After looking at some of the information, the final answer is, "it depends". If it was moon phase or length of light in the day then the breeding periods would be roughly the same in a region of the country, and it isn't. I know about 25 years ago I hunted about 30 miles east of where I do now and the rut was a month and a half earlier than it is now. They are still scraping the middle of April where I hunt.