sooty shearwater is also a southern hemisphere nester. They’ll nest in the Falkland Islands, southern Chile, and on islands along the coastlines of Australia and New Zealand. Easy to identify, the sooty shearwater is brown overall with pale wing linings, meaning the underside of the wings. This bird glides and flaps on stiff wings and may be seen offshore during our summer months.
SOOTY SHEARWATER: Like the great shearwater the sooty shearwater is also a southern hemisphere nester. They’ll nest in the Falkland Islands, southern Chile, and on islands along the coastlines of Australia and New Zealand. Easy to identify, the sooty shearwater is brown overall with pale wing linings, meaning the underside of the wings. This bird glides and flaps on stiff wings and may be seen offshore during our summer months.

Migration Paths

During the warmer months from May through September, pelagic birds inhabit the North Atlantic. These trans-equatorial migrants (migrants that cross the equator) nest during the southern hemisphere’s summer, which is of course, our winter since the Earth’s northern and southern hemispheres have opposite seasons.

During late February and into March the hardy seabirds begin their migration northward, arriving here in the waters east of Cape Cod during May and June.

The three most widely recognized trans-equatorial migrants that we observe here during our summer months are the great shearwater, the sooty shearwater, and the Wilson’s storm petrel.

Two of these birds nest in burrows on islands around the continent of Antarctica, while the sooty shearwater nests on islands around New Zealand, Australia, and the Falkland Islands. They then migrate north during their winter (which is our summer) and are observed throughout the North Atlantic Ocean.

There are many species of birds that winter along the coastlines of the Canadian Maritimes of New Brunswick, Nova Scotia and Prince Edward Island, Iceland, northern Europe, and the Mediterranean to spend a great deal of the year in the ocean environment. The open North Atlantic Ocean is alive with millions of birds throughout all months of the year.

Peter Trull had the opportunity to work on a project with biologists from the Stellwagen Bank National Marine Sanctuary attaching satellite tags onto the backs of great shearwaters. The tags have proved resilient and stayed with many of the birds on their complete migration from the waters off Chatham to the nesting grounds in the southern Atlantic Ocean. This map shows the migration route of twenty great shearwaters as tracked by satellite.
Peter Trull had the opportunity to work on a project with biologists from the Stellwagen Bank National Marine Sanctuary attaching satellite tags onto the backs of great shearwaters. The tags have proved resilient and stayed with many of the birds on their complete migration from the waters off Chatham to the nesting grounds in the southern Atlantic Ocean. This map shows the migration route of twenty great shearwaters as tracked by satellite.

Adaptations for a Life Spent at Sea

The far-reaching flight abilities of Cape Cod’s pelagic birds may take them anywhere from Chatham to Grand Manan Island in the Bay of Fundy to the waters off Nova Scotia out to George’s Bank and back to the waters south of Monomoy.

They are true ocean wanderers. They rest on the ocean when they’re tired. When foraging for food, their diet focuses on plankton, fish, squid, and a myriad of vertebrates and invertebrates that are easy to find in this vast environment.

Typically, we will only observe them if we are out in a boat, perhaps fishing, whale watching or just enjoying a day offshore.

How can these pelagic species spend years at sea without fresh water to drink? You’ll notice a small tube-like structure on the upper mandible of the beak. Many oceanic birds have this well-developed structure as a means of secreting salt from their blood stream.

These species have a supraorbital gland (supra = above; orbital = the eye) that acts quite simply like a kidney, drawing salt out of the bloodstream and secreting it through the nasal passage, the “tube.”

You may see a gull vigorously shake its head as it stands on a piling or other perch. This is a way to release the liquid concentration of saline from its supraorbital gland, often called a salt gland. While gulls, loons and gannets, among others lack the visible tube, it is clearly evident in several photographs here. This unique adaptation for ridding the body of salt primarily exists in species that spend years at sea without ever touching land.

CORY’S SHEARWATER: This is the largest of the shearwaters found in the North Atlantic Ocean. The Cory’s is brown overall with a large yellow beak, easy to identify by its large size and pale coloration. This bird nests in the eastern Atlantic Ocean around the Azores, the Canary Islands and on the Madeira Islands. It roams the open Atlantic from Greenland to waters east of Cape Cod, and south to the Cape of Good Hope.
CORY’S SHEARWATER: This is the largest of the shearwaters found in the North Atlantic Ocean. The Cory’s is brown overall with a large yellow beak, easy to identify by its large size and pale coloration. This bird nests in the eastern Atlantic Ocean around the Azores, the Canary Islands and on the Madeira Islands. It roams the open Atlantic from Greenland to waters east of Cape Cod, and south to the Cape of Good Hope.

Discover the Pelagics Off the Cape Cod Coast

Through the fishing trips of my youth, and by reading many more books, I became familiar with each of the species that frequent the Cape Cod coast. It’s amazing how childhood experiences can spur a lifelong appreciation and passion for learning about birds and the natural world.

These days I enjoy sharing my expertise by teaching about natural history and how we can protect the Cape’s fragile resources, including the preservation work of local land trusts like Harwich Conservation Trust, Chatham Conservation Foundation, Orleans Conservation Trust and Brewster Conservation Trust.

Check out the photos to become familiar with some of the pelagic birds that inspired the 8-year-old me. These represent a small sample, but are the most common pelagic birds seen offshore during our summer months.

Throughout the year we may gaze seaward to also observe jaegers, members of the alcid family which includes razorbills, murres, dovekies, black guillemots, and puffins, up to 10 or 11 species of gulls, northern gannets, northern fulmars, and phalaropes.

Altogether they make up a diversity of seabirds living on the open ocean off our sandy peninsula.

MANX SHEARWATER: A small dark brown and white shearwater that nests on both sides of the Atlantic Ocean. In the western Atlantic which is the area of ocean off our coast, these birds travel from Massachusetts to Newfoundland, and from Great Britain to islands off Africa in the eastern Atlantic. Like other shearwaters, this species lives at sea, only coming to land to nest in colonial burrows. This is a small, dark mantled, fastflying shearwater that may be seen east of Cape Cod on any summer day.
MANX SHEARWATER: A small dark brown and white shearwater that nests on both sides of the Atlantic Ocean. In the western Atlantic which is the area of ocean off our coast, these birds travel from Massachusetts to Newfoundland, and from Great Britain to islands off Africa in the eastern Atlantic. Like other shearwaters, this species lives at sea, only coming to land to nest in colonial burrows. This is a small, dark mantled, fastflying shearwater that may be seen east of Cape Cod on any summer day.

Story and bird photos by Peter Trull