This past week the annual Western toad migration began again at Lost Lake Park. Tens of thousands of these tiny toads gradually emerge form the lake to travel to the surrounding forests, though less than one per cent survive the journey.
Western toads are found west of the Rockies between Mexico and Southern Alaska. They will have three different habitats throughout a year: shallow bodies of water during spring breeding season, terrestrial forests and grasslands in the summer, and underground dens for winter hibernation.
The adult toads will migrate to breeding sites in early spring to mate and lay eggs. One female can lay between 12,000 and 16,000 eggs. They will then quickly hatch and become tadpoles in three to twelve days. The speed of their development is highly dependent on the temperature of the water. In six to eight weeks these tadpoles will then develop into dime-sized, terrestrial dwelling toadlets. This is when their treacherous journey begins.
By the end of the summer the toadlets will leave the water to join their adult counterparts in the forests and grasslands. During this life-stage they are easy prey for garter snakes, birds, small mammals and even other amphibians. They are also easily trodden on because they are so small and well camouflaged.
Once they have reached their destination, they will hibernate for the duration of winter, usually using existing animal dens or making their own. It will take two to three years for these toads to mature, and they can live ten years or more, continuing this cycle throughout their lifetime.
Lost Lake is home to the largest population of Western toads in Whistler. It is unfortunate for the toads that it is one of the most popular beaches in Whistler; however, it creates an amazing opportunity for people to see and understands this process firsthand. The migration takes two to four weeks, and environmental technicians and volunteers will be on side to direct pedestrians and vehicle traffic, as well as monitor and help the toads cross safely. Anyone in the park during this time is encouraged to use caution when walking and to get off their bike when travelling on the trails near the park and the beach entrance.
Though Western toads are considered relatively common in BC, it is expected that there will be population declines in southern BC as the species has been disappearing in wide ares of their historic range in the US. This is believed to be a result of a number of factors, the greatest of them being habitat destruction due to development in and around wetlands. Other causes include rising temperatures, increased UV radiation, and changing water levels due to climate change, traffic on roads and pollution. The province in monitoring their habits and tracking populations to learn more about how to support this sensitive species.
They are on the provincial yellow list, which means that they are considered a species of conservation concern, and they are a protected species under the BC Wildlife Act.
By Teah Schacter. Teah is a summer student with the Whistler Museum’s Discover Nature program at Lost Lake. She recently graduated from Whistler Secondary School and will be attending university in the fall.