Promising Solutions For Humane Population Management
Not all wild animals receive the same level of protection or concern for their welfare. While endangered species and charismatic megafauna are defended and supported by many conservation groups and animal advocates, other animals are widely classified as pests. At best, these species are ignored, but at worst, they are exterminated in ways that cause great suffering to the individual animals belonging to those species.
By controlling the population of a pest species, the intention is usually to manage an ecosystem or help another species (human or otherwise), but these methods often come with the cost of many painful deaths.
Wild Animal Initiative, an organization dedicated to scientific research with the goal of improving wild animal welfare, has reviewed several humane alternatives to traditional population control methods. Though there is still a need for more research and willingness to adopt these humane methods, they show great potential. These interventions may facilitate ecosystem management while also increasing wild animal welfare at the individual level by decreasing the negative effects of overpopulation, such as starvation, disease, and stress.
Gray squirrels were introduced to the U.K. from the U.S. in the late 19th century. Studies have shown that gray squirrels are better adapted for urban foraging than red squirrels, so it’s easier for them to thrive in places with more dense human populations. Also, gray squirrels are resistant to squirrelpox but can transmit the disease to red squirrels. Gray squirrel populations in the U.K. have increased dramatically since their introduction while numbers of the red squirrel have declined, and though the exact cause-and-effect relationship is not yet clearly measurable, there is an apparent conflict of interest between the squirrels of both species.
Until recently, red squirrel conservationists in the U.K. recommended killing gray squirrels with poison or guns. These methods caused suffering for other non-target species in addition to the gray squirrel, and did not even achieve their goal of decreasing the number of gray squirrels.
Earlier this year, the U.K. government began distributing an edible contraceptive to gray squirrels, delivered in a bit of tasty hazelnut paste. This contraceptive, known as GonaCon, had previously been tested and proven to reduce birth rates for certain other species, such as prairie dogs. The approved method for delivering GonaCon to gray squirrels in the UK prevents fertility in both males and females, and the device that holds the contraceptive is not accessible to red squirrels.
Pigeons are common in urban environments all over the world, and they are often viewed as a nuisance. In the United States, a pesticide called Avitrol is used to induce seizures in some pigeons, which is intended to scare the other members of the flock so they’ll flee the area. The seizures can last hours, and the birds might experience pain during that time — the precise experience of the bird during the episode is unclear. Birds who survive poisoning by Avitrol might also suffer injuries that debilitate them beyond the episode.
As an alternative to Avitrol and even more lethal products, Wild Animal Initiative’s research team has designed a field experiment with the goal of decreasing pigeon populations with a humane contraceptive. The focal contraceptive, known as OvoControl-P, is distributed via bait and has been used since 2007 as a non-lethal method to shrink rock pigeon populations in the U.S. There are numerous uncertainties about the immediate and indirect welfare effects of this intervention on pigeons, which Wild Animal Initiative has considered in its proposed plan and hopes to work toward answering. This project is currently in development.
Scientists have not yet confirmed that insects can feel pain, but it’s possible. Because so many insects are killed by humans each year (an estimated 3.5 quadrillion in the U.S. alone), and because those deaths are potentially excruciating, there is a good chance that making pesticides more humane would prevent a significant amount of wild animal suffering.
At this point, there are too many unknowns that prevent researchers from recommending a particular pest control method as more humane than standard pesticides. But certain non-lethal methods might be the best bet to avoid insect suffering. Through the sterile insect release method, for example, sterilized insects are rereleased and then compete with fertile individuals for mating opportunities. Over time, this competition leads to an overall population decline with each subsequent generation. This 2019 report produced by Wild Animal Initiative contains much more information about the Sterile Insect Release Method and other interventions for insects.