Turtles in south-central Ontario are in peak nesting season in the first two weeks of June. This is when female turtles will be crossing roads, and often nesting on road shoulders. Turtles take years to mature, and it takes many more years (up to 60 years for snapping turtles) to have one successful hatchling reach adulthood to replace itself in the population. This is because of very high nest predation rates, especially in exurban areas that have attracted more raccoons and predators than would be found in the wild, and also because of the sensitivity of eggs to temperatures. Climate Change may be making it harder too for nests to hatch successfully.
Upload: Nesting chart
If you live in an exurban area/rural area but near towns and settlements, and a turtle as laid eggs on your property, you can build a nest cage protector and save the nest from predators. Upload this Nest Cage Protector Design... 
Or build your own! - just make sure that the young hatchlings can escape (usually needing 2 inch by 2 inch exits) and that the cage is not highly visible to hungry birds that like to eat the young hatchlings.