The whitetail deer breeding season in Iowa extends from October through January. Breeding by adult does starts in October and continues through December with 70 percent of the breeding occurring from November 2-23. Breeding activity by fawn does which are six to eight months old extends from November through January with 75 percent of the breeding occurring between November 17 and December 22. Fawn whitetail does reach a peak in breeding activity about three weeks later than adult does.
Whitetail fawns are born from early May through August after a six-and one-half month gestation period. The peak fawning period is from the last week of May through the first two weeks of June. Fawns are typically weaned at three to four months of age but stay with the doe until they are about one year old.
Adult does normally produce two fawns, but three or even four are possible. About 70 percent of the whitetail fawn does breed during their first fall and usually produce only one young. Iowa deer have an extremely high reproductive rate compared to other states because of the nutritious food, relatively mild winters and lack of parasites and diseases.
Bucks are capable of breeding at one and one-half years of age but the majority of the breeding is performed by the older, more dominant bucks. Does are receptive to bucks for about 24 to 48 hours and are vigorously pursued during this period. If for some reason, does are not bred, they will again come into heat about 28 to 29 days later. This cycle may be repeated two to three times if the doe is not bred. A whitetail doe bred late in the fall will have her fawn late in the summer, which accounts for occasional reports of small deer seen during the hunting season.
Wishes For Wildlife Foundation members identify the late hatch and pay close attention to sustaining them through the winter months. How is this achieved? Members provide the small deer an additional feeding after the large deer are full. This is done several times a day.