Sunday, January 20, 2008

Mole Tracks!

Tracking club was very wet yesterday. Out at the sandbar a lot of our tracks were being quickly worn away as we studied them. Still it was a good day there - we found many species with some nice clear tracks (at least before it started raining). Our group was small and with the rain we decided to go somewhat quickly through the tracks there and then stop under the bridge on our way back.

While we were looking for tracking stations before tracking club got started we noticed some mole hills and tunnels. The story in our tracking community seems to be that protruding tunnels = coast moles (Scapanus orarius) and large mounds = townsend moles (Scapanus townsendii). Sometimes we find areas where there are several mounds and tunnels. What then? This is a subject that probably needs some more investigation.

Anyway as we were driving down to the bridge Dave and I discussed this a bit as well as about finding mole tracks. Apparently the spring dispersal is a decent time to find mole tracks as they are kicked out of their homes by mom and have to go find someplace new. It is a bit early in the year for that though. However, as I was looking at tracks under the bridge I noticed a pattern that seemed similar to what I had heard described and had seen pictures of as mole tracks (I had never seen them in person). Excited, I called over a couple other station leaders to confirm and all were surprised and in agreement that they were indeed mole tracks.

I haven't found much in the literature about differentiating moles by their tracks, so I don't have any good idea which species it is. One possibility I've thought of (though I have no idea if it is at all reasonable) is that the mole was out for the breeding season. Peterson's Field Guide for mammals says that male coast moles are in breeding condition in late January and townsend moles in February. Based on those dates if my theory is true it would seem to be a coast mole. However those dates are not too far apart and I would expect there to be a lot of regional and year to year variation in breeding dates.

(You should be able to see the tracks a lot better in the first and last picture if you click to enlarge them.)

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