Bird Exodus En Mass Off Of Florida Island; Leaving Eggs Behind

A broken egg sits in one of the empty nests on Seahorse Key. Biologists do not know how the disappearance of the birds will affect other wildlife that depend on them.

SEAHORSE KEY — The din created by thousands of nesting birds is usually the first thing you notice about Seahorse Key, a 150-acre mangrove-covered dune off Florida’s Gulf Coast near Cedar Key and Sumner.

Thousands of little blue herons, roseate spoonbills, snowy egrets, pelicans and other chattering birds were gone. Nests sat empty in trees; eggs broken and scattered on the muddy ground.

“It’s a dead zone now,” said Vic Doig, a U.S. Fish and Wildlife Service biologist. “This is where the largest bird colony on the Gulf Coast of Florida used to be.”

For decades, Seahorse Key has been a protected way station for myriad bird species. It’s part of the Cedar Keys National Wildlife Refuge, about 21 miles west northwest of Crystal River, established in 1929 as a sanctuary for birds devastated by decades of hunting for their colorful plumage. Accessible only by boat, today it’s a rare island not dominated by human activity and development.

In this Friday, June 19, 2015 photo, a roseate spoonbill flies near Snake Key, short distance from Seahorse Key, off Florida’s Gulf Coast. In May, Seahorse Key fell eerily quiet, as thousands of birds suddenly disappeared, and biologists are trying to find the reason why. U.S. Fish and Wildlife Service biologist Vic Doig said what was once the largest bird colony on the state’s Gulf Coast is now a “dead zone.”   (AP Photo/John Raoux) FLJR108

When the birds come to nest, so too do biologists and naturalists who study the different colonies. But this year, the birds’ exit has the state’s avian biologists scrambling for answers.

“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. “But, in this case, what’s puzzling is that all of the species did it all at once.”

Doig said some of the Seahorse birds seem to have moved to a nearby island, but they’re just a fraction of the tens of thousands of birds that would normally be nesting on the key right now.

To find answers, service biologists have been acting on the few clues they have.

First, they tested left-behind bird carcasses for disease or contaminants. Those tests came back negative.

Larry Woodward, left, and Vic Doig of the U.S. Fish and Wildlife Service look for birds off the shore of Snake Key. In May, nearby Seahorse Key fell eerily quiet, as thousands of birds suddenly disappeared, and biologists are trying to find the reason why. Doig said what was once the largest bird colony on the state's Gulf Coast is now a "dead zone." [Associated Press]

Next, they researched possible new predators. Did raccoons swim over from another island? Perhaps some great horned owls flew out at night and started feasting?

Traps caught a few raccoons, which is common, but not enough to have created a wholesale abandonment. There were no telltale signs of owls.

Finally, Doig said, recent years have seen an increase in night flights over the area by surveillance planes and helicopters used to combat drug runners. Although the planes’ noise could be disruptive, Doig admits it’s a longshot.

The abandonment concerns biologists because it could have a ripple effect: Many bird species here return year after year to the same nesting sites. The disruption provokes anxiety that this important island refuge could somehow be lost.

“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. “It’s quite a large colony. There had to be some intense event that would drive all these birds away.”

Biologists also don’t know how the disappearance will affect the island’s other animals, some of which rely on the birds to survive. Cottonmouth snakes eat bird predators like rodents, and in turn the birds drop lots of fish and other nutrients from the trees to feed the snakes.

Vic Doig, a U.S. Fish and Wildlife Service biologist, observes empty bird nests on Seahorse Key after the area went quiet in May. Doig said the key once housed the largest bird colony on the Gulf Coast and included the three species pictured above.

In the meantime, tour operators that once spent hours taking naturalists and bird watchers to the island are making other plans.

Mike O’Dell runs tours out of the little marina in Cedar Key. He said that on a Tuesday in May, he led a group out to view thousands of birds crowding the shores of the key. On Wednesday, there was nothing.

“It’s just that drastic,” O’Dell said. “There were none. It’s like a different world.”

Original Article: http://www.tampabay.com/news/environment/wildlife/thousands-of-birds-abandon-eggs-nests-on-floridas-seahorse-key/2236425

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.