Purpose
We work to protect the Butler’s gartersnake from threat by supplementing wild populations and perfecting conservation techniques.
Butler’s gartersnake (Thamnophis butleri) is one of Ontario’s smallest snakes, typically reaching just 38 to 51 cm in length. They can be spotted in dense grasslands, wet meadows, and prairie edges where they spend most of their time hidden underground or beneath cover objects like boards, rocks, and logs. They are distinguished by its narrow head and neck, and three yellow longitudinal stripes running the length of their bodies. Their belly is pale green or yellowish with black spotting along the edges.
The male and female look almost identical, the main difference is that the males are smaller than females and possess slightly longer tails proportionally.
Butler’s gartersnake habitat in Canada includes tallgrass prairie, old fields, and grassy areas often close to wet or damp environments. Although Butler’s gartersnakes are typically only found in open grassy areas, they can still be found in both natural and human disturbed habitats. Historically, the Butler’s gartersnake’s diet consisted largely of leeches, but this species has since shifted its diet almost completely to non-native earthworms.
The Butler’s gartersnake has a very small range, one of the most restricted of all snakes, limited to Southern Ontario around the lower great lakes south to Indiana and Ohio. Ontario accounts for approximately 16% of its global range, which is largely limited to the Windsor and Sarnia regions.
Age of sexual maturation is reached at 2 years and they will live on average 3 to 5 years in the wild. Mating occurs in April, triggered by warming temperatures as snakes emerge from hibernation. Rather than laying eggs, Butler’s gartersnakes are viviparous, meaning females give birth to live young. Females produce litters of 6 to 20 young born in mid-July to mid-August. The entire reproductive development occurs within the female’s body, with newborns birthed already independent and fully equipped to fend for themselves.
Butler’s gartersnakes face many threats in their small Ontario range, mostly associated with human activities that reduce habitat availability and quality. Urbanization results in habitat loss and fragmentation of remaining small populations. Road separate populations from one another and contribute to mortality from vehicle strikes. Additional threats to Butler’s gartersnakes include intentional killing by people, and illegal collection for the pet trade. The combination of these threat, coupled with the isolated nature of remaining colonies in Ontario, has resulted in an ongoing decline in the Canadian range of the Butler’s gartersnake as local populations are extirpated.
The federal Recovery Strategy for the Butler’s gartersnake focuses heavily on habitat protection, restoration, and threat mitigation, along with monitoring of populations and increasing public awareness. Recommended actions include implementing best management practices, establishing long term monitoring, public outreach and education. The Ontario Provincial Government Response Statement’s actions include the need to conduct research to determine the effectiveness of threat mitigation techniques, recovery approaches and best management practices, including techniques for salvage and translocation.
In 2021, WPC was asked to lead the creation of a provincial recovery implementation team for the massasauga. The techniques we’ve been developing for massasauga rattlesnakes are also helping another endangered species on the Ojibway Prairie: Butler’s gartersnake. These reptiles face many threats in their small Ontario range such as urbanization resulting in habitat loss and fragmentation, roads separate populations from one another and increase the risk of vehicle strikes and people kill them or illegally collect them as pets.
We work to protect the Butler’s gartersnake from threat by supplementing wild populations and perfecting conservation techniques.
In 2023 we plan to have:
Butler’s gartersnake is on Wildlife Preservation Canada’s priority list for potential future action. Find out how we are currently saving other Canadian reptiles and amphibians, and how you can make a difference.
If you encounter a Butler’s gartersnake, report the sighting with a photograph to help document population distribution (Ontario NHIC, or inaturalist). Protect Butler’s gartersnakes and their habitat on your property by maintaining wet meadows, avoiding pesticide use, installing brush or rock piles, and keeping your cats indoors.
Q: Why is Butler’s gartersnake endangered if it tolerates urban areas?
A: While the species can survive in fragmented urban and suburban habitat patches with high densities of earthworm prey, this tolerance comes with serious risk. Large Populations can be eliminated overnight when land is bulldozed for development. The snake’s sedentary nature means it won’t cross large stretches of unsuitable habitat to find new areas, so fragmented populations become isolated and vulnerable.
Q: How does a worm specialist snake differ from other gartersnakes?
A: Butler’s gartersnake’s diet of primarily earthworms shapes everything about it; its smaller size, its preference for wet grasslands with rich soil, and its specialized feeding behavior. The Eastern gartersnake, in contrast, is a generalist that eats most small prey it encounters and can be found in a wider variety of habitat types. Butler’s gartersnakes are locked into earthworm hunting, which makes them dependent on specific habitat conditions and limits their ability to adapt to changing environments.
Q: Do road deaths really threaten such a small, shy snake?
A: Yes, significantly. Butler’s gartersnakes are most often found dead on roads in late summer and fall (Aug to October). For a small, fragmented population, even modest roadkill numbers can be catastrophic since the snakes won’t recolonize from elsewhere.