Rainfall and depredation of nests of the Painted Turtle, Chrysemys picta

It is commonly thought that predators use olfactory cues to find turtle nests and that these cues are diminished by rainfall. We studied the relationship between rainfall on the date of oviposition and depredation of nests of the Painted Turtle, Chrysemys picta, on a major nesting beach between 1996 and 2003. We analyzed two scenarios: rainfall versus no rainfall on the date of oviposition; and no rainfall versus intense or weak rainfall on the date of oviposition. For the first scenario, we found no consistent association between rainfall and nest depredation before hatching. In 1996, rainfall on the date of oviposition appeared to increase the chance of nest depredation; in 2000, it appeared to decrease the chance of nest depredation; and there was no statistically significant relationship in the remaining years or overall. In the second analysis, the relative amount of rain was associated with nest depredation before hatching. Nests constructed on days with a larger amount of rain were less likely to be depreciated than nests constructed on days with no rain or smaller amounts of rain. Nests constructed on days with smaller amounts of rain were more likely to be depredated than nests constructed on days with no rain.