Breeding frenzy: If you love wildlife, let large animals be during their annual fall mating season

What is the rut and how are humans impacting the rut?

The rut is probably the most vital event in a species’ yearly life cycle. The rut is the mating season, usually fall, for many large mammals. It generally involves migration through wildlife corridors to a specific rutting site.

The most well-known rut in our area involves elk. The bugling and rutting activity is something that thousands enjoy each year. The choices humans make that disrupt the migration corridors or the sites where the rut occurs may cause a reduction in population or even the elimination of that herd entirely.

Many animals have a mating season. The animals that are obvious, to those that watch wildlife, are the large ruminates in the state. That includes mule deer, white-tailed deer, bighorn sheep, moose, rocky mountain goats, pronghorns, and bison. The only one of those animals that do not live in a wild situation in Eagle County is the bison.

Why is there a specific time to begin the rut for these animals? The gestation period (pregnancy) needs to match up with seasonal conditions. When females are impregnated in the fall, they give birth in the spring when it is warmer, there is less severe weather, and plants are greening up. All are factors needed to help vulnerable newborns survive.

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The goal of animals in the rut is to produce future generations. The rutting season varies by species in terms of length and time. The timing is based on the photoperiod (amount of daylight each day). As darkness increases a hormone called melatonin, which is produced by the pineal gland in the brain, begins to increase and that is what triggers females to come into estrus. In males, melatonin increases the levels of testosterone. The behavioral and physiological shifts observed during the rut are triggered by these hormones and that leads to the behavior we observe during the breeding season.

For males, melatonin causes an increase in testosterone and that causes a major change in aggression, interest in females, and significant physiological changes. The aggressive nature of the males can be dangerous for hikers and bikers.

Moose can be extremely dangerous. A hiker with a dog is in even more jeopardy. Moose see all canines as predators and will attack aggressively. Moose react to all dogs in the same way they would to a wolf, a major predator in the wild. They attempt to crush the canine with their hooves.
 
CPW recommends that people follow these tips to stay safe around moose:

• Maintain a safe distance between you and the animal. 
• Move slowly and not directly at them. Back off if they exhibit signs of aggression, such as the hair on their neck standing up, licking their snout, cocking their head, and rolling their eyes and ears back.
• Keep pets away and dogs on leash.
• If a moose displays aggressive behavior or begins to charge, run as fast as you can and try to put a large object between you, such as a boulder, car, or tree, and the animal

Closing trails may seem like a good option to avert problems with moose. That would be impossible because of the extensive range of moose in Colorado.

During the rut, deer, elk, and moose have developed antlers and behavior to make themselves more visually appealing to the females. Secretions from glands, soaking in their own urine, attacking bushes and trees also make them stand out for the female. Battles using their antlers are also common. Bull elk also bugle (a sound like a whistle) during these displays.

Bighorn sheep rams will often snort loudly. When they challenge other males, they walk up beside them head to tail and kick the other animal. They then back up, face each other at 10 feet or more and charge hitting head-to-head at a speed of up to 35 miles per hour. Bighorn sheep may do this hundreds of times in an afternoon.

Rocky mountain goats have threat displays but rarely fight. Puncture wounds are sometimes seen in males.

Pronghorn males will often grunt and will protect their harems and territories with pushing and head-to-head fighting matches.

What is often interesting is to watch younger males of any of those species. They will roam the edges of another male’s territory waiting for their chance to mate with a female. While the bigger males are busy showing their dominance, the younger males often get a chance to mate.

All these species communicate in three ways during the rut. They make all kinds of displays visually. They express themselves vocally and have scent-based communications. They produce secretions that contain pheromones and other compounds. These secretions are often rubbed on trees, twigs, and grass to communicate with other animals. Ungulates have as many as seven external scent glands. One of those glands is the preorbital gland in front of the eye, which expands dramatically during the rut.

The rut requires a huge amount of energy on the part of the males. A lot of energy went into building the antlers ungulates have. Because this is in the fall, males may have used a lot of energy and body resources. They enter the winter and have a difficult time surviving.

One of the difficulties for many species is that these animals have a summer range, and in the fall, they migrate to their winter range which is important for breeding and nutrition. In Eagle County, several of the corridors these animals use and the winter range itself is being blocked by fencing. Fencing along the interstate may have made a huge difference in reducing car-animal collisions, but the fencing may have created a population decline because the animals are unable to utilize all their historic range. People who have lived in the county for an extended time often comment on the fact that animals that were in an area are no longer seen.

In several places in the county, large areas of summer and winter range may be totally removed from access by animals due to residential and commercial development. Because of that, these animals may suffer a decline in breeding success during the rut. Some people say wildlife will find other areas. Research has found that that is often not the case. Those animals die.

Another problem during the rut is the impact of recreation. Hiking, biking, ATVing, snowmobiling, and a simple desire to view this display in nature bring people into areas that could impact the rut. Noise, dogs, and close encounters will be distractions during the rut and will reduce breeding success. If the area, trail, or road is marked as a closure, do not enter.

Rocky Mountain National Park now closes several areas to all use during the elk rut. In the 50s and 60s, a trip to the east side of Rocky Mountain National Park to view the rut was a quiet and exciting experience. Few people were there. It was like tailgating. Lawn chairs, Coleman stoves, and a lot of food, including S’mores, were consumed while waiting for the elk herds to appear.

You could easily stop almost anywhere along the roadway to view and hear hundreds of elk in the herds that form. As time went on the number of people increased, visitors were approaching elk and disturbing the rut and placing themselves in danger. From Sept. 1 to Oct. 31, park officials put closures in place and prohibit travel on foot or horse off established roadways or designated trails from 5 p.m. to 10 a.m. 

Another increasing problem is the use of drones in these areas. The unfamiliar noise may cause the animals to flee, using additional energy. In many places, the use of drones is prohibited so that they do not interfere with wildlife. Fines and loss of the drone may be the penalty for their illegal use.

Just like the issue with bears in trash cans, the behavior and choices people make are the problems. The bottom line is that, if we want to continue to enjoy wildlife, we must make choices that do not interfere with the natural cycles in this environment. As more people move to this area, building, zoning, and our choices for recreation must be done with consideration on what impact it will have on all wildlife. Wild animals are not able to vote or sign petitions. We can. Get involved!

Rick Spitzer is a renowned wildlife photographer and longtime local who lives in Wildridge. The Eagle County Community Wildlife Roundtable is a collaborative partnership with the White River National Forest, Colorado Parks and Wildlife, Bureau of Land Management, local government entities, community members and citizen scientists. The purpose of the Eagle County Community Wildlife Roundtable is to gather a group of diverse stakeholders in the valley to understand and address issues facing wildlife populations.