Piping Plovers & Oystercatchers at Milford Point Help Themselves Survive

July 17, 2020 — The nesting season at the Milford Point Coastal Center was off to a rough start until early July. That’s when several things happened to turn it around, one of them quite amazing — three birds knew enough to protect their eggs from a tide that would have washed them away.

The other actions that helped were more routine. The Coastal Center parking lot was closed for the Fourth of July weekend, to keep people off the beach and sandspit. Additional fences went up to protect the birds. And vigilant (but friendly) staff and volunteers increased their patrols.

But the birds helped themselves. Two federally-threatened Piping Plovers and a state-threatened American Oystercatcher seem to have recognized that unusually high tides were on the way. The plovers moved their eggs to safer ground. The oystercatcher kept her eggs safe by sitting on them as the tide rose up her flanks.

Successful nests
The good news is that as of this week, there is one Piping Plover pair at Milford Point incubating in a wire exclosure — a cage that lets the birds come and go but helps stop raccoons, skunks, foxes, and other predators — and four plover pairs with chicks. Three of those pairs hatched within a three-day span. Eggs from a sixth nest hatched earlier.

Three pairs of American Oystercatchers have nested successfully too.

In early June, things didn’t look as good. Safety precautions because of the pandemic meant fewer monitors patrolling beaches and a temporary ban on the kind of close, cooperative work required to put up the protective cages. But those precautions have loosened.

This week Katerina Gillis, who works at Milford Point as a coastal ranger, was optimistic: “I’m glad we’re getting positive results after a rough start at the beginning of the season.”

The incoming tide
A good deal of the credit goes to the birds themselves.

High tides are always a risk, and the risk is growing greater as sea level rises. Before the Fourth of July weekend, a number of nests had already been washed away.

But after a particularly high tide, Kat noticed that a plover was incubating eggs outside of the protection of an exclosure. The day before, it had been inside the exclosure. This was the second nest of the season for that pair of plovers; the previous nest had been washed away by a high tide.

She and Patrick Comins, Connecticut Audubon’s executive director, also noticed that a plover in a different exclosure was incubating eggs in a different location within the exclosure from the day before.

Kat said that the tide definitely would have wiped out the eggs that had been moved out of the exclosure, and it came within an inch or two of the other eggs.

Rare behavior
Laura Saucier, a wildlife biologist with the state Department of Energy and Environmental Protection and a Piping Plover expert, said that moving eggs out of the way of the tides is not unheard of but is rare nonetheless.

“I’m not sure if it is a common behavior across all shorebirds but I suppose if you evolve to nest in dicey/dynamic places you have to roll with punches (or tides!).”

Over the same weekend, an incubating oystercatcher that had already had a nest destroyed by a predator, stayed put on her eggs as the tide rose around her.

Both eggs hatched and the young oystercatchers are alive.

Patrick Comins visited Milford Point numerous times from July 4th on to monitor the nests. These photos are the record of his official visits.