Biologists and birders hope their annual count will show increases in the number of piping plovers in Maine.

Thirty bird spotters combed 34 beaches for plovers and their nests as part of an international survey of the shorebirds Tuesday.

Piping plovers have been on the federal endangered species list since 1986. At last count, there were fewer than 100 in Maine, and 6,100 across the United States.

The birds migrate to Maine in the spring. They must nest by early July, since it takes chicks nearly 30 days to learn to fly, and plovers migrate to warmer points along the southern Atlantic coast and Gulf of Mexico in late summer.

Though a full clutch is four eggs, all eggs rarely survive. “We average about 1.5 chicks per pair,” said Catherine Caswell, a biologist with the Maine Audubon Society. “So they’re not even replacing each other right now.”

The International Piping Plover Survey involves the U.S., Canada, Mexico, the Caribbean Islands and France. It is held every five years. Maine does an annual count of its piping plovers, which begin to arrive in late March.

The survival of even a few chicks could reverse a downward trend in the state’s plover population since it reached a high of 58 pairs in 2002.

Biologists are putting their efforts into educating people about the birds that share beaches with vacationers, and they’re pleased with the cooperation so far.

Last summer, Ogunquit canceled a fireworks display that posed a threat to baby birds. Scarborough recently named the piping plover as its town bird.

And many towns are adopting leash laws to keep dogs from tromping through nesting areas.