After decades of clamorous nesting birds on Seahorse Key, a 150-acre mangrove island off Florida's Gulf Coast, the birds have dramatically abandoned their nests. Some of them have relocated to another island, Snake Key, according to a University of Florida's Seahorse Key Marine Laboratory website update.
However, a biologist with the U.S. Fish and Wildlife Service, Vic Doig, told the Associated Press that the birds that moved to Snake Key are only a fraction of those that would normally be on Seahorse Key, according to the Associated Press.
Scientists became aware of the severe quiet in May on Seahorse Key.
The birds that normally nest here--little blue herons, roseate spoonbills, snowy egrets, pelicans and others--were gone. Nests sat empty in trees, according to a press release from the U.S. Fish and Wildlife Service (USFWS).
"It's a dead zone now," said Vic Doig, a USFWS biologist, according to the AP. "This is where the largest bird colony on the Gulf Coast of Florida used to be."
Seahorse Key has traditionally been a way station for bird species and it is part of the Cedar Keys National Wildlife Refuge, near Crystal River, Florida. It's accessible only by boat.
"It's not uncommon for birds to abandon nests," said Peter Frederick, a University of Florida wildlife biologist who has studied Florida's birds for nearly 30 years, according to the AP. "But, in this case, what's puzzling is that all of the species did it all at once."
In reaction, biologists took action: They tested left-behind bird carcasses for disease or contaminants. Their test results were negative. They found no telltale signs of new predators. They noted an increase in night flights over the area by surveillance planes and helicopters used to combat drug runners--but they think that disruption from the planes' noise is a longshot, says Doig, according to the AP.
Scientists are concerned about whether the abandonment could have a ripple effect: Is the island refuge lost? Will other animals on the key be affected by the birds' departure, they asked, according to the AP.
"Any rookery that's persisted for decades as one of the largest colonies is incredibly important," said Janell Brush, an avian researcher with the Florida Fish and Wildlife Conservation Commission, according to the AP. "It's quite a large colony. There had to be some intense event that would drive all these birds away."