Thursday, September 03, 2009

Snakes, Frogs and Polliwogs

This summer we've seen lots of polliwogs, big polliwogs, in the water around our cabin. These are not your normal, run of the mill polliwogs. These are mega-polliwogs that will grow up to be bullfrogs. Bullfrogs are not native in Powell Lake. They were imported to BC years ago by someone who thought it would be a good idea to "farm" them for their tasty legs. The farms didn't thrive, but the frogs did. Now they've spread across the Lower Mainland and the southeastern portion of Vancouver Island.

Bullfrogs may stay in the polliwog stage up to two years, feeding on algae and detritus in ponds and lakes. They can be seen swimming just under the surface, ruffling the surface much like a trout rising for it's evening meal. Right now there's an explosion of young frogs sitting on logs, rocks and our cabin floats. I know they are harmful to native frog species, but they are fun to watch. They seem to have no fear, staying put even when I walk nearby. But they better look out.

Right now we have lots of Common Garter Snakes hanging around. One of the top items on their menu is frogs. I wonder if there's a relationship here? Garter Snakes are excellent swimmers. They can negotiate a long stretch of water with just a few whips of their tails. And quick enough to overtake an unsuspecting frog, at least a young one. The BC Ministry of Environment website notes that the tables can be turned when it comes to larger bullfrogs. Garter Snakes have been found in their stomach contents. I guess turnabout is fair play as they say. -- Margy

5 comments:

  1. Our cool, rainy summer on Ontario has bred a raft of bugs, and subsequently many more predators and prey in the cycle of life. Our big bullfrogs eat the smaller frogs, as well as the smaller one's prey. Jeremiah, however, has disappeared. The heron may have gotten him!

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  2. Hi Margy, I just read your link to bullfrogs. They sound very aggressive I hope they don't mutate into giant monsters and take over the world (LOL).
    Your friend Betty

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  3. Oh man, did you have to mention swimming snakes??? Frogs I can deal with but snakes, yes even garter snakes, freak me out...
    But I guess there has to be a place for them in this big wonderful world, just with it wasn't Powell Lake.

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  4. Nice picture of the swimming snake.

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  5. We have polliwogs in our little pond this year for the first time. We have been waiting for them to grow and leave as we need to treat the pond for a snail invasion - they are clogging the pump. But our polliwogs don't seem to be growing up and leaving - after reading your post, we realize that they might be here into next year, too!

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