Taylor’s Fisher Frenzy

An inquisitive fisher plays around with a non-invasive sampling box.

Before joining the Snapshot crew, I worked on a long-term fisher (Pekania pennanti) monitoring project in a beautiful section of Northern California, called the Klamath-Siskiyou eco-region.

Our study focused on one of two endemic populations of fishers on the West coast found in Northern California and Southern Oregon. Fisher populations declined in the 1800s and early 1900s due mainly to trapping and habitat loss. This study was undertaken 11 years ago in response to a petition to list the fisher as a federally endangered species (which was ultimately overruled).

The goals of the project are to better understand the size and robustness of the western fisher population, explore species interactions between meso-carnivores (such as gray fox and ringtail), and investigate fisher responses to wildfires. It’s a very dynamic and exciting project to work on, with lots of valuable questions to explore.

The red X marks the location of our study area within the fisher’s historical and current range.

We used baited, corrugated plastic boxes at 100 historical locations to track our fisher populations. The boxes were fitted with a metal track plate covered in contact paper and ink, along with a glue strip that caught hair from critters passing through the box.

An example of a fisher paw print compared to my hand. Tracks of fisher, gray fox, spotted skunk, ringtail, and other species were used to calculate occupancy estimates. Hair samples were used to calculate fisher density throughout the study area.

Every day for three months, my co-worker and I would set off into the woods to collect track plates and hair snares.  This usually meant 10-12 hour days of driving around the Klamath National Forest, punctuated by steep hikes to retrieve samples in the forest.

The Klamath-Siskiyou eco-region has one of the highest diversities of conifers in the world. The area is marked by steep, rugged terrain and deep, river gorges.

Even though we never outright saw the feisty fishers, we began to expect “visits” from them at our boxes. We collected tracks and hair from the same boxes every week. The fishers certainly appreciated the chicken and cat food we left as bait for them! Our weekly box checks became like meeting up with old friends. At one site, I collected a female’s tracks and hair every week for two months. She never made a mess of the bait or destroyed the box (which I greatly appreciated)!

All in all, I had a terrific experience that helped me to understand the importance of non-invasive sampling (i.e., sampling that does not require capturing animals – like the camera trap method used in Snapshot Wisconsin)!

If you are still curious about the non-invasive sampling boxes, check out this video of the box setup.