Kiley BriggsViews:
While adult turtles have very high survival rates from year to year and can live exceptionally long times, the life expectancy of a hatchling is very short. Indeed, most turtle nests don’t survive (nest failure rates are often greater than 90%), and out of the small percentage of hatchlings that do make it to the surface, the odds are not good during their first year of life. With soft shells offering minimal protection, almost every predator out there would happily eat any hatchling turtle they find, which comparatively speaking, are like little savory Oreos scuttling across the landscape. Raccoons, foxes, skunks, and mink are the usual suspects, but the list of potential hatchling predators is very long and also includes some unsuspecting species like American Crows, Ravens, and even chipmunks (at least one study found that most Blanding’s Turtle hatchlings were eaten by chipmunks before the turtles ever made it to the water). That is why when we began monitoring Wood Turtle nesting habitat last year, we were VERY surprised with what we found.
Out of the 10+ nests we monitored, every single one hatched. In fact, we were unable to even find evidence of predation at any of three separate nest sites. Predators are usually pretty good at finding turtle nesting habitat, and the more turtles that nest there the more likely it is predators will find it, but even the site with the highest concentration of nests had zero eggshells on the surface (eggshells remain for at least a year or so and when they are exposed on the surface that is an indication that a predator dug them up). This was especially surprising because not only is there human recreation on-site (which can attract predators), but the spot also has relatively low numbers of juvenile turtles, hinting at nesting or recruitment problems.
A common method used by conservation biologists to protect turtle nests from elevated levels of predation is temporary electric fencing and placing protective caging around the nests themselves (with a way out for the turtles, of course). I have been asked many times if we plan to protect nests at this site in the future, and a year ago I would have said that would be a likely priority moving forward, but first we needed to find out if predation was a concern. Now I would say that fencing off the site would be a waste of time and resources that would be better spent on efforts to improve the quality of the site through habitat management. Ideally, conservation efforts should address site-specific conservation threats, and in this case a much more imminent threat to Wood Turtle nests at that location is succession, not predation.
The most critical nesting site at this location is almost gone. Located in upland habitat on a steep east-facing hill about 200-feet from the stream the turtles overwinter in, the open patch of sandy soils with enough sun exposure for turtle eggs to properly develop is shrinking. Based on historical aerial photographs, the habitat has shrunk by about 70% in the past 15 years and is on track to be gone within the next 10 as trees and shrubs make their way back in and cast shadows over the ground. Because extensive survey efforts have not found any similar habitat nearby, the loss of that site to the turtles may result in females traveling even farther from the river to lay their eggs, possibly in lawns or along the edge of a road where the females are at great risk and hatchlings will face greater challenges as they attempt to find the stream in the fall. As such, we are now working with the landowner to develop a habitat management plan that will maintain or even improve this critical feature for the Wood Turtles, despite the fact that the successional process causing it to shrink is a very natural one.
As we expand our monitoring efforts over the next few years, we fully expect to identify sites where protecting Wood Turtle nests from predators is an almost mandatory move, but for now we are thankful that the most imminent threat to nesting Wood Turtles at the most critical site we are monitoring is an easy problem to deal with. Having a willing and enthusiastic landowner on board with Wood Turtle habitat management is also a huge plus and we are very excited to see the site managed for turtles in the very near future. Efforts such as this, in conjunction with a comprehensive conservation strategy for the rest of the watershed, will hopefully result in this population of Wood Turtles being protected from the threats that are ever increasing throughout the landscape that surrounds it.
