Millions of plump tadpoles appear — clouds, Hohn calls them — moving en mass in their remarkable daily migration from the depths of the lake to its oxygen-rich shallows where they feed on algae to support the metamorphosis to western toad.

The Royston-based filmmaker and expert diver spent four years filming the tadpole’s incredible daily journey, between June and July, and this fall released Tadpoles: The Big Little Migration, a mini documentary on this crucial phase of life for the toad, a designated threatened species in British Columbia under constant threat from urban development, logging and vehicle traffic.