April Deer Management by TR Michels
The deer should be on their spring home ranges, looking for new green growth to gain back the fat they lost during the winter. This is when bucks begin growing their antlers, so if there is not enough forage for the deer to eat, you may want to provide supplemental feed and minerals to help the bucks grow larger racks. If you can, now is a good time to do a soil test and enrich and fertilize the soil. It’s a good thing there is not too much for the deer manager to do this month, because it’s time to scout and hunt turkeys. You can do some spring deer scouting while your are at it; whitetail trails, tracks rubs, scrapes and shed antlers are very evident in early spring. The information you gain now may tell you where to find the deer this fall and winter.
Seasonal Home Ranges
In many areas even non-migratory whitetails use four different home ranges; one each for winter, spring, summer and fall. In general, one end of the seasonal home range consists of the “core area” and daytime bedding sites, often in a wooded area, where the deer spend most of the day. Again, in general, the other end of the seasonal home range consists of an open feeding area, where the deer spend most of the night, and where they have night bedding sites. Buck home ranges may be from two to five times the size of doe ranges during the rut, but they often restrict their movements to a small core area during the winter, spring and summer.
These seasonal home ranges may be several miles apart, or they may overlap each other. In some cases the core area of the individual deer may be the same, but the area and size of the habitat may vary. The deer may use the northern area of its habitat in the summer and the southern area in the winter. It may use wooded areas in the winter to stay warm and open areas in the summer to stay cool.
In some areas whitetails may move several miles in the spring and fall as a result of snow depths, flooding or lack of food. The availability of food and the type of cover needed by the deer during each season determine which part of the annual home range the deer will use. Deer using a soybean field in August may move several miles away during the rut or the hunting season. What this means is that the deer you see and hunt in the fall may not be there for you to feed in the winter, they may be miles away. If they aren’t, and there are no other deer in the area, there is no reason to feed in that area. Before you begin a feeding program, determine how many deer there are in the area; and when and where the deer use the area during the year.
How Nutrition and Health Affect Breeding Activity and Fawning Rates
It’s not often talked about, but researchers have discovered that poor nutrition can affect not only the timing of the rut, but also the activities of the rut. During one of Dr. Karl Miller and Dr. Larry Marchinton’s studies in Georgia it was found that the numbers of rubs in an area were related to the mast (acorn) abundance, and that during years of little mast production, rub densities were reduced by thirty to sixty percent. It was also found that rubs were less common in pine and mixed pine-oak stands than in oak or primarily oak and pine stands. The researchers thought that the presence of rubs in mast producing areas was because of the type of food in the area, not necessarily because of the type of trees in the area. Regeneration areas and thick hardwood types were avoided as rub sites on all the Georgia study areas; and old fields were highly favored as rub sites.
I find this to be true in the upper Midwest too; bucks rub more near oaks when they are dropping acorns, and near agricultural and old field edges, than they do in dense hardwood forests. But, I have seen numerous rubs near old clear cuts and old fields that have begun to regenerate with saplings. I suspect that rubbing in agricultural areas may be dependent not only on the amount of acorns available, but also on the type and amount of other preferred food sources in the fall, such as alfalfa, soybeans and corn. Because the condition of the deer in the Georgia study was highly dependent on acorns, and their physical condition was poor because of low acorn production, it resulted in a less intense rut. The deer were simply not healthy enough to be as active as they would normally be. If the deer in your area suffer from poor nutrition, because acorn or other mast production is down, or because agricultural crop production is low, you may see less rubbing (and possibly scraping) than normal. Poor nutrition may also result in less daytime trolling, chasing and breeding activity, resulting in a longer than normal breeding phase.
There is also evidence that poor nutrition and health may cause does to come into a later than normal first estrus, or not come into estrous at all. Poor nutrition can affect late born doe fawns (which might breed during their first year if they are healthy), older does, and does that bred late the year before. Does that were switched from low to high nutrition in autumn almost tripled their fawning rates. Does that breed late, give birth late and wean their fawns late, are often nutritionally stressed during the fall. Any doe that nurses is stressed, and the more fawns the doe has the more stressed it is. Poor nutrition may also affect male/female fawning rations. Does on poor nutrition often produce more males, while does on good nutrition often produce more females. This may explain why does in over populated areas often produce more buck fawns. Studies of over 1,600 does in Minnesota show that 15-20 percent of the adult and yearling does may be bred after the third week of November, and that up to 50 percent of the yearling does may breed after December first.
Poor doe nutrition can also result in later development of the does fawns, and of her fawn’s eventual offspring. What this means is that the timing of the rut, the health of the deer in the winter, the reproduction rates of the does, and fawn survival are dependent on good herd nutrition and health. If the deer are nutritionally stressed during any one year, it may affect breeding activity and survival rates for the next few years, and for the next few generations of deer.