The Sub-adult Western toad migration in Ryder Lake is wrapping up for 2015. These tiny toads started migrating on June 22 this year which is the earliest migration since the Fraser Valley Conservancy (FVC) started monitoring this population in 2008. Local landowners also indicated that this is the earliest that the toads have started migrating (to their recollection). The Western toads took advantage of the warm weather to develop quickly from eggs to tadpoles to sub-adult toads (affectionately called “toadlets”).
Western toad tadpoles developing in Hornby Lake. Some are developing legs and getting ready to complete their metamorphosis.
Thousands of Western toad tadpoles gathering along the shore of the breeding pond. Some have even completed their metamorphosis and are emerging on shore.
The Fraser Valley Conservancy (FVC) completed 9 road surveys monitoring the toadlet migration this year. In 2014, 59 permanent survey plots were laid out every 50 meters along Ryder Lake, Elk View and Huston roads (in the vicinity of the breeding pond). We monitored the same plots this year and will be able to compare the results between the years. An initial review of the data shows that there were many fewer toads found per survey where the fencing and crossing structure was installed this year compared to the same locations last year. Further analysis of the data is required to accurately report on the migration and the resultant impact of the crossing structure.
We also used time-lapse photography to see how many toadlets were using the crossing structures. Photographs were taken every minute in several survey sessions and show hundreds of toadlets making their way through the culverts. We quickly analyzed 2 hours of data from June 25, 2015 and found over 3500 toadlets using one of the crossing structures (that’s an average of about 29 toads/minute)!
Toadlets using the existing culvert to cross under the road.
A minute later… More toadlets using the crossing structure!
The toadlets were also using the new crossing structure! Can you spot the tiny toads amidst the rocks and leaves?
There are at least 31 toadlets visible on their way safely to the other side of the road!
Tiny toads moving along the fence towards one of the crossing structures.
Environment Canada’s Habitat Stewardship Program funding has supported the FVC staff in their development and implementation of this project and have committed to continue to support our work in the years to come. We look forward to continuing to monitor the amphibians in the Ryder Lake community and will report further on the migration once we have had a chance to go over more of the data!