Tarahumara Frog Reintroduction

Tarahumara Frog recently reintroduced into a canyon in Santa Cruz County, Arizona.

Since I moved to Arizona a couple of months ago, I've shifted my job search strategy significantly.  Now that I'm limited to a certain area (which I love!), I'm focusing most of my effort on making local connections such as meeting local biologists, and getting myself and my expertise known through first-hand interactions.  A couple of weeks ago, I was having lunch with Tom Jones of the Arizona Game and Fish Department, and he put me in touch with Abi King, who runs the state's Tarahumara Frog program.  Abi was going to be releasing some captive frogs to the wild, and needed some help hiking them into a remote canyon.  I was excited at the chance to help this very unique species (and to meet some fellow biologists and frog lovers).

The Tarahumara Frog is a mostly Mexican species whose range barely enters the U.S.  It was once rather common in several of the southernmost canyons of Arizona.  In the 1970s and 1980s, the populations declined dramatically.  The cause for the decline is not well understood, but diseases, introduced species, and pollution have all been blamed.  About 350 were recently released into another canyon in southern Arizona, and about 500 or so were in captive breeding programs in the states.  That means that the 100 or so released by us constituted a little more than ten percent of the total U.S. population.

Beautiful landscapes of oak savannah on the way into the reintroduction site.

We started with a drive up a long, rough dirt road, through a couple of gates, and near the edge of a Wilderness boundary where we'd begin our hike.  The scenery was beautiful, and on the drive in I could tell we'd be surrounded by dramatic views for the rest of the day.  We eventually parked when the road was almost hard to see, and loaded the frogs into large frame packs.  The frogs had been treated for chytridiomycosis and placed in large tupperware containers with about 2-5 frogs in each container along with water and a paper towel.  We each loaded five or six containers into our packs, inside a pillow case to keep them shaded and cool.  (As the water splashed out through the holes in the tupperware, it wet the pillow cases, and the evaporation from the pillow cases kept the frogs from overheating.)  Then, we piled our personal gear on top of the sturdy frog boxes and strapped everything in for the hike.

Loading our packs with Tarahumara Frogs and our personal gear for the day.

The hike wasn't very long, maybe two miles, but it was pretty steep and mostly off trail.  There were lots of ankle-rolling rocks hiding in the dense grass, so it was a bit slow-going.  We took extra care on the way in because a fall that might only skin our knee or bruise our elbow could be lethal for our precious cargo.  There was plenty to look at as we worked our way across the side of one hill, and over and down the next into the canyon.

Hiking the frogs in through a beautiful landscape.

When we reached the canyon about an hour and a half later, I was thinking that even aside from the cool frogs in our packs, it was special to be in one of the last known sites for this species in the U.S.  The last known Tarahumara Frog in the United States had been found dead in this same stretch of canyon in 1983, only a decade after biologists estimated there were 500-700 of them here.  We had another short introduction to the protocol, and headed upstream a little further to start releasing frogs.

Heading upstream after a short introduction, ready to find some good frog pools.

We then spread the frogs out throughout a section of the stream that was maybe a quarter mile in length.  We placed the tupperware containers partially submerged in the stream, with a bit of stream water that we let flow in through the air holes, and usually with a rock on top to keep the container in place.  The containers had to sit for 20-30 minutes so that the frogs could acclimate to the change in temperature and water chemistry.  Then, container by container, we released the frogs into their new homes, taking lots of pictures along the way.

A container of Tarahumara Frogs acclimating to the thermal and chemical conditions of the stream.

Tarahumara Frog in its new habitat

With all the acclimation time and the difficult canyon walls to maneuver around, it took us until well after lunch to release all the frogs.  It was interesting to me to see how few of them we could find on the way back down the same stretch of canyon: although we released about 100, I think I only saw 10-15 on my return hike.  However, I was also in the middle of the group, so a bunch of the frogs had probably been visible but dove to the bottoms of their pools as the first couple of hikers passed by.

This was one of relatively few Tarahumara Frogs still easily visible at the edge of a pool on our return trip back down the canyon.

The hike out was, of course, tougher than the hike in: despite releasing all our frogs (and so carrying less weight), the frogs didn't weigh much in the first place and the return hike was all uphill.  There was a bit less pressure to get there quickly, though, since there was no risk of overheating the frogs on our backs.  So we took our time, periodically catching our breath from the steep climb, and checking out the other cool critters in the area.  We returned to the trucks in plenty of time to drive back to Tucson for a delicious dinner to celebrate an important job well done.

Hiking out at the end of a successful Tarhumara Frog release.