I try to protect the turtles... the raccoons and skunks like a feed of turtle eggs. The predators need to eat too. Perhaps I am interfering by protecting a few turtle nests.
I have built a dozen of these turtle nest protectors. They seem to work very well. The difficulty is in locating the nest. Turtles may have a reputation for being slow but they disappear like NinJa Turtles the minute I turn my back. They use their "slowness" as a guise and give you the illusion that you don't have to watch them like a hawk to keep track of their movements. The undiscovered nest beside the one that was protected (lower right) was predated by a raccoon.
Any turtle that hatches out when I am around gets a free ride to the lake... In 2012, 29 baby snappers enjoyed the free ride out of one nesting cavity - like the baby northern map turtle above.
The following is from Wikipedia:
Northern map turtles breed in the spring and fall. Most mating takes place in deep waters. The nesting period lasts from May to July. Unshaded sites with sandy soil is highly preferred. The female usually chooses well-drained areas for depositing the eggs. The nest cavity is dug with the hind feet. The size of the clutch is between 6 to 20. The eggs are oval, about 3.2 cm (1.3 in) long, and have a flexible shell. After the eggs are laid, the cavity is filled. They hatch after 50 to 70 days of incubation, and most hatchlings emerge in August to September. When a nest hatches late, the northern map turtle hatchlings have been known to overwinter in the nest. The female usually lays two or more clutches in one breeding season. The sexes of the young are determined by the temperature. At 25 degrees Celsius incubation produces a majority of males whereas 30–35 °C (86–95 °F) yields more females.