Thursday, February 19, 2009

Oxbow Tracking Walk - Feb. 18, 2009

During Wednesday's walk at the Oxbow, Susan and Dan found evidence of deer, rabbit, otter, mink, mouse, and of course, the ubiquitous squirrel and beaver. We were baffled by some fisher-like tracks that seemed to begin at the water's edge. Were they actually those of an otter? No slides in evidence at that location. We were left scratching our heads on that one.

We do feel that we may have solved one mystery, though. We saw three or four melted-out tunnels similar to the one in the upper left of the photo - approximately four inches across, some going on for several feet, and all originating at water's edge or a hole leading to water. The tracks coming out of the hole, in the upper right of the photo, are clearly those of a mink. Do mink routinely use lengthy snow tunnels in the winter? I found quite a few references to mink tunnels on the internet. Could muskrat be involved? Maybe, though I couldn't find anything definitive about their use of snow tunnels. The other interesting thing about the scene captured in this photo was the presence of a single mussel shell at the hole entrance. It doesn't show up in the picture, but it was just inches away from the front of the hole. More evidence that mink are snarfing up those fine Nashua River mussels.

1 comment:

  1. It wouldn't surprise me at all if a mink made a long tunnel like that. That snow was quite soft just a while back, so very conducive to tunneling.

    Weasels do a lot of that, actually do a lot of "subnivian" hunting. (This is probably why they have evolved that long skinny shape. They can access their hidden prey, voles and mice, under the snow, where they themselves stay hidden. The trade off is, of course, a large surface area to volume ratio which causes them to lose heat quickly.)

    Other mustelids have that tunneling tendency. I think I mentioned, Susan, that I once observed two captive river otters in snow for quite awhile. They poked and probed, almost tunneling but not quite, as they played in the snow. They catch most of their prey in the water, so I had the impression that maybe this was a vestigial behavior of sorts, a behavior that might have been more useful to an ancestor but is no longer very useful to our modern otter.