New research reveals that efforts to control coyote populations through culling are not only largely ineffective but often have the opposite effect, causing their numbers to rebound rapidly and sometimes exceed previous levels. A comprehensive study combining decades of field data with advanced population modeling demonstrates that these resilient canids possess a remarkable suite of biological and social mechanisms that allow them to compensate for population losses. The findings challenge long-held wildlife management practices and suggest that lethal control methods can inadvertently create more of the human-wildlife conflicts they are meant to prevent.
The study highlights a phenomenon known as compensatory reproduction, where the intense pressure of culling triggers a surge in coyote birth rates and survival. When stable family groups are disrupted by the removal of dominant animals, the pack’s rigid social structure breaks down, enabling younger, subordinate members to breed. This shift, combined with an influx of new coyotes into the vacated territory, results in a population that quickly recovers and can even become denser than before. These insights are prompting a critical reevaluation of coyote management, steering the focus away from population reduction and toward strategies that promote coexistence.
The Biology of a Rebound
At the heart of the coyote’s resilience is its flexible social system and reproductive biology. In a stable, unexploited coyote population, a pack typically consists of a dominant alpha pair and their offspring from previous years. This social hierarchy acts as a form of natural population control, as the alpha pair actively suppresses the breeding activity of subordinate females within the group. In most cases, only the alpha female will produce a litter each year.
Lethal control methods shatter this delicate social balance. The removal of one or both members of the alpha pair dissolves the pack’s hierarchy. Without the dominant pair to enforce suppression, multiple females in the group may become reproductively active. This can lead to a single territory producing several litters in a season instead of just one, dramatically accelerating population growth. The study found that in heavily culled areas, the proportion of breeding females can jump from less than 50% to over 90%.
Furthermore, the research confirms that surviving coyotes respond to decreased population density with larger litters. With fewer coyotes competing for resources like rodents, rabbits, and fruit, females are healthier and can support more pups. Average litter sizes can increase by 30–40% in these conditions. Combined with a higher survival rate for pups due to abundant food, these biological responses create a powerful engine for a rapid population comeback.
Modeling Population Dynamics
To understand these complex interactions, the research team developed sophisticated computer models that simulated coyote population dynamics over long periods under various management scenarios. These models were not based on theory alone; they were informed by over two decades of empirical data collected from coyote populations across different environments, from rural ranchlands to dense urban centers.
Field Data Integration
The foundation of the model was long-term field data from studies involving GPS-collared coyotes. This tracking information provided precise details on territory size, social interactions, dispersal patterns, and survival rates. Researchers were able to document exactly how coyotes responded to the loss of pack members. A key observation was the “vacuum effect,” where a territory cleared of its resident pack was almost immediately re-colonized by transient coyotes from surrounding areas. These newcomers, often young and seeking to establish their own territory, contribute further to the population surge.
Simulation of Culling Effects
The computer simulations allowed the scientists to test the effectiveness of different removal rates. The models consistently showed that even intensive and sustained culling—removing up to 70% of the population annually—failed to produce a long-term reduction in coyote numbers. Following an initial dip, the simulated populations invariably bounced back to, and often surpassed, their original density within one to three years. The simulations demonstrated that to achieve a lasting population decrease, control efforts would have to be implemented at an unsustainable intensity over a vast geographical area, a practical and financial impossibility for most agencies.
The Paradox of Lethal Control
The study’s findings present a stark paradox for wildlife managers: the very tool used to reduce coyote numbers often makes the population younger, more reproductive, and potentially more prone to conflict with humans. When established packs are dismantled, the deep-rooted territorial knowledge is lost. Older, experienced coyotes are generally more adept at hunting their natural prey and avoiding humans.
In contrast, a population dominated by inexperienced juveniles is less efficient at hunting traditional prey. These younger animals are more likely to turn to easy, high-reward food sources found in human-dominated landscapes, such as unsecured garbage, pet food, and sometimes, small pets. By removing the established, wary adults, culling can inadvertently select for a population of bolder, less predictable animals, potentially increasing the frequency of negative encounters with people and livestock.
This creates a frustrating cycle for ranchers and communities. They invest significant resources in lethal control, see a temporary reduction in coyote sightings, but soon face a new, larger, and potentially more troublesome population of coyotes. The study emphasizes that this outcome is not a failure of effort but a predictable ecological response to a flawed strategy.
A Shift Toward Coexistence
In light of this overwhelming evidence, many wildlife biologists and managers are advocating for a fundamental shift away from population control and toward conflict mitigation. The research underscores that since coyote populations cannot be effectively eliminated, the focus must be on changing human behavior and managing landscapes to minimize opportunities for conflict.
The most effective strategies are non-lethal and proactive. These include community-wide education on securing attractants like trash and compost, feeding pets indoors, and using fencing to protect livestock and poultry. Another key tool is “hazing,” which involves using loud noises, bright lights, and assertive actions to re-instill a coyote’s natural fear of humans. Consistent hazing by community members can teach coyotes to keep their distance from yards and neighborhoods, effectively creating a “landscape of fear” that encourages them to stick to natural spaces and prey.
For agricultural producers, a growing body of research supports the use of non-lethal deterrents such as livestock guardian animals (like dogs, llamas, and donkeys), fladry (flags on fences), and sophisticated light-and-sound devices that scare predators away. These methods are often more cost-effective and have a higher long-term success rate than lethal control, as they address the root cause of the conflict—unprotected livestock—rather than an endlessly regenerating predator population.