WESTERLY — On a rocky beach below a row of Watch Hill mansions, a newborn bird scampers back and forth — a tiny puff of feathers on spindly legs. The bird is so young, it trips and staggers across dimples in the sand.

One of its parents follows a few feet away. As they make their way down the beach, they encounter another adult. An intense, albeit barely perceptible, confrontation of peeps and wing flapping erupts between the two adults before both back off.

Not long ago, it was difficult to find piping plovers in Rhode Island. Numbers of the migratory shore bird were so low, it was declared a threatened species under the federal Endangered Species Act. Now the birds have recovered so well, particularly at exclusive locations such as Watch Hill, that they are battling over territory.

A total of 61 pairs of plovers are nesting on Rhode Island beaches this summer — the highest number in years. Massachusetts is home to about 600 more nesting pairs.

In recent weeks, the bald eagle has been in the news because its numbers have risen so well it is being removed from the endangered species list. Less noticed has been the success story of the plovers. In the North Atlantic region, wildlife experts say they feel the plovers will have recovered when the number of nesting pairs reaches 2,000. It has climbed to about 1,600 pairs so far.

Twenty years ago, the decision to save the birds sparked some of Rhode Island’s most intense and emotional battles over its coastline.

In 1987, there were just two nesting pairs of plovers and a diminished population of least terns, another shore bird. The plovers laid eight eggs, but all were destroyed by predators attracted to the refuse left behind by beachgoers, according to the manager of a nearby federal wildlife refuge.

The U.S. Fish & Wildlife Service cited both birds when it proposed closing Moonstone Beach from April to August. At that point, about a third of the beach was leased by South Kingstown for its Town Beach, another third was a nesting area for the birds, and the last third was used by nudists.

Initially, the closure was to be for one year.

The town responded by buying private property to the east, near Matunuck Beach Road. The nudists, who felt they were being unfairly targeted as a solution to the plovers’ plight, went to court.

Some critics predicted the plovers were doomed no matter what the government did. One said herring gulls were killing the plovers. Many were unhappy to lose their beach to a few birds.

But the next year, the number of nesting pairs doubled to four.

A judge turned down the nudists. But they kept going to the beach and sitting on the sand between the bird fencing and water until 1990, when the Fish and Wildlife Service announced it was closing the entire beach because the plovers were having trouble feeding at their favorite places, the water’s edge.

The birds kept doing better and better. In 1991, biologists said the number of least tern pairs rose to 50, compared with just 4 in 1989. Nineteen piping plover chicks were born, compared with none in 1987.

In 1991, a federal magistrate ruled in favor of a lawyer who was arrested for running on a stretch of beach marked off for the plovers. The magistrate dismissed the trespassing charge, saying the Rhode Island Constitution gives people the right of passage between the low and high water marks on the shore.

In 1997, someone drove around a locked gate at East Beach in Watch Hill and crushed a nest with four baby birds. The next day biologists found the two parents trying to pick up and revive their lost brood.

In 2003, someone illegally drove onto a South County beach, crushed one adult bird and destroyed fencing and signs set up to protect another pair, which survived.

Still, the number of plovers grew.

On the beaches, it is difficult to spot plovers because their coloring helps them blend in with the sand and stones. They often nest near the terns, which respond aggressively to intruders, with alarm calls and sweeping flights.

But so far this year, the fish and wildlife biologists have identified 61 nesting pairs of plovers, up 3 from last year, and at least 105 nesting pairs of terns. The Nature Conservancy is monitoring 12 additional pairs of plovers in Little Compton.

It’s been a challenging year, says Wendy Edwards, a Fish and Wildlife Service biologist who works with 5 staff members and 50 volunteers to monitor and protect the plovers.

The spring northeaster gouged the beaches and forced many of the birds to build new nests.

Now, the birds are nesting, and the question is how many of the young will survive. It takes 28 days on average before chicks can fly. Until then, they scamper back and forth, eating insects on the beach.

Broad areas of the beach are roped off to keep people away, and the nests are surrounded with fencing to keep out predators.

Each pair typically lays 3 or 4 eggs, but Edwards said biologists would be happy if an average of 1.5 birds fledge from each pair of parents.

The hot spot in Rhode Island is Watch Hill. All the no-parking signs around the mansions leave long stretches of beach quiet. The adults also like the pond behind the beach as an alternative place to feed.

There are 18 nesting pairs on East Beach and another 6 just to the west at Napatree Point. One pair is nesting at East Matunuck and one at the Narrow River. Eight pairs are nesting at the quiet beaches at Ninigret Conservation Area and another 7 at the Ninigret National Wildlife Refuge. There are 7 pairs in Quonochontaug, 10 at the Trustom Pond National Wildlife Refuge, and 1 each at Third Beach and at Sachuest Point National Wildlife Refuge. Another pair just got together on Block Island.

The Nature Conservancy oversees 7 nesting pairs at Goosewing Beach and 5 pairs at Briggs Beach.

This year the conservancy lost a number of nests to high tides, according to preserves manager Cheryl Wiitala. It’s also seeing many young birds lost to predators and disturbances caused by dogs and people.

At least public reaction to the plovers seems to have changed, Edwards says. “A lot of people like to come out and enjoy the birds. Hopefully, we’re adding to their experiences. My main goal is to balance human and bird needs.”

When observers got too close to a nesting plover at East Beach last week, he or she (the parents alternate) ran away from the nest and flopped on its side with its wing spread, as if it were broken.

It flopped around for about a minute, and then dutifully returned to the nest and sat back down on the eggs, trying to blend into the beach.

plord@projo.com