The Shepaug River has a robust population of snapping turtles, evident by the abundance of females observed nesting in May and June. Many find the preserve’s low-lying, sandy fields and trails as adequate sites to excavate a shallow bowl and lay about 30 white eggs. Once covering them up with soil, the female returns to the river. One spring afternoon, an anxious individual had me reeling in line and wondering if I could outrun a bear while wearing waders. After noisily plowing into a fallen log on the far bank three times, moving it substantially, she finally barreled over the top and tumbled into the water.
Up to 90% of nests may be destroyed during the 80-day incubation period by predators like mink, raccoon, skunk, crows, and snakes. An interesting study conducted last year in Ontario examined cues used by predators to detect and depredate snapping turtle nests. They found that out of three cue types (visual, tactile, and chemosensory), nests with a tactile (touch) cue were significantly more likely to be depredated than nests with a visual or chemosensory (smell) cue. Furthermore, combining a tactile and chemosensory cue had an additive effect, increasing the probability of nest predation.
Oddie, M.A.Y., S.M. Coombes, and C.M. Davy. 2015. Investigation of cues used by predators to detect Snapping Turtle (Chelydra serpentine) nests. Canadian Journal of Zoology 93: 299-305.
