There are 3 species of toads and frogs in the Houston area of British Columbia.
1. Western toad (Bufo boreas). Does not have a mating call but will squawk a bit if you pick them up and they are agitated. According to Green and Campbell (1984) the males do have a mating call in some regions (e.g., Alberta) but not in BC.
2. Spotted frog (Rana pretiosa). Males have a breeding call and start calling very early in spring. Their call is low pitch and not very loud, more along the lines of quiet grunts. Hence, their calls do not carry long distances. You do not get the din that is so delightful with some of the other species in Canada.
3. Wood frog (Rana sylvatica). Males call early in spring during their mating season.
A good book for BC amphibians is Green, D. and R.W. Campbell. 1984. The amphibians of British Columbia. BC Provincial Museum Handbook 45. Prov. of BC, Victoria. I think this book has been revised and the new edition may be available.