The Bronze Frog, (a subspecies of the northern green frog) is becoming quite common in the Pacific Northwest. On Vancouver Island, it is considered an invasive species and should be considered a serious threat to our indigenous frog species.
This frog is a small to medium size frog that can reach up to 10 cm in length. The frog gets its name from the coloration of its skin, they are a bronzy color. They have a white-spotted belly and a dark green color to their upper head and back areas. The males will often have a yellowish throat area.
Being true frogs, they have completely smooth skin and quite large ear discs located on the side of their heads, these ear discs are much larger than other frogs. Their eyes are gold.
The bronze frog feeds on a diet of worms and bugs that are small enough to swallow. They will also eat other smaller frogs and tadpoles. They have plenty of predators that eat them as well, this includes many types of birds and small mammals such as raccoons, mink, and ermine. I am not sure how predation is on Vancouver Island, but the fact that l am seeing more of these frogs all the time, l would have to guess that there are few predators here that actively feed on the bronze frog.
The bronze frog breeding season starts in the early spring and runs through most of the summer. The female frogs can lay between 2,500 and 4,500 eggs in a season, these eggs are distributed in small clumps on underwater vegetation.
Within a few weeks, the small eggs hatch out into tadpoles, they soon morph into frogs. They will reach sexual maturity at about one year of age. In the wild, bronze frogs can live up to 12 yrs of age.