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p. You might want to read “Part 1(The first part of this story, obviously)”:http://www.rousette.org.uk/mt-static/blog/archives/000549.html before you start this entry. Or perhaps you don’t like linear narratives, in which case, read them in any order you like.

p. The other main activity on our field trip was small mammal trapping and radio-tracking. One of the best ways of estimating the population of animals that spend much of their time hiding, or being otherwise rather inaccessible, is a ‘mark-recapture’ scheme. The theory goes something like this:

• you set out your traps on a grid of known area and check them regularly for animals (all the traps are filled with warm bedding and food so that the trapped animal has a pleasant stay in the trap hotel)
• when you catch an animal, you mark it (in our case by carefully clipping an small patch of fur in a unique pattern)
• at the end of your trapping period, you put the total number of animals trapped, the number of animals you marked, and the number of recaptures into a “big, scary equation(see near the bottom of the page for the equations)”:http://srmwww.gov.bc.ca/risc/pubs/tebiodiv/hares/hacoml20-05.htm
• what you should end up with is some estimate for the population size in that area

p. This is all well and good, but our grid of traps was laid out on a 45° slope. All we could use to grapple our way up this slope were the wild garlic plants growing there. I can’t recommend wild garlic as a secure anchoring point, and if you add in the additional difficulty of holding on for dear life to the garlic with one hand, and holding a trap containing a small rodent with the other, it becomes very tricky indeed. We also had to go through this procedure very early in the morning, which meant that we went in for breakfast reeking of garlic. Then there was the ‘Rodent Roulette’…

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