Two Interconnected Grassland Mammals You May Never Have Heard Of
Species #1: The Black-tailed Prairie Dog
The Black-tailed Prairie Dog (Cynomys ludovicianus) is so rare in Canada it is only found in one place in Canada: Grassland National Park. The prairie dog was first documented in Canada 1938, when the first prairie dog “towns” were discovered. The nearest colonies are in Montana over 20 kilometres away — way too far for breeding between populations. There is thought to be about 3.6 adults in every hectare, and 12.6 juveniles in every hectare of grassland. This is not a lot of prairie dogs! In simpler terms, the number of prairie dogs are estimated to be between 6,000 to 9,000.
Historically, this species would have been considered a keystone species as it is a food source for species such as Swift Foxe (Vulpes velox), Ferruginous Hawk (Buteo regalis), Swainson Hawk (Buteo swainsoni), Prairie Falcon (Falco mexicanus) and Golden Eagle (Aquila chrysaetos). Their numbers have declined by 22 to 33 per cent over the years to the point that they cannot really be considered keystone. While the exact cause for decline isn’t fully understood, they are known to be susceptible to fleas, lice and ticks and prone to the zoonotic disease, sylvatic plague (bubonic) that these species can carry.
Despite no longer being a keystone species, their burrows do provide homes for Greater Short-horned Lizards (Phrynosoma douglassii) (another poorly known species), Prairie Rattlesnakes (Crotalus viridis), Burrowing Owls (Speotyto cuicularia) and Mountain Plovers (Charadrius montanus). So, they do continue to provide an important habitat service in Grasslands National Park.
But the story gets more complex. There is a unique predatory-prey system with two species at risk: the prairie dog and the Black-footed Ferret.
Species #2: Black-footed Ferret
The Black-footed Ferret is another grassland mammal that disappeared from Canadian grasslands in 1978. This species is nocturnal and an obligate carnivore — meaning it relies on a specific prey item, the prairie dog. This strange looking creature was lost due to the decline of prairie dogs, loss of grassland habitat, poisonings and sport shootings. Black-footed Ferrets also use the burrows of prairie dogs to give birth and raise their young.
Captive breeding programs for Black-footed Ferrets have been underway by Conservation groups like the Toronto Zoo for many years. The Black-footed Ferret recovery team has released 269 ferrets to Grasslands National Park since 1992. Calgary Zoo’s Wilder Institute has also been involved and released individuals in 2018.
Interconnected Survival
The Black-footed Ferret relies on a unique habitat and a very specific food source: thus, the number of prairie dogs will determine their ultimate success. If there are no prairie dogs, there are no Black-footed Ferret. Many other grassland species would be impacted as well.
The future of the Black-footed Ferret is unclear. The last Black-footed Ferret seen in the area was in 2013 and experts say there is strong evidence that it no longer exists in the wild. However, we can be hopeful that the efforts of Grasslands National Park to improve the habitat and prairie dog population so to release more captive ferrets that are ready and waiting to go home.
Grassland species have very intricate interspecies relationships, and thus conserving grassland habitat is vitally important to their survival.
To get a better sense of the landscape of Grassland National Park, check out the live webcam here.
Learn more about the work the Canadian Wildlife Federation is doing to help Canada’s native grasslands >
Tracey Etwell
Tracey Etwell, M.Sc, CERP, is a Restoration Ecologist with the Canadian Wildlife Federation. She supports the Rights of Way program helping restore pollinator meadows for Monarch Butterfly and other pollinators in eastern Ontario.
3 comments
Thanks for the excellent explanation of the interdependence between populations of the Black-
tailed Prairie Dog and the Black-footed Ferret.
Can anybody help the Prairie dogs in winnipeg,manitoba ?Losing home again by human rights Museum
They were poison once
Now the city wants to put stones on there home
Hi Darlene
Here is a statement we drafted for the use of Strychnine to control Richardson’s Ground Squirrels.
CWF DRAFT Policy Statement: Strychnine Regulation and Use as Pest Control
Introduction/Background
· In response to pressure from the provincial governments in Alberta and Saskatchewan, the Federal Health Ministry, Pest Management Regulatory Agency (PMRA) has lifted a 2-year ban on the use of strychnine to kill Richardson’s Ground Squirrels (RGS; aka gophers) in advance of what has been predicted to be a year of strong gopher population growth due to persistent drought conditions.
· It is deployed in as a coating on a grain bait that will attract RGS, resulting in their death when the coated grain is consumed.
· Research is scant and divided on the impact that RGS have on crops (Reference 1). Some have found that actual damage is proportional to that perceived by producers (Reference 2-4). There is no consensus possible on real pest effects other than they are usually local and episodic(Reference 5).
· There are multiple, interacting factors that contribute to RGS outbreaks including vegetation density, predator control, climate, and overall on-farm crop management practices(Reference 6).
· Strychnine use has a long history in agriculture pest control, but is an indiscriminate poison that has been shown to affect non-target animals, including species at risk such as badgers and birds of prey(Reference 7).
· An alternative to strychnine, zinc phosphide is a safer alternative to RGS control though poisoning and is available in Canada. It has been shown to be slightly less effective, more expensive, and more difficult to deploy(Reference 8).
· Zinc phosphide has been used for several decades as an alternative to strychnine. It is effective and has comes with much lower (but not zero) risk of secondary (predator/scavenger) poisoning and can affect non-target species. It is not persistent in the environment(Reference 9). It kills by causing organ cell death through phosphine toxicity. It can also cause physical distress(Reference 10).
· Last year, the Saskatchewan Wildlife Federation offered free, lethal RGS control using volunteer hunters who have registered to provide the service. This is considered a more humane control method. Todd Smith, the SWF Executive Director was quoted in an online source (https://www.discovermoosejaw.com/articles/strychnine-reintroduction-draws-cautionary-response-from-saskatchewan-wildlife-federation) saying “ ‘The issue with strychnine, though it is very effective, it has residual effects. If it’s applied correctly and the gopher dies underground, that would be ideal. But we know that’s not always the case,’” warning that carcasses consumed by hawks, owls, or other mammals could lead to unintended deaths among non-target species.
· The Alberta Wildlife Federation has not commented publicly.
· Strychnine is a neurotoxin that kills RGS by inducing seizures and muscular convulsions. The resulting stiffness is extremely painful for the individual, and the Canadian Veterinary Medical Association (https://www.canadianveterinarians.net/about-cvma/latest-news/concern-over-temporary-lifting-of-ban-on-strychnine/) considers it an inhumane method of killing animals.
· Used properly (correct dose and use of fresh poison) strychnine controlled more than 70% of ground squirrels in field trials(Reference 11-12).
Key Issues
· Strychnine also affects non-target species including animals that eat the poisoned bait (granivorous birds, rodents, cattle), predators/scavengers or domestic pets (cats, dogs) that eat the carcasses of poisoned animals(Reference 7). Efforts to limit the effect to the target species (RGS) have been unsuccessful leading to the conclusion that non-target species deaths are inevitable when strychnine is used(Reference 13). There are many studies demonstrating non-target effects across North America.
· The lifting of the strychnine ban has been widely condemned by wildlife conservation organizations in Canada but is broadly supported by agricultural producer groups and the Alberta and Saskatchewan provincial governments.
· Our AB and SK affiliates have not publicly opposed the lifting of the strychnine ban but issued warnings and offered alternatives. It is likely that producers who work with CWF directly and indirectly, use poisons to control pests or support their use, although we have not confirmed that.
· The 2024 total strychnine ban took 32 years to implement, beginning with restrictions and deregistration during the 1990s. This long process did not prevent political pressure resulting in its temporary reversal in 2026. Even if the ban is reinstated, future reversals under pressure from producers and provinces are possible and likely.
Proposed Solution:
· Oppose the lifting of the strychnine ban. Insist that the PMRA continue to regulate and restrict its access in Canada.
· Promote Integrated Pest Management
o This is long-term thinking, regional planning, and above all education.
o Takes advantage of scientific knowledge to prevent the environmental conditions that allow pests to flourish. It promotes the conservation of food webs to do their job to limit pest outbreaks through processes like natural predation.
o Uses non-toxic alternatives to hazardous chemicals like strychnine and neonicotinoids to manage pest outbreaks.
o Engages government programs to compensate producers for losses when uncontrollable conditions, like droughts, arise.
o It recognizes the value of non-chemical, manual pest control like trapping and hunting. And, under extreme cases, Integrated Pest Management uses toxic, but effective, control in well regulated and supervised settings to control rare and unanticipated pest outbreaks. But this should be the exception.
· Develop outreach materials that describe Integrated Pest Management and explaining why CWF is opposed to strychnine bait use as a pest control method.
· Prepare a press release, social media, and web page content describing the issue and CWF response to strychnine ban lifting.
· Work with affiliates to develop a consistent policy and statement around strychnine use.
Literature Cited
1. Marsh, R. E. Historical review of ground squirrel crop damage in California. Int. Biodeterior. Biodegrad. 42, 93–99 (1998).
2. Johnson-Nistler, C. M., Knight, J. E. & Cash, S. D. Considerations related to richardson’s ground squirrel (Spermophilus richardsonii) control in Montana. Agron. J. 97, 1460–1464 (2005).
3. Kincaid, A. T. A study of attitudes pertaining to the Richardson’s ground squirrel. (University of Lethbridge, Faculty of Arts and Science, Lethbridge, AB, 2003).
4. Newediuk, L. J., Waters, I. & Hare, J. F. Aspen parkland pasture altered by Richardson’s Ground Squirrel (Urocitellus richardsonii Sabine) activity: the good, the bad, and the not so ugly? Can. Field-Nat. 129, 331–341 (2015).
5. Proulx, G., MacKenzie, K. & MacKenzie, N. Distribution and relative abundance of Richardson’s ground squirrels, Urocitellus richardsonii, according to soil zones and vegetation height in saskatchewan during a drought period. Can. Field-Nat. 126, 103–110 (2012).
6. Proulx, G. Factors contributing to the outbreak of richardson’s ground squirrel populations in the Canadian prairies. Proc. Vertebr. Pest Conf. 24, 213–217 (2010).
7. Cowan, V. E. Strychnine poisoning in nontarget species in western Canada: A retrospective case series (2014 to 2023). Can. Vet. J. 66, 168–176 (2025).
8. Proulx, G. Evaluation of strychnine and zinc phosphide baits to control northern pocket gophers (Thomomys talpoides) in alfalfa fields in Alberta, Canada. Crop Prot. 17, 135–138 (1998).
9. Eason, C., Ross, J., Blackie, H. & Fairweather, A. Toxicology and ecotoxicology of zinc phosphide as used for pest control in New Zealand. N. Z. J. Ecol. 37, 1–11 (2013).
10. Gervais, J. A., Luukinen, B., Buhl, K. & Stone, D. Zinc Phosphide/Phosphine General Fact Sheet. npic.orst.edu/factsheets/znpgen.html (2010).
11. Proulx, G. et al. Strychnine for the control of Richardson’s Ground Squirrels: efficiency and selectivity Issues. in Proceedings of the Vertebrate Pest Conference vol. 24 125–128 (University of Callifornia, Davis, CA, USA, 2010).
12. Bourne, J., B., Roy, L., D., Hiltz, M., Merrill, P., N. & Hoffmann, W. Strychnine baits to control Richardson’s ground squirrels: an old story, a new twist. Proc. Vertebr. Pest Conf. 20, (2002).
13. Proulx, G. Field evidence of non-target and secondary poisoning by strychnine and chlorophacinone used to control Richardson’s ground squirrels in southwest Saskatchewan. in Patterns of Change, Learning from our past to manage our present and conserve our future 128–134 (PCESC, Winnipeg, MB, Canada, 2011).