Turtle researchers often use depredated nest surveys as an index of the total number of turtle nests laid. However, it can be difficult to determine whether an empty nest hole indicates a depredated nest or not. In such cases the presence of depredated egg shells clearly indicates that a nest was present; similarly, absence of eggshells may be interpreted to mean that no nest was present. We measured the amount of calcium in raccoon (Procyon lotor) scats at depredated nests of diamondback terrapins (Malaclemys terrapin) at Jamaica Bay Wildlife Refuge, New York, and found that during the first half of the nesting season, raccoons ingested egg contents without their shells, but during the second half of the season they ate whole eggs with shells. Researchers who use the presence of egg shells during depredated nest surveys should be aware that their counts may be affected by this change in predation behavior by raccoons.

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