frogs

This past week, Monday – Friday, was my first proper tour of field work.  My job for this season is to survey and promote the growth of the population of Sierra Nevada Yellow-legged Frogs (Rana sierrae), an endangered species.  To put it more simply, I’m part of a frog crew that works in / around high country lakes.

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This past week, a crew of 7 went out to the field to take frog population surveys for 3 days.  For 8 – 10 hours each day (we repeated the survey 3 days while out in the field) we day-hiked through ponds and streams in teams of 2.  The task was to keep an eye out for any sitings of a Rana sierrae and then capture said frog with an amphibian net.  Once the frog is netted, the following steps took place:

  • Make sure you have control of the frog in the net (i.e. that he / she won’t hop out)
  • Scan the frog to see if he / she has a PIT tag
  • If he / she does NOT have a PIT tag and is over 40mm long (the length at which these frogs begin to exhibit sexual dimorphism) then give the frog a PIT tag
    • make a miniscule and harmless incision into the top layer of skin of the frogs back and then slide in a tiny PIT tag (a little thicker than mechanical pencil lead and the length of a tic tac), pushing it towards their rump once under the skin
  • If he / she does have a PIT tag ID that reads in the scanner, then move on to the next steps
  • Determine the sex of the frog
    • males tend to be smaller than females at maturity, but are best distinguished by the nuptial pad (a black, raised spot) on the base of their thumbs of their forelegs
  • Measure the length of the frog (in mm) using calipers
  • Weigh the frog by putting the frog briefly in a plastic sandwich bag and attaching the scale’s clip to the bag (see photo)
  • Mark the GPS coordinates of the frog’s location and note the health status of the frog
  • Re-release

All of this happens rather quickly, so the frog is under very minimum stress and is soon released again.

The day goes surprisingly fast, and it was amusing for me to consider how much time I’ve spent hiking avoiding getting my feet wet, and then in this case all week I was looking for water to hike straight through.

We even got a full day of rain out there, as in it rained steadily and with minimal breaks for over 24 hours (the “drought” in action?).  I had a pretty substantial puddle under my tent, but thankfully, no leakage.  Since rain makes it difficult to get a visual on these already-tricky-to-see & well-camouflaged frogs, a steady rain means you cannot survey for frogs.  So one entire day, we were not able to work.  That day I mostly read and napped in my tent, but got out when the rain lightened a bit to take some gloomy (my favorite) photos.

In summation, it was a great first full work week for me.

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