Turtle Scene Investigation: How We Identify Nests

Blog Post By: Sarah Glover, Sea Turtle Intern

If you’ve been on our beach in the morning, you’ve probably seen our turtle team out patrolling the beach and marking nests. But how do we identify nests and find the eggs? Well, there are a few things we look at.
          
The first thing we observe are the tracks left by the turtle. We look for “v” shapes in the sand to figure out which track was her incoming and which was her outgoing. The “v” points in the direction in which the turtle came. For example, if it points to the ocean, then that is the path she took out of the water. Identifying her incoming and outgoing tracks allows us to determine which way the turtle was facing while she was laying her eggs.

Looking at the tracks also helps us to determine which species of sea turtle the crawl belongs to. Loggerhead sea turtles, the primary nesters on our beach,  move with alternating limb movements, which means they move one flipper at a time. Other species, such as the green sea turtles, move with parallel limb movements, moving both flippers at the same time and pulling themselves up.

The next thing we look for in our “turtle scene investigation” is thrown sand. Once the turtle has made her was up the beach and found a good spot, she begins to make a body pit by throwing sand with her front flippers. She may even tear up vegetation in this area. She then uses her back flippers to scoop sand and dig an 18–24-inch egg chamber. When she is finished laying her eggs, she will spend a lot of time covering them up. She throws lots of sand and pats it down with her full body weight to ensure they are well hidden. In other words, a lot of sand is thrown and moved around during the nesting process. If we see tracks leading to a body pit with thrown sand, there is a good chance that eggs are hidden below. However, if there is no body pit or if not much sand has been thrown, then the turtle may not have nested. This is what we call a false crawl.

​Finally, once we have identified that we are looking at a nest, we use a device called a probe to find exactly where the eggs are buried. There is an air pocket above the eggs in the chamber that we feel for. We push the probe into the sand and when we feel a slight drop, we know the eggs are buried below.