These 10 Cape Cod birds are at risk for extinction. Here's why and what's being done

Heather McCarron Cape Cod Times 

Published Oct, 28, 2022 

Editor's Note: This article was updated at 11 a.m. Oct. 28 to correct the name of Mass Audubon's Wellfleet Bay Wildlife Sanctuary science coordinator Mark Faherty.

Like the caged canaries that at one time gave coal miners an early indication of a change in the environment they should pay attention to, some species of birds are serving to sound the alarm on climate changes as their populations plummet in the face of them.

With Cape Cod among the most vulnerable landscapes, it should come as no wonder that several of the birds that feather their nests here, or that find refuge on the Cape's shores and in its estuaries and forests along their migratory routes, are counted as top sentinels of climate change ― and as heralds of the degrading impacts that are already occurring.

Ten resident and migratory bird species found on Cape Cod are listed in the 2022 "State of the Birds" report, along with 82 others observed across the country, as some of the most vulnerable.

According to the report, a collaboration of 33 science and conservation entities released on Oct. 12, these birds are suffering from population losses of 50% or more since 1970. Of these, 70 of them are highlighted as "tipping point" species that are on a trajectory to lose another 50% or more of their remaining populations in the next 50 years, or that already have "perilously small populations and continue to face high threats, but lack sufficient monitoring data."

The black-billed cuckoo, the eastern whip-poor-will and the snowy owl, all found on the Cape, are among the 10 birds of concern listed in the report. The remaining seven are listed in the subset of "tipping point" birds, according to Mark Faherty, science coordinator at Mass Audubon’s Wellfleet Bay Wildlife Sanctuary. They include the saltmarsh sparrow, the least tern, the whimbrel, the Hudsonian godwit, the prairie warbler, the semipalmated sandpiper and the ruddy turnstone.

Which Cape Cod birds on on the 'tipping point'?

While all of the listed birds are species of concern not yet federally listed as threatened or endangered, the tipping point birds are the highest priorities for science and conservation because of their "high vulnerability to extinction, high urgency, and steep population declines where known," according to the report. All are includedon the Birds of Conservation Concern List of the U.S. Fish and Wildlife Service and state lists of Species of Greatest Conservation Need.

"The tipping point species represent another 70 birds that could be next to face threatened or endangered status," the report states. "Cumulatively, the tipping point species that have sufficient data for monitoring have lost more than two-thirds of their populations in the past 50 years. Tipping point species come from varied habitats, but they all have the same urgency — immediate science and conservation actions are needed to turn around declines."

Faherty said most people think the "tipping point" saltmarsh sparrow is "on the path to gradual extinction" as the salt marshes they breed in drown due to sea level rise resulting from global warming, paired with development of the adjacent uplands, which prevents marsh migration and starves the marsh surface of sediment.

But that won't happen if scientists and conservationists have anything to do with it. There are already ongoing efforts to save this dainty bird that nests close to the waterline, Faherty said.

"Mass Audubon and others are working to restore marshes and protect areas that allow for marsh migration with sea level rise," he said.

The US Fish and Wildlife Service recently released an analysis of priority marshes for saltmarsh sparrows, including the marshes at Wellfleet Bay sanctuary and the Great Marshes of Barnstable.

The populations of the "tipping point" whimbrel and Hudsonian godwit, Arctic-nesting, migratory shorebirds, have both noticeably plummeted, Faherty said, noting "we see fewer passing through the typical shorebird hotspots here on Cape Cod compared with decades past despite there still being plenty of resources for them."

Whimbrels eat fiddler crabs, which he said are "super abundant" in local saltmarshes, when they pass through the Cape in late summer and early fall. The bird's traditional roosting areas are protected as well.

The issues these migratory birds face are more present in their breeding grounds in the Arctic, Faherty said, "but overall we could do a much better job on Cape Cod providing disturbance-free roosting areas for migratory shorebirds to rest, including semipalmated sandpiper and ruddy turnstone, which are also on the tipping point list."

Diminutive Prairie warblers, another of the "tipping point" birds, do well on the Cape in open areas with cedars, like powerlines and dunes, Faherty said, but are "almost certainly declining as open shrubby areas either grow into forest or housing developments."

Cape Cod's other "tipping point" bird, the least tern, benefits from concerted conservation efforts on the Cape.

"Our program contributes to monitoring least tern breeding on our beaches," said Geoff Sanders, chief of natural resource management and science for the Cape Cod National Seashore.

The Seashore works with other federal agencies, most notably the US Fish and Wildlife Service and United States Geological Survey, and local partners to conserve the birds under the requirements of the Endangered Species Act and other laws, policies, and regulations.

Mass Audubon is involved in conservation of vulnerable, beach-nesting birds like the least tern, as well, making a difference by protecting the birds from off road vehicles and other invasions by humans into their nesting areas. As a result, Faherty said the least tern is displaying an increasing trend in Massachusetts, though the success comes with a caveat — like other shorebirds, including the piping plover and American oystercatcher, the least tern remains vulnerable to the effects of climate change.

"They're vulnerable just because of where they nest and what's happening with erosion and more frequent storms," he said. "The way we see climate change playing out here, they are at risk going forward."

According to the Seashore, least tern breeding pairs were up in 2021, with 270 pairs observed in the park at 17 nest colonies. This was the most observed since 2004, the Seashore reports; however, only 24 chicks fledged, which equates to an average productivity of only 0.09 chicks per pair, the lowest number since 2015 — a decline in productivity that continues a trend seen over the past few years.

Shorebirds, facing loss of habitat as a result of rising sea levels, erosion and environmental degradation, are among the most impacted of the birds highlighted in the State of the Birds report. One third of shorebirds — 10 species — have experienced cumulative population losses exceeding 70% since 1980, the report reveals.

"Many shorebirds make epic long-distance migrations, flying thousands of miles between Arctic breeding grounds and South American wintering areas — and encountering threats throughout the western hemisphere," the report states. "Shorebird populations are down significantly in the last 40 years. Threats include disturbance and loss of stopover habitat along coastal beaches and estuaries, unregulated hunting in the Caribbean and South America, and continued draining of shallow wetlands."

Cape Cod's other birds of concern

The ground-nesting eastern whip-poor-will, one of the birds of concern listed in the report but not included in the "tipping point" sub-group, has declined drastically on the Cape. Faherty said this is due to fire suppression and development, "which includes the increase in nest predators associated with human development, like raccoons, foxes, and skunks."

This bird, however, still does well at Camp Edwards in Falmouth, he noted, "due to active habitat manage — forest clearing and prescribed burning — and is "also hanging on in Cape Cod National Seashore pine barrens."

Another bird of concern on the list, the snowy owl, may be seen on the Cape in the winter. Faherty said they are present "in widely varying numbers that correspond with lemming population outbreaks in Arctic Quebec, where our birds seem to breed."

"Cape Cod is not especially important to snowy owl populations, as only a few winter here," he said, pointing out that the threats to these birds are due to climate change impacts in the Arctic, where warming and environmental change is more severe.

The black-billed cuckoo is also on the birds of concern list, and its numbers, too, are declining in Massachusetts and on Cape Cod "as young, shrubby forests grow into more mature forests or housing developments," Faherty said.

And then there are the grassland birds — species like grasshopper sparrow, upland sandpiper, eastern meadowlark, and American kestrel — which are are all rare and declining in Massachusetts, but are not on the continental “tipping point” list. According to the "State of the Birds" report, grasslands bird species are the most impacted land birds — with a 34% loss since 1970.

"Here on Cape our grassland birds are hanging on at Camp Edwards and Crane Wildlife Management Area in Falmouth where biologists have removed trees and conducted prescribed burns to create and maintain the open, natural pine barrens and grasslands these species need," Faherty said.

Studying birdsThese seabirds are the harbingers of changing oceans. Studying them involves lots of poop.

Many of the 1,093 species of birds protected under the Migratory Bird Treaty Act are experiencing population declines "due to increased threats across the landscape," according to the U.S. Fish and Wildlife Service. Of those, 89 bird species are listed as either threatened or endangered under the  U.S. Endangered Species Act. An additional 342 species are listed as Birds of Conservation Concern, in one or more geographic areas — local, regional, or national.