TTOR steps up predator control to protect nesting shorebirds

The implementation of a controversial predator-management control method on Martha’s Vineyard beaches has proven successful.

A sign posted on Norton Point Beach alerts vehicle drivers to stay out of a tern nesting area. — Photo by Catey McCann

Each summer season, The Trustees of Reservations (TTOR), a nonprofit conservation organization that manages miles of pristine beachfront on Chappaquiddick open to the public and accessible by over-sand vehicles (OSV), gears up for the arrival of state and federally protected shorebirds that seek out the gravel and sand of Martha’s Vineyard’s shoreline to nest and lay eggs.

Overall, TTOR has been successful protecting the birds against human intrusion. Beach closures that prohibit vehicles and in some cases people are put in place when warranted by nesting activity. The major threat is natural predation.

This season, TTOR has initiated a program under the close watch of federal authorities to control an animal known for its intelligence and ability to gobble up eggs and newly hatched chicks — the crow.

Mandated protection

Chris Kennedy, TTOR Martha’s Vineyard superintendent, explained that state and federal law mandates protection for shorebirds, particularly where vehicles are to be allowed on a beach. The Vineyard hosts three species of protected birds. Terns are a species of special concern and are at the lowest threat level, piping plovers are a threatened shorebird and are at a higher level of concern, and roseate terns are considered endangered.

There are generally 12 to 20 pairs of plovers found nesting anywhere on Chappaquiddick beaches, and from 500 to 3,500 nesting terns at Norton Point, the barrier beach that connects Katama to Chappaquiddick. Those significant numbers require substantial protection efforts from TTOR.

By April 1 of each year, TTOR marks off areas where the birds traditionally nest. A good portion of Leland Beach, for example, is marked off and off-limits to vehicles.

In April and May, the birds return and begin to nest and lay eggs. The eggs then incubate for three weeks to a month — oftentimes until May or June. Once the birds begin to nest and lay eggs eggs in June, a whole different level of protection is put in place until the birds are able to fly. This can include so-called exclosures, cages of chicken wire placed over a nest to keep out predators.

It takes about another four weeks until the chicks have fledged. Only at that point are vehicles and pedestrians allowed back into closed areas.

“We understand that if someone is hell-bent on breaking through the fence and driving through an area that’s closed off for shorebirds, then they’re going to do it,” Mr. Kennedy said. “But the consequences of doing that are pretty hefty. I think most people realize that’s just not something that you do.”

Mr. Kennedy said that vehicles are no longer the major threat, however.

“At this point, I would say the predators are the major threat,” Mr. Kennedy said. “If you had asked me that question 20 years ago, I might have said it was really a tossup between vehicles and predators. Now that vehicles have been controlled, they really do not pose an active threat to the shorebirds, because we keep them away from the chicks as well as the nests.”

Smart and dumb

Mr. Kennedy said there are two main types of predators that shorebirds face on the Island — smart and dumb.

“Crows are an incredibly intelligent bird, and there are some that will recognize that these exclosures that we put up around the nest potentially contain food,” Mr. Kennedy said.

He said the crows will perch right on the exclosures and harass the adult shorebirds until they abandon the nest, leaving behind eggs for the crow to consume. It’s a Catch-22 when the protection put up to aid the nesting birds becomes their biggest threat, essentially acting as a big, flashing “there’s food here” sign for the predator crows.

“You basically have to keep a close eye on those exclosures, and the first option we usually use if we find that there is a crow or a gull or some other predator that’s keying in on that exclosure, we’ll just take it down,” Mr. Kennedy said.

Which leaves the nests vulnerable to the “dumb” predators: skunks.

“When crows are really smart, skunks use the really dumb approach,” Mr. Kennedy said. “They just walk back and forth until they eventually find the eggs.”

Too smart

For the past several years, TTOR utilized box traps for both skunks and crows. This year, TTOR implemented a more controversial antipredation tactic, lethal crow control. Although they don’t like using this method, TTOR ecology assistant Caitlin Borck said it is necessary.

“We don’t like to do the lethal control,” she said. “It’s been after decades of passive management that we’ve resorted to doing lethal predator management.”

In conjunction with the U.S. Department of Agriculture, TTOR put up mock exclosures to attract the intelligent birds.

“The thing is that crows are very smart, and they will teach other crows their behaviors,” Ms. Borck said. “If we were not to remove these smart predators from our property, they would continue to teach other crows more and more that exclosures are a food source.”

TTOR wants to remove the intelligent crows from the property so that no new crows will learn the behavior. In order to do this, chicken eggs are put in the mock exclosures for two weeks and cameras monitor for crows that are targeting the exclosures. Once identified, with USDA approval, TTOR places toxic eggs in the exclosure.

Ms. Borck said it’s a very pointed approach, and removes only the predators targeting exclosures.

“And that has been working very well,” Ms. Borck said. “We haven’t seen too much crow harassment, and we’ve seen a decrease in the population around our nesting areas.”

She said that after implementing this strategy, TTOR lost only two nests to depredation this year, which is considered a success. But not everyone is fond of this method. Ms. Borck said there has been some opposition.

“Crows are very intelligent, and people love crows because of that,” she said. “A lot of people have an affinity with crows, so not everybody is happy with this method.”

However, Ms. Borck said that lethal antipredation is becoming an increasingly popular method with other organizations. “There’s already at least 15 either government, municipal, or private organizations that are using this method,” she said. “And next year it will likely be more, so it’s becoming more and more popular.”

The mock exclosures are only used early in the season to target the crows. All the current exclosures on the beaches are being utilized for shorebird and egg protection. Ms. Borck said the hope is that the lethal control method is not something TTOR will have to consistently utilize.

“It will go in cycles because once we stop doing this, some crow will figure it out and start teaching again,” she said. “But we won’t have to do this constant predator management.”

Mr. Kennedy said that TTOR also runs a very active skunk-trapping program during the most vulnerable periods of the summer, usually in the spring and early summer when the skunks are out and actively trying to feed.

“There’s no easy solution here,” Mr. Kennedy said. “On one hand you have animals that have a place in the natural world – whether it’s a skunk or a crow – what we’re trying to do is just remove those predators that pose the greatest threat to the nesting shorebirds.”

Frustrated beachgoers

“People definitely don’t understand why we have to close the beaches,” Ms. Borck said. “They don’t understand how small the birds are. They want to fish, they want to enjoy the beach; they spend a lot of money on passes to come out with their vehicle, and we do warn people about that, but it’s still very frustrating for them.”

She said TTOR understands the frustration, but has to follow federal and state guidelines regardless. As a result, Ms. Borck and two other shorebird technicians are out monitoring the beaches by 7:30 am every day for four to 12 hours a day. They watch for birds, look for new nests, count eggs, look for tracks, put up exclosures, and enforce beach rules.

Mr. Kennedy said TTOR can spend between $70,000 to $100,000 per year for protection efforts. That includes staffing, equipping the staff with vehicles, materials, fencing, and signage.

“The costs are significant,” Mr. Kennedy said. “It’s not a cheap endeavor to do.”

But, he said, the only other option is not to allow vehicles access to the beach at all. Given that many beach areas are not within walking distance, Mr. Kennedy said it’s not realistic to expect people to walk.

He said that in general people are compliant with the protection, although many are unhappy. In an effort to engage with the public, TTOR conducts guided shorebird tours that are increasingly popular.

“It shows me there’s that opportunity to teach people who aren’t getting that information,” Ms. Borck said. “They’re only getting the information that the beach is closed and you can’t come out: the upsetting part. They don’t get the details of why, and when they do, they’re actually pretty understanding.”

Mr. Kennedy said public compliance with the rules has helped TTOR meet or exceed a target nesting success rate of 1.5 chicks per nest.

“A lot of that success is because we get a lot of cooperation from people,” Mr. Kennedy said. “When they see the signage or they see the fencing, they avoid those areas. They don’t let their dogs run loose. If they have to walk from point A to point B and it’s through shorebird area, they walk right down close to the water.”

The birds have nested uncommonly early this season due to successful predator protection and a lack of any major storms. Mr. Kennedy said he hopes that will mean an early reopening of areas now closed off.

“The hope is that if these birds can escape any major storms or any sort of predation or being run over by vehicles, these little chicks will fledge in approximately a month, which will bring us to the first week of July,” Mr. Kennedy said. “Hopefully at that point, most of these chicks will have fledged, and we can open up most of the beaches for the better part of the summer.”