Timing the Mule Deer Rut

Although it was January, the rising sun was warming the desert air to a discomforting temperature. I set myself in the shadow of a gnarled palo verde as comfortably as possible to overlook the Sonoran desert canyon below. The terrain was steep, sharp, and dangerous. Saguaro, cholla, and ragged boulders frequented the desert landscape below. This was to be my first experience hunting the Sonoran desert for rutting mule deer. Earlier that morning I painfully discovered that everything I rubbed against would poke, prick, bite, scratch, or sting me. For an instant, my thoughts drifted back to the coolness of the high attitude hunting that I grew up with in the central Rockies where I would likely be wrapped in a down parka at this time of the morning.

A distinctive grunt from below brought me back to the reality of my first desert mule deer archery hunt. In no time my eyes were glued to my binoculars searching the landscape for whatever it was that could possibly make such a groan. A large heavy-antlered muley with up-turned Roman nose and swollen neck filled my glasses. Suddenly, the cactus spines in my pants and the soaring temperature didn’t matter as I gripped my bow and felt the symptoms of big-buck fever coming on.

At only 150 yards away, the big desert buck swaggered in my direction. I struggled to blend my silhouette into the palo verde trunk as my heartbeat pounded through my eardrums. I instinctively opened my mouth to breathe more quietly as I realized the glassy-eyed monarch was pacing straight for me and had closed the distance between us to 60 yards…

Today, mule deer subspecies are found all the way south to central Mexico and northward almost to the Arctic Circle. They range from the coastal ranges of the West Coast to the mid-western prairies in the East. Mule deer breeding time periods vary significantly depending upon latitude, and to an extent upon weather and hunting pressure. In the far north reaches of the mule deer’s range the rut can start as early as mid-October and run all the way into December. In the lower Rocky Mountains where mule deer are most plentiful the breeding season will start the beginning of November. I have, however, observed bucks in Utah and Wyoming breeding does well into January. In the Southwestern deserts and old Mexico the bucks will begin to breed in the latter part of December and peak in the beginning of January. However, last winter I saw a large desert buck chasing a small herd of does in February while quail hunting.

It is interesting to know how a mechanism such as breeding season synchronization and latitude can benefit deer from an evolutionary standpoint. There is a recognizable body size distinction in most animal species as you go north or south. Generally, the average body size increases as you move northward. I am always astounded with the pictures of the large barrel-chested mule deer I get from my college hunting buddy from central British Columbia. This principle of a north-south gradient is known as “Bergmann’s rule” among wildlife biologists. Trust me. The next time you’re with some huntin’ buddies, refer to this rule and they’ll all be inspired with your intelligence.

In the North, their large bodies enable them to survive more extreme cold due to the larger volume per surface ratio. Their early breeding period is synchronized because of the need for fawns to be born in early spring so they are large enough to weather their first winter on the northern range. In the southern reaches of mule deer country the late breeding period is in direct correlation with the summer’s monsoon season. These monsoon rains are very important to the deer population in the arid Southwest. Generally, the fawns are born in the beginning of monsoon season assuring the newborns additional browse and a sufficient amount of water.

Some studies show that the first heavy winter storms assist in triggering breeding. Many hunters believe the moon phase can trigger rutting behavior although there is little evidence of its validity. Heavy hunting pressure during breeding season can affect rutting behavior and ultimately have devastating effects on an entire deer population. Notice I emphasize the words “heavy hunting”.

Imagine it is breeding season and the bucks are compelled to the not-so-suitable habitat on a unit because of heavy hunting pressure. The does are more docile and feed heavily in the more suitable habitat away from the bucks when they come into estrus for the short duration of 24 to 30 hours every 28 days. During the estrus period, does that are ready to be bred have been observed traveling great distances in search of a buck only to tease the fatigued male into breeding. Most adult does will eventually be bred every year but it could be perilous in that the does may be bred later than their first estrus disrupting the breeding synchronization.

Severe winter storms and belated birthing could create risky situations for the fawns. Predation on fawns can be a significant problem when the breeding period is disrupted. In a properly managed deer herd most of the does will be bred in their first estrus. This creates a saturation of fawns on the ground during a relatively small time period. Mule deer predators know this time period all too well and feed heavily on the newborn fawns but can only consume so much. When does drop fawns during a larger time period caused by poor management there is a larger time frame when predators are primarily hunting fawns, and the number of fawns predated increases significantly.Fortunately, state wildlife departments understand how critical breeding season is and manage so there is minimal hunting activity during these periods.

Almost every state in the West allows mule deer rut-hunting opportunities either through landowner tags, lottery tags, or over-the-counter tags. These hunts give the hunter the chance to observe and stalk mature bucks that wouldn’t habitually expose themselves to the hunter. Arizona and New Mexico have great long-season over-the-counter archery hunts during breeding season for a general season price. Other states such as Idaho and Nevada have rut hunts in some highly coveted units although the drawing odds aren’t favorable. Montana is a great choice for a rifleman’s rut. The secret for success is to research different units for deer population estimates, percent of harvest, and lottery tag draw odds by using the state game department’s previous year’s big game report. By examining this information you can find the hunt that fits your specifications and your budget. By doing my own research and a little luck I ended up in the Arizona desert hunting rutting muleys last year.

However, my luck ran out when my arrow disappeared into a cluster of cholla barely missing the big buck’s chest as it trotted away down the dusty draw. All was not lost however, as my muley hunting is just another good excuse to get out and enjoy the great outdoors whether I am in the Sonoran deserts or the Yukon forests.