Species Profile

Butler's Gartersnake

Scientific Name: Thamnophis butleri
Other/Previous Names: Butler’s Garter Snake
Taxonomy Group: Reptiles
COSEWIC Range: Ontario
COSEWIC Assessment Date and Status Change: November 2010
COSEWIC Status: Endangered
COSEWIC Status Criteria: B2ab(i,ii,iii,iv,v)
COSEWIC Reason for Designation:

Most populations of this species occur in small, scattered habitat remnants. Most are isolated so they are threatened by the negative genetic effects of small population size and by demographic stochasticity. Recent surveys have not detected the species at several sites where they were formerly known. Road mortality, ongoing habitat loss and fragmentation are also threats to this small specialized snake.
COSEWIC History of Status Designation: Designated Special Concern in April 1999. Status re-examined and designated Threatened in November 2001. Status re-examined and designated Endangered in November 2010.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | National Recovery Program | Documents

Image of Butler's Gartersnake

Butler's Gartersnake Photo 1

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Description

Butler’s Gartersnake (Thamnophis butleri) is a small, non-aggressive gartersnake with three distinct longitudinal yellow stripes on its dark brown back. This snake was first described in 1889 by E.D. Cope. Like most other small Canadian snakes, this species has been poorly studied. It is often confused with two other Thamnophis species coexisting in its range, the Eastern Gartersnake, T. sirtalis, and the Eastern Ribbonsnake, T. sauritus. Butler’s Gartersnake, however, is shorter in total length (38-51 cm), is much more docile and possesses a unique pattern and position of side stripes. The latter facilitates its identification. (Updated 2017/05/30)

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Distribution and Population

Butler’s Gartersnake has one of the most restricted global distributions of any snake in North America. This distribution is patchy and confined to southwestern Ontario, and parts of four U.S. states in the Great Lakes Region (Wisconsin, Ohio, Indiana and Michigan).In Ontario, it occurs in western Essex and Lambton counties from Amherstburg to Errol with disjunct locations at Skunk’s Misery (Lambton and Middlesex counties), Parkhill (Middlesex County) and Luther Marsh (Dufferin and Wellington counties). The Canadian distribution of Butler’s Gartersnake occupies approximately 16% of its global distribution. (Updated 2017/05/30)

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Habitat

Characteristic habitat of Butler’s Gartersnake includes old fields, disturbed sites, urban and industrial sites and Tallgrass Prairie. Essential habitat components include a dense cover of grasses or herbs with a heavy thatch layer and an abundance of earthworms as prey. This snake can be found near small bodies of water (including seasonally dry marshes and swales) in a small number of vacant urban lots (including industrial lands) and parks and in Tallgrass Prairie remnants. The species is difficult to find in its preferred habitat outside of the mating season and is then more frequently observed under rocks and debris. Although overwintering sites have not been directly observed in Canada, it is assumed that this snakehibernates in small mammal burrows, ant mounds, loose fill and/or crayfish burrows. Habitat loss has occurred in the Windsor-Sarnia region in the last 3 decades due to urbanization and agriculture. Skunk’s Misery has lost T. butleri habitat due to agriculture and forest succession, whereas habitat at Luther Marsh may have increased. (Updated 2017/05/30)

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Biology

In southwestern Ontario, Butler’s Gartersnakes generally are active from April to October. Mating occurs in early spring and 8-10 young are born live from June to September. Sexual maturity is estimated at 2 years and generation time is estimated to be 4 years. This snake feeds primarily on earthworms, which raises some questions as this food source did not occur in its current range until after European settlement. Predators of Butler’s Gartersnake, although unrecorded, are presumably the same as those of other Thamnophis species. The majority of Butler’s Gartersnakes in a population exhibit fairly limited movements. Maximum activity range is less than 1 ha and mean movement distance is 300 m. A small percentage of individuals have been observed moving much farther. (Updated 2017/05/30)

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Threats

The current disjunct distribution of Butler’s Gartersnake suggests a much wider historical range. Agricultural practices and increased urbanization are the major limits to the species and have contributed to the loss of most potential habitat of Butler’s Gartersnake in Canada. Available habitat is still decreasing and becoming more fragmented into small, isolated patches. This ongoing habitat loss and fragmentation are the major threats. Illegal collection for the pet trade probably occurs in some areas. This species is not commonly available in the pet trade, but is captured for personal collections. The severity of this threat is unknown. Multiple roadkill records exist in Ontario, but population level effects have not been assessed. (Updated 2017/05/30)

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Protection

Federal Protection

The Butler's Gartersnake is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Butler’s Gartersnake (Thamnophis butleri) in Canada
Status Final posting on SAR registry

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Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

10 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Butler’s Gartersnake Thamnophis butler in Canada (2011-09-09)

    Butler’s Gartersnake (Thamnophis butleri) is a small, non-aggressive gartersnake with three distinct longitudinal yellow stripes on its dark brown back. This snake was first described in 1889 by E.D. Cope. Like most other small Canadian snakes, this species has been poorly studied. It is often confused with two other Thamnophis species coexisting in its range, the Eastern Gartersnake, T. sirtalis, and the Eastern Ribbonsnake, T. sauritus. Butler’s Gartersnake, however, is shorter in total length (38‑51 cm), is much more docile and possesses a unique pattern and position of side stripes. The latter facilitates its identification.

Response Statements

  • Response Statement - Butler's Gartersnake (2011-12-08)

    Most populations of this species occur in small, scattered habitat remnants. Most are isolated so they are threatened by the negative genetic effects of small population size and by demographic stochasticity. Recent surveys have not detected the species at several sites where they were formerly known. Road mortality, ongoing habitat loss and fragmentation are also threats to this small specialized snake.

Recovery Strategies

  • Recovery Strategy for the Butler’s Gartersnake (Thamnophis butleri) in Canada (2018-12-06)

    The Minister of Environment and Climate Change is the competent minister under SARA for the Butler’s Gartersnake and has prepared this recovery strategy, as per section 37 of SARA. To the extent possible, it has been prepared in cooperation with the Province of Ontario as per section 39(1) of SARA.

Orders

  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Act (Volume 150, Number 21, 2016) (2016-10-19)

    His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, acknowledges receipt, on the making of this Order, of assessments conducted under subsection 23(1) of the Species at Risk Act by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) with respect to the species set out in the annexed schedule.
  • Order Amending Schedule 1 to the Species at Risk Act (volume 151, number 12, 2017) (2017-06-14)

    Biodiversity is rapidly declining worldwide as species become extinct. Today’s extinction rate is estimated to be between 1 000 and 10 000 times higher than the natural rate. Biodiversity is positively related to ecosystem productivity, health and resiliency (i.e. the ability of an ecosystem to respond to changes or disturbances), and, given the interdependency of species, a loss of biodiversity can lead to decreases in ecosystem function and services (e.g. natural processes such as pest control, pollination, coastal wave attenuation, temperature regulation and carbon fixing). These services are important to the health of Canadians, and also have important ties to Canada’s economy. Small changes within an ecosystem resulting in the loss of individuals and species can therefore result in adverse, irreversible and broad-ranging effects. List of Wildlife Species at Risk (referral back to COSEWIC) Order

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2010 - 2011 (2011-09-09)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.

Permits and Related Agreements

Consultation Documents

  • Consultation on Amending the List of Species under the Species at Risk Act: Terrestrial Species – December 2011 (2011-12-08)

    As part of its strategy for protecting wildlife species at risk, the Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, also called the List of Wildlife Species at Risk. Please submit your comments by February 8, 2012 for species undergoing normal consultations and by November 8, 2012 for species undergoing extended consultations.

Related Information

  • Environment and Climate Change Canada’s Species at Risk Act (SARA) Listing Plan 2016 to 2018 (2017-09-29)

    The status of wildlife species is assessed by an independent panel of expert Canadian scientists, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 149 terrestrial species were assessed as at-risk by COSEWIC between 2009 and 2016 and are eligible for listing under the Species at Risk Act (SARA) to be considered by the Governor-in-Council (GIC) on the recommendation of the Minister of the Environment: 86 species would be new additions, 54 currently listed species would be reclassified and 9 species would be updated to reflect changes in their recognized designatable units. A three-year listing plan has been developed to address all 149 terrestrial species and listing decisions for most species are anticipated by the end of 2018. Making amendments to Schedule 1 of SARA is a two-step process. The first step is for the GIC to propose an amendment through an order in council published in the Canada Gazette, Part I, for a 30-day public comment period. The second step is for the GIC to make a final decision on whether or not to make amendments to Schedule 1 of SARA, taking into consideration comments received during the 30-day public comment period. The amendments are made through an order in council published in the Canada Gazette, Part II. Both orders are accompanied by a Regulatory Impact Analysis Statement (RIAS) which presents the implications of listing the species or changing their status. Publishing this plan on the Species at Risk Public Registry is intended to provide transparency about the Government of Canada’s plan to make listing decisions under the Species at Risk Act. NOTE: The information presented below is intended to provide openness and transparency with respect to when terrestrial species might be considered for listing under Schedule 1 of the Species at Risk Act. It is intended to assist anyone who may wish to provide comments on such listing considerations. Given any number of factors can affect the timing of a listing decision; the Plan is subject to change. Accordingly, the Plan will be periodically updated.

Recovery Document Posting Plans

  • Environment and Climate Change Canada's Three-Year Recovery Document Posting Plan (2016-07-06)

    Environment and Climate Change Canada’s Three-Year Recovery Document Posting Plan identifies the species for which recovery documents will be posted each fiscal year starting in 2014-2015. Posting this three year plan on the Species at Risk Public Registry is intended to provide transparency to partners, stakeholders, and the public about Environment and Climate Change Canada’s plan to develop and post these proposed recovery strategies and management plans. However, both the number of documents and the particular species that are posted in a given year may change slightly due to a variety of circumstances. Last update December 2, 2021
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