I recently got an email from the Westchester/Putnam branch of the QDMA in regards to timing the rut in Westchester County. I found it very interesting and thought I would share:
Fact: Whitetail deer have a gestation period that is approximately 198 days
By observing when the majority of fawns are born and counting back 198 days we can estimate when the peak of the rut takes place. This also gives us a parameter to look at in terms of timing your particular deer herd with does that cycle into estrous. As hunters how do we interpret fawn birth dates?
Generally speaking here in New York, our peak breeding takes place between November 10th and November 24th. Following this, the majority of fawns will be born between May 27th and June 10th when summer foliage is at its peak. This is optimum for fawn survival because there is more food available in non-agriculture areas. The buck fawns born earlier in the spring become the bigger racked 1 1/2 year old bucks in the herd.
Does cycle every 28 days and does that are not bred during this time will cycle once again around December 5th through December 19th with births occurring between June 24th and July 10th. By this time, the deer have already been browsing on the foliage for two months and the foliage that is easiest for the fawns to reach is slowly disappearing. For new born fawns easy browse is becoming less available.
Populations with extremely skewed sex ratios and high deer densities, like Westchester County, breeding occurs again around January 5th (I witnessed a buck breed a doe from my office window on January 25th). These fawns will be born Late July and August and are at a big disadvantage to those born earlier. They will have lower weights and smaller antlers for the first few years of life unless adequate high quality food is available. Unfortunately, high quality food is not overly abundant for much of the lower Hudson Valley. The body and weight of these deer at age 1 1/2 will be smaller then those born two months earlier. These late born button bucks are usually the small spike bucks at age 1 1/2.