26 October 2015

My First BFF . . .

. . . That's Black-footed Ferret, of course!  Last night I joined the Arizona Game and Fish Department on a spotlighting survey for Black-footed Ferrets.  This is the only ferret native to the Americas, and although it was once widespread in the inland western United States, it declined dramatically following US government efforts in the early 1900s to eradicate prairie dogs, its main food source.  In 1979 the Black-footed Ferret was declared extinct, but in 1981 a small population was found in Wyoming.  That population, too, declined rapidly and so by 1985 the entire remaining population, only 18 ferrets, was captured and brought into a captive breeding facility.

The recovery has been slow but steady, thanks to a successful captive breeding program, and there are now ferrets in the wild in 24 locations, totaling about 300 individuals.  Only a few of these populations are considered self-sustaining, including the population near Seligman, Arizona (although numbers have been dropping here in recent years, too).  The total population in Arizona is probably less than a few dozen now.  To help determine the health of the population, and the causes for decline, AZGFD recruits volunteers for four five-night trapping efforts a year.  I was able to join last night, excited to help such a cool endangered species, but also selfishly excited at the chance to see this rare and hard-to-find species in the wild.

Holly and Jennifer plan the night's surveys in the ferret processing trailer.
Before we even got all our gear ready for the night of sampling, one of the volunteers was returning to the ferret processing trailer with a Black-footed Ferret in a trap!  Of course, we stuck around for a few minutes to see and photograph it, in case we didn't come across any more that night.  When new ferrets are captured, they are immunized against several diseases, their health is assessed, and they are given a PIT tag so that they can be individually recognized in the future.  When the PIT tag of this individual was read, they determined it had been caught just one or two nights before, so it didn't need any further processing and was promptly released back at its point of capture.

Jennifer shows a Black-footed Ferret in one of the long live traps that the Arizona Game and Fish Department uses to catch the species.

Black-footed Ferret in a trap.

The plan for the night was to slowly drive up and down a network of rough dirt roads through known Gunnison's Prairie Dog colonies, each of us shining a spotlight on our side of the truck, looking for the glowing green eyes of a ferret.  Black-footed Ferrets have a distinctive bright emerald green eye shine that helps distinguish them at a great distance in the dark from other small mammals of the area like cottontails and jackrabbits.

Holly shines a spotlight into the prairie dog colony, looking for the bright green eyeshine that indicates a Black-footed Ferret.

We drove up and down one area for several hours, until about 2:00 AM, when we figured we had covered the area well enough and moved on to another area where a ferret had been seen but not caught the night before.  We were seeing lots of cool wildlife, like kangaroo rats, Common Poorwills, many Desert Cottontails and Black-tailed Jackrabbits, and even one American Badger.  But, by around 3:00 AM it started to feel like we were dragging, starting to get a little frustrated with having seen no ferrets other than the one someone else had caught.  Then, we spotted a Great Horned Owl on the ground near the road, kind of flopping around.  From a distance it seemed to me like the left wing was tucked in, and the right wing was outstretched and trying to flap.  It was near a barbed wire fence, so I was afraid it had hit the fence in flight and broken a wing.  But, as we got closer, we spotted a long furry tan tail with a black tip flipping about vigorously from under the bird.  The owl wasn't injured, it was trying to kill a Black-footed Ferret!  Holly opened the truck door and ran at the pair, yelling "No you don't, you f***er!  That's an endangered species!"  The owl dropped its prey and flew off into a nearby snag, and the ferret ran into a nearby burrow.  It seemed healthy when it ran, and it even popped its head out of the burrow a few times as we grabbed a trap and approached the burrow.  The best way to catch a Black-footed Ferret is to watch it until it goes in a burrow, and then place a live trap over the burrow entrance, temporarily plugging all the other holes.  So, we set a trap at the burrow and continued looking for other ferrets.

Holly secures burlap around the trap before positioning it at the entrance of the burrow.  This gives the illusion that the trap is just an extension of the burrow, and helps entice the ferret to enter.

Once the trap is in place, it is important to double-check that the opening is accessible from inside the burrow and that the trigger mechanism is properly set.

I was a bit too slow to get any photos of the dramatic ferret vs. owl fight, but the owl stuck around until after we set the ferret trap, scowling at us from this snag.

An hour later we came back to check on the trap, and the ferret was still not in it.  We were really hoping to catch it, not just for the regular processing that is essential for conserving the species, but especially because it was just in a wrestling match with a deadly predator, and might need some first aid or more thorough medical care.  We checked again an hour later, and the trap was still empty.  Again an hour after that, the trap was still empty, but this time it was starting to get light and we had to pack up the traps and head back to the headquarters to submit our data sheets for the night.  We were both a bit disappointed to not catch the ferret, and were left worrying whether it had sustained fatal wounds, but still were thrilled to be able to witness such a rare and dramatic moment!

1 comment:

Andrew Durso said...

Dang, I bet that owl was scOWLing at you something serious—you stole its dinner! I'm sure it was an easy choice for a ferret biologist, but I think I would have hesitated. I mean, predation happens, death is a part of life, and all that. Part of the reason we'd like to save BFFs is so that GHOW's can eat them. They are valuable at least partly for their ecological interactions, even when they die in the process of interacting. Of course there are way more GHOWs than BFFs out there.