Video cameras to spy on sea turtles during nesting

9:28 AM, May 16, 2011   |    comments
File photo of a loggerhead -- photographed with Florida wildlife officials' guidelines -- lays its eggs in the sand of a Brevard County beach.
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Melbourne Beach, Florida (FL Today) -- Hidden cameras soon will shed light on what makes mother sea turtles give up on nighttime nesting attempts on the beach.

Brevard County Environmentally Endangered Lands Program plans to use a novel time-lapse photography technique to spy on the female sea turtles this summer at the Barrier Island Sanctuary in Archie Carr National Wildlife Refuge.

EEL received an $8,380 grant from Florida's sea turtle specialty license plate revenue to put three hidden cameras along 1,000 feet of beach, well out of the way of nesting turtles.

They want to know what makes turtles abandon nesting, and especially whether the sanctuary's guided nighttime turtle walks alter nesting behavior in any way.

When sea turtles throw in the towel on nesting attempts, they tend to dump their 100 or so eggs at sea, biologists say. And every egg counts, given that only 1 in every 1,000 hatched turtles dodges predators, disease and other threats long enough to reach adulthood.

Flashlights and flashbulb cameras can cause "false crawls," where the turtles return to the ocean before laying eggs on the beach. So the three cameras for the study won't use flashes.

"It's been difficult to quantify those false crawls," said Ray Mojica, a manager at Barrier Island Sanctuary. "We think we can get some real strong data from that section of beach."

The 61-day study period will coincide with the sanctuary's June and July guided sea turtle walks.

Biologists prefer people go on structured turtle walks, led by state-permitted guides. But many venture out on their own, using flashlights that can disturb turtle nesting.

EEL staff plan to create a database of "false crawl" hotspots, linking them with the preceding night's imagery to see what may have caused the false crawls. The cameras will take images at several-second intervals, documenting when raccoons, bobcats or other predators dig up and eat turtle eggs.

The turtle-time-lapse idea came from James Schubert, a volunteer at the Barrier Island Center and camera enthusiast who gleaned the time-lapse technique from astrophotography methods.

Last summer, he and EEL staff tested long-exposure, light-sensitive cameras to capture images of nesting turtles, raccoons rummaging around and nighttime beach walkers.

Lenses with unusually large apertures let in the maximum amount of light to create images that look as if taken during the day.

According to the grant proposal, EEL will make a video summation of "the most egregious cases of human turtle interactions" and show a short documentary about the time-lapse study in the Barrier Island Center auditorium.

Jim Waymer, Florida Today

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