The Diamondback Terrapin Nesting Survey

2009 Flyer coming soon

This year's survey was very successful! We will be posting a photo essay and data soon.

Diamondback Terrapins are the only salt water turtle which is indigenous to our saltmarsh habitats. Unlike the larger sea turtles which migrate great distances during the year, the Diamondback Terrapin spends its entire lifecycle laying, hatching and hibernating in the same saltmarsh. Once valued as a human food source, they are now considered a threatened species. We study these turtles in Flax Pond and at West Meadow Beach as part of an Island- wide effort conducted by researchers Russell Burke at Hofstra College and Matt Draud at CW Post, who track turtle populations and learn about their behavior.

The Diamondback Terrapin Nesting Survey begins at the end of May and continues through the end of July. Like the Horseshoe Crab Spawning Survey, the terrapins nest on a lunar cycle and at high tides. Under the supervision of Dr. Matthew Draud from CW Post, Long Island University, the Friends of Flax Pond recruits community members to become citizen scientists and help in the survey.

2006 was the first year we conducted the Diamondback Terrapin Survey at West Meadow Beach and Flax Pond. We were able, as a result of walking the beaches during the nesting cycle, to determine where, at both sites, the turtles are most likely to nest. We also learned more about when the turtles are most likely to appear and how to coordinate accordingly. We were particularly helped in 2006 by a volunteer who attended our workshop and called to alert us one morning, after an early bike ride at West Meadow Beach at high tide, that turtles were arriving. Matt Draud, who also does research at Oyster Bay and other Long Island beaches, had shared with us that when turtles arrive at one beach, they often tend to arrive at others on the same day. This proved to be the case in June ‘06 when we were able to identify and mark turtle nests at West Meadow Beach and Flax Pond on the same day.

Female turtles swim ashore on the high tide and then nest in the High Marsh. Their eggs have been fertilized by encounter with the smaller males in the water prior to laying. Females Diamondbacks, like other sea turtles, tend to return year after year to the same beach for nesting.

Once the terrapins begin to arrive, we notify Dr Draud for supervision and our citizen scientist volunteers go to work under the direction of one of our Volunteer Coordinators. There are several steps to the scientifically designed survey, as follows. This is a general description for general information, but which excludes scientific details.

1. This first step is perhaps the most important because it involves observing the turtle without the turtle's awareness of being observed. Diamondbacks have been known to continue their nesting activity if unnoticed or ignored by passersby. However, the terrapins are hyperaware of the potential presence of perpetrators and have a keen sense of when they are watched, often stopping in the middle of digging a nest and moving off to another location. As a result, "test nests", disturbances in the sediments, can be identified at nesting sites. Once the eggs are laid, the terrapin covers the nest so carefully it can be impossible to identify. Thus the scientist observing a nesting turtle must remain hidden from the turtle's awareness but also be alert to the moment she has finished covering her nest.

   

   A Turtle Covers A New Nest
   Click for a larger version

2. The next step is to very quickly approach the nest before the turtle has left it (or it may be otherwise difficult to impossible to find), and mark it with a flag.

   

   A Turtle By A Flagged Nest
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3. Then catch the terrapin who is now setting off back to the water she came from, weigh, measure, and record her data on a sheet numbered to correspond with the number assigned the nest flag.

   

   Volunteers Receive Instuctions On Recording Turtles
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4. After releasing the turtle, some nests are protected by a wire cage to try to prevent predation, most likely by raccoon. Recent studies have indicated that cages alert predators to nest locations. This year, not all nests were caged to try and prevent this conditioning.

When nests are predated, it is possible afterwards to find turtle eggshells scattered about the excavated nest. In this fashion, new nesting sites in can be identified. Late in the season 2006, a predated nest identified a new site for researchers. A protected nest at another site in Flax Pond was not predated. Four caged nests at West Meadow beach were also protected from predation.

If you wish to participate, email us at flaxpondfriends@gmail.com