In scenes completely opposite to those depicted in the classic Hitchcock movie The Birds, areas once densely populated by birds on Florida's Gulf Coast are eerily avian free.
Seahorse Key, a 150-acre mangrove-covered dune off Florida's Gulf Coast that up to a few months ago was the habitat for many bird species, has hardly seen any bird life since May .
U.S. Fish and Wildlife Service biologist Vic Doig said "It's a dead zone now. This is where the largest bird colony on the Gulf Coast of Florida used to be."
The thousands of thousands of pelicans, blue herons,snowy egrets, roseate spoonbills and other bird species are gone, tree nests sit empty and eggs lie broken and scattered on the ground.
Doig said some Seahorse birds have moved in to a nearby island, but their numbers are a mere fraction of the number of birds that would normally be nesting on the key this time of year.
Seahorse Key, a protected way station for migrating birds, accessible only by boat, is part of the Cedar Keys National Wildlife Refuge which was set up in 1929 to offer protection for species of birds which were being wiped out by hunters who were after their colorful plumage.
Peter Frederick, a University of Florida wildlife biologist said "It's not uncommon for birds to abandon nests but in this case, what's puzzling is that all of the species did it all at once."
Like a SCI unit, biologists have been following up on the few clues that have been left behind - testing bird carcasses for contaminants or disease or contaminants but all test so far have come back negative. Searches for possible predators have also come up empty.
Some had thought increases in night flights by drug runner surveillance helicopters and planes may be to blame but Doig said that was a "long shot".
Janell Brush, a Florida Fish and Wildlife Conservation Commission avian researcher said "It's quite a large colony. There had to be some intense event that would drive all these birds away."
What worries biologists most is the possibility that the bird disappearance may be the beginning of a ripple effect. They are unsure how bird disappearances will affect the island's other animals as they were part of the area's food cycle.
They site the example of Cottonmouth snakes which eat bird predators like rodents with their payback being the birds dropping fish and other nutrients from trees for them to eat.
There is also a commercial implication from the bird disappearance. Tour operators that usually take bird watchers and naturalists to the island suddenly have to find another source of revenue.
Mike O'Dell who operates tours for birders from nearby Cedar Key said in May there were thousands of birds but on a recent visit to the area he had seen virtually zero.
"It's just that drastic. There were none. It's like a different world."