Assessment of Potential Indicator Species for Monitoring ...

AMERICAN BULLFROG Rana catesbeiana
1a. Present in the Fraser Basin year-round?
Yes.
1b. Broad distribution?
No.
1c. Common in Fraser Basin?
No, occurs in the Fraser Valley as far up as Chilliwack (Orchard 1984).
1d. Proportion of diet within the aquatic food web.
Adults will eat anything including young birds, mice, fish and smaller bullfrogs.
Tadpoles are largely vegetarian but will scavenge carrion (Orchard pers.
comm.1994).
2a. Has the home range of the species been described?
No.
2b. Habitat selection is well documented?
Entirely aquatic and rarely leave the weedy heavily vegetated permanent ponds
and lakes that they inhabit. They are extremely wary during the day (Green and
Campbell 1984).
2c. Breeding biology is well understood?
Prolonged breeding season beginning in late spring and extending through the
summer. Males have a loud distinctive mating call (Green and Campbell 1984).
Eggs are laid in huge floating masses as much as 3 ft across. Tadpoles take four
years to mature (Orchard pers. comm. 1994).
2d. Migration behaviour is well documented?
Not documented.
2e. Information on historic abundance?
Species was introduced.
3a. Can nests or animal be easily located?
Yes, the males distinctive call should make locating breeding sites quite easy. Egg
masses should be highly visible. Tadpoles may be difficult to distinguish from
Red-legged Frogs until they have reached their maximum size when they are far
larger than any other species of tadpole in B.C. (Orchard pers. comm. 1992).
3b. Can samples be easily collected?
Yes (Orchard pers. comm.1994).
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