Western Toad Monitoring Project

The Squamish Environment Society has launched a citizen science project in collaboration with BC Parks, to monitor Western Toads (Anaxyrus boreas) at Alice Lake Provincial Park. The project aims to monitor the health of Western Toad populations breeding at Edith and Fawn Lakes, gain a better understanding of the factors that affect breeding timing and success, and mitigate impacts to toads from park users. Volunteers will conduct surveys on foot and by kayak during adult mating, tadpole development, and toadlet migration into the forest.

Amphibian populations everywhere are declining due to loss of habitat and climate change and western toads are a federal Species of Concern. We hope that engaging local residents in citizen science will encourage stewardship and increase awareness of this species at risk and that information gathered can be used to inform future planning objectives for BC Parks.

To get involved, please email info@squamishenvironment.ca

More About the Project

2019 is the first year of a multi-year project to monitor Western Toad breeding, tadpole development and toadlet migration at Fawn and Edith Lakes. The surveys aim to record mating ‘hotspots’ and timing, egg mass locations, tadpole numbers and rate of development, toadlet aggregations and migration routes and timing. Volunteers can sign up for surveys as their schedule permits. Incidental toad sightings from hikers on the Four Lakes Trail are also encouraged.

Western Toad populations are particularly vulnerable during the tadpole and “toadlet” life stages. Tadpoles congregate around shorelines where they may be impacted by wading humans and dogs. As the toadlets emerge from the lakes, they must cross trails that are busy with bikes and hikers. We hope that by better understanding how, where and when the breeding cycle occurs, that human impacts can be mitigated.

The project is modeled on other successful, collaborative projects, such as Kentucky-Alleyne, Ryder Lake, Lost Lake Whistler. Surveys conducted by SES volunteers on foot and by kayak, will take place from early April through September. Guidance and logistic support is provided by BC Parks, with additional expertise offered by PhD candidate Roseanna Gamlen-Greene, who is studying Western Toads on Haida Gwaii.

More About Western Toads

Western Toads use three different types of habitat: breeding habitats, terrestrial summer range, and winter hibernation sites. In spring, adult toads migrate from terrestrial areas to communal breeding sites in wetlands, ponds and lakes. Breeding often takes place over a period of less than two weeks. The smaller males clasp females from behind and fertilize the eggs as they are deposited. Male toads produce a quiet, twittering ‘release call’ if they are accidentally grasped by another male.

Once laid, the eggs quickly develop into tadpoles that hatch and swarm in groups of hundreds or thousands of individuals through the warmest, shallowest water available. By the end of the summer, the tadpoles transform into toadlets and leave the water. Dense aggregations of toadlets are often found hidden along the shore of breeding sites, and clustered in piles when the weather turns cool. At Alice Lake Provincial Park, toadlets migrate into the forest en masse and can be seen crossing the Four Lake Trails along ‘toad alley’ between Edith and Fawn Lakes. Male toadlets reach sexual maturity in 3-4 years, females in 4-6 years. Individuals may live for 10 years or more.

After breeding, adult Western Toads disperse into terrestrial habitats such as forests and grasslands and spend the summer and fall foraging in warm, low lying areas. Over the winter they hibernate in burrows below the frostline, up to 1.3 metres underground.


Photo: Stephanie Gervasin, courtesy Oregon State University. By CC BY-SA 2.0 licence.