Written by: Adam Bocskei, Emma Ross, Jesse Beauchamp & Madison Penton
Historical Profile: The wide distribution of the Coyote, Canis latrans can be attributed to the influence of man on the landscape. The impacts of man have swept North America with deforestation, agriculture and the eradication of apex predators such as Grey Wolves and Cougars (Gompper, 2002). Coyotes have taken advantage of the newly opened space and freedom from predators to expand from Central America down to Mexico and up into the fringes of the boreal forest. Coyotes have been documented in Central America and south central Mexico previous to the colonization of Europeans (Hidalgo-Mihart, M. G., et al, 2004.). The influence of man on coyotes began when the European settlers arrived in the 1600’s to 1700’s and began to farm livestock and create crop lands. Upon the arrival of the Europeans, the close relative of the Coyote the Grey Wolf, Canis lupis , became a symbol of fear and was relentlessly hunted until extirpation occurred (Gompper, 2002). Due to the lack of competition from grey wolves the coyote was able to expand its populations and territories since it was quickly becoming the new apex predator. (Hidalgo-Mihart, et al, 2004.).
Figure 1: The comparison of a wolf and a coyote, distinguishing facial features. (Richard Badger, 2011; http://www.richardbadgerphoto.com)
Once the population began to increase and progress across the landscape it was not long until the Coyote was dispersed across the United States, into Canada and down through Mexico as far as Panama. In about 200 years the coyote had expanded its range from just the prairie lands in Central America to encompass the land from coast to coast across North America and Mexico (Gompper, 2002), for example the colonization rate in Maine between 1968 and 1974 was estimated at 1867 km2/year (Gompper, 2002). Since the population expanded so rapidly and into urban areas, people began to express concern about the safety of their livestock, effects on native animal populations and the safety of children and pets within urban environments. At this point citizens began to take matters into their own hands and started to hunt coyotes in the hopes that they would be able to keep the population at bay (Gompper, 2002). Since the expansion of agricultural practices and human modified lands Coyotes have taken advantage of the space and unlimited resources we provide for them in the form of livestock, rodents and domestic animals. In 16 western U.S. states, livestock deaths due to coyotes result in estimates of annual economic losses of between $4.4 and $27 million, and more than 97,000 coyotes per year are killed at an annual cost approaching $20 million (Gee, Magleby, Bailey, Gum, and Arthur 1977).
Ecological Connections: Difficulties in managing coyote populations can be attributed to ecological landscape changes that have favoured the innate traits of the species. Because of their opportunist behaviors, coyotes have grown to exploit a number of food sources made available by agriculture practices and human habitation. Coyotes’ opportunistic behavior is also what has influenced them to exploit livestock practices, such as preying on lambs and calves (Windberg & Mitchell, 1990). Coyotes would be considered a generalist, r-strategist species. This is because coyote age structure tends to be younger, adults have low survival rates and high reproductive rates, and younger animals are more likely to breed than older animals (Gese 2005). Coyotes may hunt in packs and pray on larger animals, such as ungulates, but are also able to feed themselves independently on other foods (Bekoff, Diamond, Mitton, 1981). The potential diversity of coyote diets and hunting strategies increases their survival and reproduction rates as they are not reliant on any particular food, and can adapt easily to changes in resource availability (Surjan et al. 2000, Lefcheck et al. 2013).
Figure 2: A coyote in a winter habitat, searching for prey. (Richard Badger, 2011; http://www.richardbadgerphoto.com)
Critical Assessment of Management Options: According to Bergman & Huot (2007), management attempts have been impeded by a growing public concern over the methods used. It is clear that an effective management strategy is needed and that the chosen strategy will have to “appeal to the public’s interest in the humane treatment of coyotes” (Bergman & Huot, 2007). Given that we know coyotes respond to a higher mortality rate with an increase in fecundity, and that the public is averse to lethal methods of controls, it follows that non-lethal methods of control should be the focus so that both of these considerations can be satisfied (Sacks, 2005; Bergman & Huot, 2007). While culling is now recognized as an efficient means of control, it will be included below to add context.
There is always the option of leaving everything the way it is, and doing nothing, but would not result in any positive impact on livestock loss. 116 ,700 head of livestock and approximately $48,185,000 are lost every year (NASS, 2011). By allowing coyotes to continue their assault on livestock, the cost of damages each year will continue to add the total . Unhindered access to livestock as a food source will also increase the coyote population, potentially leading them to colonize an even wider range (Andelt et al., 2008). This may also result in the coyotes predation on other wildlife and if the coyotes source of resources decreases to an amount that can’t sustain the population they could become more hostile when in search for food.
One of the means of coyote management is the use of electric fences. Nass & Theade (1988) compared sheep loss on farms before and after the installation of electric fences. They found that after an electric fence was implemented, the average percentage of sheep loss dropped from 3.9% to 0.3%. Although most farmers in this particular study indicated they were satisfied with the effectiveness of the fences, 95% of them also reported the need for frequent maintenance due to electrical shortages, fence damage from vegetation, and wash out. Some also indicated that coyote were able to exploit areas of wash out and get under the fence. Another limiting factor in this approach is cost. Based on the economy in 1988, it was estimated that this method of management must prevent the loss of 37 sheep per year to justify the building of an electrical fence around 640 acres (Nass & Theade, 1988). This would lead to the conclusion that this management strategy is most effective for farmers with a high volume of livestock as well as a high risk of predation.
Alberta Agriculture and Rural Development (1998) state that a viable alternative to guard dogs is a guard donkey. A donkey has an inherent dislike of canids and will bray, bare its teeth, chase and attempt to kick and bite dogs and coyotes. Similar to the guard dog method, the guard donkey method requires very specific considerations in order to train the donkey to effectively manage livestock loss. Some of these considerations include only using female or gelded male donkeys. These donkeys should also be introduced to livestock 4-6 weeks prior to the onset of predation. Additionally, only one donkey should be used per group of livestock so that a bond is formed with the livestock and not other donkeys. The main drawback of this management method is that a donkey is only effective when guarding smaller, open pastures. Because only one donkey can be used effectively per livestock group, it follows that a donkey’s effectiveness decreases as the number of livestock to be protected increases (Alberta Agriculture and Rural Development, 1998).
Introducing guardian dogs into the livestock pasture is another option that may be viable for the management of the coyote. Livestock protection dogs is something that has been used in Europe for many years to protect livestock from coyotes but only established in North America in the 1970’s (Gehring, VerCauteren, & Cellar, 2011). The protection dogs act as a pack to protect the herd, and work most effectively when they are introduced at a young age. Many studies have been done to confirm that introducing guardian dogs has significantly reduced the coyote predation, in some cases from 11%-100% (Gehring, VerCauteren, & Landry, 2010). Dogs that are beneficial for this option would be mastiff and great pyrenees, both breeds are great herding dogs and have been used historically as livestock protection dogs. This option is one that is non-lethal and can be very effective. The cost of this option is moderate, the cost is the initial price of the dogs and the time training the dogs to protect the livestock and stay within their territory. This option will be the least expensive option when comparing it to livestock losses.
Sterilizing alpha males is another effective option because it is non-lethal and it is ethically and environmentally sound. In a study conducted over a five year time span it was concluded that sterilization of the alpha male was the most effective method for management. They found from their study that since the mated pair didn’t have any new young pups to feed they reduced the amount of predation on lambs by the alpha male (Conner, et al. 2008). And they also found that sterilized alpha males still defended their territory therefore not allowing other alpha males into the territory excluding others from killing prey and it was suggested that this could have a multi-year effect (Conner, et al. 2008 ). Although this method is ethical and would be viewed positively by the general public, it is not economically feasible nor is it the best approach for management.
Table 1: Comparison of doing nothing, culling the coyotes, introducing livestock protection animals, sterilization and introducing electric fencing barriers. To do nothing will continue on a downward spiral, to cull will increase the wolves to a significant amount and introducing guardian animals may be the most viable, cost-effective option. Sterilization although a very effective method is extremely costly and the electric fence may also be a viable option (Gehring, VerCauteren, & Cellar, 2011).
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