By Protecting Nesting Shorebirds, Monitors Help Maintain Beach Access
NORTH BEACH – Both the birds and their nests are difficult to spot, since they're the same color as the sand. And in the wide overwashes created by this winter's storms, there's a lot of territory to cover.
It's prime piping plover nesting season, and Assistant Conservation Agent Paul Wightman and Shorebird Monitor Tom Olson are spending a lot of time out on North Beach, scouring the sand for evidence of “scrapings” that indicate nesting activity. As of early this week, there were eight active nests on Chatham's section of the barrier beach and five more pairs getting ready to lay eggs. More pairs are expected to set up house in the next two weeks, according to Wightman.
Under a management plan approved by the conservation commission and state department of environmental protection, the town has had an active shorebird monitoring program on North Beach for several years. The plan and the monitors are required by the state if the town wants to continue to allow vehicles to access the beach. And Chatham's portion of North Beach – Nauset Beach before you cross the town line from Orleans – is perhaps the most popular spot on the spit. The wide, flat area created by the heavy surf that washed over the beach during the four northeasters that hit the area this winter will, in the coming weeks, be crowded with ORVs.
That is, if access remains open.
That's because those areas are also prime nesting habitat for plovers and least terns, both threatened species. And once the birds nest and the chicks hatch, vehicle access will likely be shut down for most of the barrier beach until the last baby plovers fledge. Wightman and Olson's job is to try to keep that period to a minimum.
For now, however, they walk carefully across the sand in search of the small indentations called “scrapings” that are the precursors of a plover nest.
“You've got to watch where you put your feet,” said Olson.
They peer through binoculars to spot the tiny sand-colored plovers and look for signs of nesting behavior.
Once four eggs have been laid in a nest, Wightman and Olson surround with an exclosure – wire pens with openings large enough for the plovers to scoot through but small enough to keep out avian predators like crows and kestrels. They have 15 minutes to erect the structure or the parents could abandon the nests; they've got it down to about five minutes. Motion-capture cameras track creatures that visit the exclosures.
The exclosures won't keep out a coyote – and there are plenty on the outer beach – but they have a strategy for that. Earlier in the season they put up three decoy exclosures wired to shock anything that touches them with 9,000 volts of electricity. Baiting them with salmon, sardines or dog food attracts the coyotes; their tracks can be seen circling the wire pen before there's a scuffing in the sand indicating where the animal touched the wire and was shocked.
“It hurts,” says Olson, who accidentally zapped himself once, but not enough to injure the animal. It is enough to modify their behavior, so that they will avoid the exclosures, especially those with nests, even though those are not electrified.
“If you don't see any tracks, you know you've done a good job,” Wightman noted.
The animals are clever, however. Wightman said one time a previously undetected four-egg nest was found too late in the day to put up an exclosure. When they returned the next day the eggs had just been destroyed. “We were maybe 10 minutes behind,” he said.
“The crows are the other big predator,” Wightman noted. “They'll pick off the chicks very easily.” To discourage crows from hanging around, nails are driven into all the posts that mark the vehicle trails so that the birds can't roost on them.
The plovers don't make protecting them easy. They tend to circle above nesting areas, and try to draw predators away from nests by behaving as if they have a broken wing – which will only interest a clever creature like a coyote. Within a few hours of hatching, the parents lead the chicks to the wrack line – the edge of the water – to feed on tiny insects, worms and crustaceans. They scuttle across the sand rather than flying. In some spots where the beach is narrow, there could be plover chicks running to both the inner and outer shore. That's why vehicles are prohibited in nesting areas during the fledging period.
Nesting areas are marked with symbolic fencing to warn beachgoers to stay away. While there may not be birds nesting within all of those areas, “they're probably going to be,” said Olson.
While the number of nests on North Beach last year paled in comparison to Monomoy Island – 16 as opposed to 48 – North Beach had better productivity, with 31 chicks fledging compared to 34 on Monomoy. Plovers also nested on North Beach Island, South Beach, Forest Beach, Harding's Beach and Ridgevale Beach. In Orleans there were nine pairs on Nauset Spit, producing 16 fledged chicks, and eight pairs on Nauset Beach South, fledging 27 chicks. Over the years, the number of nesting plovers in the state has remained fairly steady at between 600 and 700.
Officials will go to great lengths to protect both plover and tern nests, including relocating vehicle trails. Olson said one trail was moved to the west so it would be 100 yards from an area where terns are expected to nest (they've seen “scouts” but no nesting pairs yet). GPS coordinates for nests are recorded in a log book, as are the progress of nesting pairs, a requirement under the law. Once the first egg is produced, another comes every other day until the clutch reaches four, at which point both parents take turns incubating.
“They're not attached until they get four eggs,” said Wightman, meaning the birds are more likely to abandon the nest in the early stages. “Once we get four eggs on a nest we stay away from it. We use binoculars and we don't come up to it, we leave it alone.” By keeping careful records they can predict pretty accurately when the chicks will fledge.
Because the area they're covering is so vast, sometimes they miss nests and will suddenly see tiny hatchlings scuttling across the sand. “I call them bonus chicks,” Olson said.
If a nest is lost, breeding pairs will try to establish another within a week or two. Although the birds began nesting this season slightly later than usual, perhaps because of the cool weather, the goal of the monitoring program is to get the chicks hatched and fledged as early in the season as possible.
“The objective is to get the beach open as quickly as we can,” Wightman said.
Plovers return every year to the same area to nest, but this year “the whole geography, the morphology of the beach got wiped out” by the storms, said Wightman. From the southern tip of the beach north to the Chatham-Orleans line is “flat as pancake.” He suspects this year's numbers might be somewhat different because the birds may not recognize the beach and could move on to other nesting habitat, although because the changes essentially created the type of habitat the shorebirds favor, more pairs may be attracted here, he added.