New predator concerns for Monomoy

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The vanished break between South Beach and South Monomoy Island may be a bad break for nesting birds, especially the huge tern colony at the northern tip of the island.

Terns and other birds choose isolated islands for nesting so they’ll be safe from predators. South Monomoy Island was reconnected to the mainland during the Thanksgiving Day storm when the creeping sandbar from the south end of South Beach reached west to touch the tip of Monomoy.

As Michael Brady, director of the Monomoy National Wildlife Refuge pointed out, it is now possible to walk from Chatham Light (opposite the Coast Guard station) to Monomoy Light 15 miles away. And if a person can do it so can a coyote, fox, skunk, raccoon etc.

“Coyotes have been out there since the late ’90s,” said refuge biologist Monica Williams. “There are other small mammals out there. There was one raccoon in 2005 and maybe a skunk in early 2000. But for the most part the small mammals are not a major problem.”

That may not be the case come April, when the first piping plovers show up to nest.

“Generally, foxes are removed by coyotes that don’t let foxes [share] their home range,” Brady noted. “Skunks and weasels are a big problem on South Beach for plovers nesting out there. We’ve had, in the past, raccoons and possums. Skunks, weasels, possums and raccoons will be new critters we haven’t had to deal with before [on Monomoy].”

Any predatory animal can cause chaos in a colony of breeding terns.

“They prey on chicks and eggs,” Williams noted. “Just their presence, with the bigger mammals like coyotes and foxes, can cause the loss of an entire colony. They can go right through it and usually the birds will abandon their nests and leave. That happened in the late ’90s at a tern colony in Plymouth. A family of foxes out there caused a whole colony to be abandoned.”

“Common terns, roseate terns and least terns all are impacted by predators,” she added. “Roseate terns are federally endangered. Oystercatchers, black skimmers, all can be impacted by predators if they are not managed.”

The refuge, which also includes Nomans Island, was established in 1944 specifically to provide roosting, nesting and feeding habitat for migratory birds. Monomoy has connected and disconnected from the mainland in the past; as recently as 1958 it was connected before a storm broke it free.

The birds survived prior to the last break but it isn’t 1958 anymore. Massachusetts’ shoreline has been built up.

“It might be a good time to get organizations together to figure out if they can make a habitat for terns on Tern Island near the fish pier,” reflected Brian Harrington, a bird biologist with the Manomet Center for Conservation Science in Plymouth. “That was a major tern nesting island in the 1940s and ’50s but it required some management. It’s probably time to start strategizing to restore the value of Tern Island. The probability is that Monomoy will go down the tubes.”

That sounds dramatic but Harrington is well aware of the decimated Plymouth colony.

“Historically, terns in Massachusetts have shifted between Nauset Beach in Eastham, Tern Island, Monomoy and Plymouth Beach. When the going gets bad in one place they shift to another,” Harrington explained. “Plymouth Beach historically had 10,000 pairs nesting there.”

Last year 600 terns tried to breed there and “failed miserably,” according to Harrington.

That’s not the case on South Monomoy Island. Last summer 9,310 common terns nested on the island’s north tip, up from 8,834 in 2005 and they fledged 0.85 chicks per nest, a low number.  

While the federally threatened piping plover collects the most news clippings, the endangered roseate tern is actually in a more perilous position. Twenty-nine pairs nested in the refuge, 27 on ‘Minimoy’ Island and two on South Monomoy.

South Monomoy also welcomed 24 pairs of piping plovers, 57 pairs of least terns, 152 pairs of black crowned night herons, 13 pairs of oystercatchers while five pairs of black skimmers and eight pairs of oystercatchers resided on ‘Minimoy.’ North Monomoy Island also was home to nesting birds.

The tern colony is the largest on the Atlantic Coast but just 11 years ago it numbered only 300 pairs when the avian diversity program was implemented.  

“It started with bad PR,” Brady recalled. “I wasn’t here but that’s when they had the bird poisonings, but it was a desperate time. We were down to 300 pairs and there are no new sites.”

Gulls were poisoned because they eat tern eggs. Today laughing gull nests are destroyed to prevent them from overwhelming the terns.

“We don’t take that many anymore,” Brady said, “ten gulls, seven to eight night herons, six to seven coyotes a year. It’s not willy-nilly.”

But the potential for new troublemakers is high, including man and his best friend.

“We don’t mind people this time of year,” Brady said. “As long as they’re following the rules. The rules are strongly enforced in the refuge. Anyone can enjoy the refuge; it’s nice walking but there may be times it’s fully closed.”

South Beach is managed jointly by the National Park Service and the town of Chatham. Monomoy is under U.S. Fish and Wildlife control and hunting (on land), fires, dogs, unauthorized vehicles, metal detectors, feeding the animals – is not allowed.

“We don’t want dogs coming onto the refuge. They can do a lot of destruction in a short time in a tern colony,” Brady noted. “People take them (dogs) out by boat. They are already on South Beach.”

 

Dogs might be the easiest newcomers to cope with.

“It’s definitely a great concern for us,” Williams said. “We’re trying to put our heads together to brainstorm. We’ll see how things work out.”

The refuge has been dealing with some predators since the 1990s.

“We use a combination of techniques,” Brady said. “Coyotes are shot, gulls are removed. We also use harassment during nesting; black crowned night herons are shot.”

“It is very controversial but you have to remember there are not many islands they can nest on anymore because of habitat loss,” Williams added. “That’s why a place like Monomoy is very important.”

Hunters are not allowed in.

“We do all the active predator management in the refuge,” Brady explained. “We don’t outsource it. It’s managed in-house. But we don’t have the people and it will be a time-consuming thing.”

The coyotes are taken in the spring before they have pups. Other animals might be handled differently.

“A lot (of predators) come in for tuna so we may be able to Have-a-Heart them and remove them that way,” Brady speculated. “That may work for weasels, skunks or raccoons. Skunks are known nest predators but they are slow, they want to get out of the sun on the sand, so we may be able to track them down.”

“Twenty or thirty years ago skunks wouldn’t survive out there,” Harrington noted. “But they’re taking advantage of more garbage washing up on the wrack line.”

There’s no way to fence off all the nests.

“We have so many,” Williams said. “The tern colony is 10,000 pairs. They nest in groups in a colony, there is no way to put a barrier over the nest. The best we can do is manage the problem.”

While “Minimoy” (or the small spate of land to the west of South Monomoy) and North Monomoy are still islands, along with smaller sandbars, South Monomoy has been the prime real estate.

“The first birds get the good sites. The rest are left to go somewhere else,” Brady noted. “We’ll lose some birds for sure. There are no new islands being made in Massachusetts. They’ll have to go somewhere else. That’s a choice the terns will have to make. We don’t know what’s going to happen. We have no clue whatever.”

Monomoy has alternated between island, islands, and mainland status for centuries and will continue to do so but due to habitat loss, terns are no longer as resilient.

“In the short term there will be some definite impact but long term it will break through somewhere else and another island will form and the terns will come back,” Harrington said. “But the trend through the decades is one of decline. That will continue.”

If the terns do re-establish a colony on Tern Island they’ll be competing for food with seals.

The closed Southway Channel will reroute not only the seal-watching boats but possibly the seals themselves.

“The seals have already moved,” Harrington noted. “Last summer they were using the new inlet on Pleasant Bay, hauling out on the sand bars in big numbers.”

“The seals left the Southway,” Brady noted. “Their big food source is sand lances, or sand eels, and they headed up to the Chatham Fish Pier so the seals moved up too. They’re more visible now but the numbers are down. We had 5,000 to 6,000 two years ago. On the island we’re down to 1,500 and there are 500 to 600 at the Fish Pier.”

The seals breed on the southern tip of South Monomoy.

“We had four to five pups in January,” Brady noted.

The harbor and gray seals were collecting on the south tip of South Beach, which was cut off from Morris Island by the new isthmus. The seal-watching boats, at least some of them, will have to circle South Monomoy now if the seals stay oceanside.

“That’s a good trek, 30 minutes down and 30 minutes back,” Brady said. “The seals are in that area because they don’t want to be disturbed.”

The food source may also change and that could send them traveling again.

 “Things change as the plumbing changes,” Brady noted.