IPSWICH — Anyone who has been to the beach more than once is familiar with the drill. As the moon works its magic and the ocean begins its slow crawl up the sand, blanket after blanket gets moved to higher ground.
This migration isn't a problem for much of the year, but between mid-July and mid-September it can interfere with another migration that is about more than just staying dry.
The Trustees of Reservations have instituted a new policy that prohibits spreading a towel on some parts of Crane Beach at high tide. The goal is to keep beachgoers away from the thousands of migratory birds that rest on the beach at high tide, when they can't forage in the Great Marsh behind the barrier beach.
Ropes with buoys attached have been laid out in the affected areas, with signs advising that if the buoy is wet — picked up by the incoming tide — the area should be treated as a "No blanket zone."
Similar signs are attached to the buoys.
Franz Ingelfinger, an ecologist at the Crane Reservation, said resting spots known as staging areas are critical as migratory birds prepare for their lengthy and exhausting flights south to their winter grounds.
"They need the time to rest and refuel," Ingelfinger said.
The most common migratory birds at Crane Beach are sanderlings and semipalmated plovers and sandpipers.
Semipalmated plovers are declining at the rate of 4 percent of the species every year, Ingelfinger said.
"In 18 years, they'll be half what they are now," he said.
About 80 percent of the birds that use the beach as a way station occupy a quarter-mile stretch of sand about 1 mile east of the boardwalks. With 41âÑ2 total miles of beach, there's no reason for sun worshippers to interfere with the birds, Ingelfinger said.
"They're still welcome to walk by and enjoy them, by all means," he said. "Just don't disturb them.
The Trustees rolled out this new program this summer, and Ingelfinger said it's been well-received by visitors.
It's no big deal for you to pick up your blanket and plunk it down somewhere else, but the birds aren't so fortunate.
"They don't have anyplace else to go," Ingelfinger said.