Mammals of Nova Scotia with Ms. Reginald

Day 4: March 28, 2013

Hi Kids,

My sad news for this morning is that we did the calculations from our mark and recapture studies and did not find happy news. Here is how the trapping played out: During the first day, we managed to capture 3 voles overnight in the traps. We then cut a little bit of their fur off (this was to mark them) and then we released them back into the wild and waited to see how many the same voles we might manage to recapture. Hence the method is called "mark and recapture". If there are many rodents in the field, then we would tend to recapture fewer of the original rodents we caught in the first place. And if there are only a few rodents around, the rodents that we would recapture would tend to be many more of the original rodents that we originally trapped and marked. Using a mathematical formula, we can estimate the number of rodents in the area. At the end of the second day, we did manage to trap 2 voles, but they were ones we had captured and marked earlier. At the end if the third day, we recaptured one of our original voles again. Using the mathematical formula, we calculated that there are 3 voles/hectare.

It's a vole. Look near its tail for the mark we made by cutting its fur.

All this sounds fairly simple, doesn't it? But, I have learned that you need to be a fairly hardy to do kind of work. We were out for around 8 hours straight, trudging around in the snow. Most of us learned that our boots aren't exactly waterproof anymore. But, I've been dressing in so many layers, that I'm managing o.k. It is also pretty hard to set out the traps. All the little traps are technically supposed to be laid out exactly 10 meters away from each other, to form a rectangle. But sometimes, trying to do this lands you in a stream. It's pretty hard to find a good spot to put down a trap. That's why experienced ecologists tend to capture more rodents. It's important to think like a rodent for this kind of work. I'm really glad that there are dedicated people who are doing this work to monitor the health of various populations of animals. This helps us know when action is needed to protect certain species.

Did we capture anything?

Mrs. Reginald

Challenge question for today:

Both mice and voles are pretty cute, but they do look a little  different. Mice have special adaptations so they can look for food in fields as well as in a forest. Voles stick to foraging for food in the forest. What are each one's special adaptations and how does this help them?