Limiting tick populations by preserving habitat for predators
Lyme disease, carried by deer ticks, is spreading at an alarming rate across Michigan. What was once a “New England problem” is now a widespread Midwestern problem. Changes in climate, deer management, the transportation of ticks by humans over large distances, and tick predator habitat loss are the causes. Unfortunately, these contributing factors are expected to worsen and Lyme disease will become a common health risk in the Huron River watershed. For some, it is already.
Fortunately, there are lots of things we can do to protect ourselves from ticks. Experts recommend tucking long pants into boots or high socks, spraying pants and shoes with DEET or permethrin, and thoroughly checking ourselves and our pets for ticks daily.
Protecting our “tick destroyer” animal allies and their habitats can also reduce the risks of infection. Understanding why requires understanding the tick life cycle. Larval ticks are born uninfected. They typically attach to small rodents like mice for their first meal. They engorge themselves, fall off and mature. Now possibly infected with Lyme acquired from this first host, they can bite a human and spread the disease. Ticks need three meals to reproduce, and humans are only at risk of catching Lyme from a tick that has already bitten an infected host.
The good news is ticks and tick hosts have many natural predators. These species either eat ticks themselves or affect the ecosystem in ways that indirectly limit tick populations. Here are a few of our allies in the watershed.
Opossums
In southeastern Michigan, perhaps our greatest friend in the fight against ticks is the opossum. Often maligned for their appearance, many people mistakenly consider them a nuisance rodent. Opossums rarely cause problems for homeowners, but they are savvy and opportunistic eaters.
Opossums are amazing marsupials, diligent self-groomers that excel at removing ticks from themselves. One opossum will kill around 90 percent of the ticks that attempt to attach to their body, which amounts to a whopping average of 5,000 ticks in a typical season. Particularly in suburban and exurban environments—where Lyme disease is spreading rapidly—opossums serve as a front line against rampant tick populations.
While opossums are opportunistic foragers, they are known to feast on small rodents. If the host animal is covered in ticks, for the opossum it’s a bonus treat—like sprinkles on ice cream.
Foxes, coyotes, snakes, and raptors
Wild mice are top hosts for ticks, and research suggests that a major factor in the spread of tick-borne diseases is the loss of natural mouse predators. If mice populations were kept in check, uninfected larval ticks would either find other uninfected hosts or die without finding their first meal. Larger snakes, foxes, coyotes, and raptors eat mice, thus breaking the cycle of infection. In natural areas where these predators are protected, the number of infected ticks can be reduced by around 80%.
Frogs, Toads, and Fowl
Ticks thrive in moist, grassy wetland areas. Frogs and toads are bug eating experts, with a penchant for devouring any insect they encounter—including ticks.
Fowl make excellent neighborhood “tick defense” systems. Ducks and chickens constantly peck away at insects, eating whatever they find. For people living in places that raise chickens or ducks, these birds can significantly reduce the risk of picking up a tick in the backyard or garden. Wild turkeys also reduce tick populations substantially, and turkey populations are thriving thanks to decades of dedication from conservation and game organizations.
Protect habitat, wildlife allies, and people
We clearly have a lot of animal friends in the fight against ticks and Lyme disease. In the Huron River watershed, one of the most important things we can do is protect the habitat of these vital predators in our ecosystem. Protecting large tracts of natural land for predators is especially important. Conserving or restoring wetlands provides more room for frogs and toads. Healthy grasslands are excellent hunting grounds for hawks and snakes. Allowing mature forests to grow will encourage owls to stay close by. Opossums are very adaptable, but they still need wetlands, woods, or natural spaces to get away from people and stay safe from their own predators. In urban and suburban areas, large brush piles can provide daytime resting areas for these nocturnal friends.
Habitat restoration is important, too. Invasive barberry plants provide great nesting areas for mice, who are able to tuck safely within the thorny branches—protected from predators. Removing these plants has been shown to decrease mouse populations, thus slowing the spread of ticks.
While you take the necessary steps to keep ticks off yourself, kids, and pets, also consider supporting local conservation efforts and land conservancies that protect vital, disappearing habitat for wildlife. Please let others know about the benefits of our allies, especially opossums, who could use a public relations boost.
This blog post was originally published March 1st in the Huron River Report, Spring 2021.