Another factor is nutrition, this is why in the south we typically associate the rut with the first good freeze. It is usually when the nutritional value of the plants drops to the lowest and it triggers the deer to reproduce before their bodies start depleting due to lack of nutrition throughout the winter. this is all very interesting that the harvest moon, hunters moon, and first hard freeze (in the south), all happen around the same time as the plants lose their nutritional values for us in texas. then due to some younger does (late born fawns) there will be a second rut usually about 2-3 weeks after the first lasting about a week, these does probably had not fully reached reproductive maturity for the first rut. This is just what ive learned over the years. happy hunting.