Monthly Archives: February 2012

Spinning in Circles

Yesterday we were able to get a little flight time in one of the CDFG’s airplanes (post picture). The flights are crucial in that we cover the entire study area (and beyond) far more quickly and efficiently than is possible on the ground. This allows us to find animals that have wandered into areas we don’t (or can’t) normally search. It also is a great opportunity to see the study area from a different perspective and that is often a very good thing.

Foothills from telemetry plane

The plane right before takeoff

The downside is that frankly I don’t much enjoy these flights. When we first began the project the prospect of flying in an airplane or helicopter looking for animals seemed extremely exiting. Well, that excitement wore out after about flight number two. A flight entails hours of listening to static over the ear phones. It is cramped and often it is either too hot or too cold. When you do hear something the pilot (who does a wonderful job but probably doesn’t enjoy telemetry flights all that much either) promptly turns sharply so we don’t “loose” the signal and then circles until we feel confident that we have a reasonable location on the animal. I’d like to tell you that I’m so tough that I’ve never felt the tiniest amount of motion sickness during all this, but I’d be a big liar! One out of every three flights I start feeling a little green somewhere along the way. Usually, this occurs when we’ve been doing circle after circle for about 3 hours.

Yesterday’s flight was a mixed bag. We found 14 animals (that’s about 30 circles) of 21 that I was looking for. You can get a rough idea of where animal are by looking for the circles on the included maps of our track logs. Unfortunately, the day was cut a little short because we detected a mortality signal of female 1E03E near Highway 36. Beings that this needed to be investigated we didn’t spend as much time searching for all animals as I would have liked. Additionally, this was “one of those flights” where I don’t feel too well by the end of it.

Track Log and Locations of Flight

Flight path while doing telemetry

Sadly, the day didn’t end any better because the mortality signal turned out to real (meaning there was indeed a dead animal). We  don’t know what killed this female but we are investigating possible causes like predation. Hopefully, we’ll know more soon. We probably would not have found this mortality without the flight – or at least not for a long time. So, despite any personal comfort problems that the flight present, they are extremely important for us to continue and get as often as we can.


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Today I found myself attempting a walk-in on one of our females.  When I estimated I was getting close (<50m) to where she was, I got out my binoculars and scanned the surrounding trees.  I have a bad habit of trying to guess what tree the fisher is going to be in before actually seeing the animal (and I am rarely correct).  I saw a tree about 30m ahead that looked good, so I headed that way.  After 10m, I stopped again to scan the tree with the binoculars to see if I could see her or any possible cavities/nests she might be in.  No such luck.

18871 at one of her dens in May 2011

Just then it suddenly began to rain.  I looked up to see a fine mist coming down.  The weather reports hadn’t mentioned a very high chance of precipitation today, but I’ve learned not to put much faith in any weather predictions of the study area.  At the same time I also noticed the distinct smell of fisher.  I figured I must be getting close…wait a minute…it’s not raining anywhere else…then it hit me…literally!  I looked up again to see a fisher tail straight above, and round two raining down on me.  I’d been scent marked!

The culprit of the sudden downpour was 18871, a three year old female.  This fisher was released in December 2010, had two kits in the spring, and has basically occupied the same area since shortly after release.  She was resting up in a nest at the top of a 40ft white pine.  Her behavior indicated she obviously wasn’t happy that I was close to her, but I wasn’t very thankful for the present either!  She was very vocal and moved through the canopy over to a tree further away before climbing down and making her escape. Since she seemed to be agitated by my presence, we will avoid any walk-ins on her for a while.

Anyway, thought you might get a kick out of today’s misfortunes.  I better go take a shower.



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On The Road Again

A lot of what we talk about and report on is our female fishers. I suppose there are a lot of reasons for that but a major one is that we usually track our females and most of our males wear Argos transmitters produced for us by Sirtrack. The great thing about these transmitters is that we don’t have go out and do the tracking. The location is estimated through overhead satellites that transfer the data to a processing center that then sends it to us in our email – what some have dubbed “armchair biology”. One of the really important reasons we put these on males is because they allow us to track fishers over long distances.

Male fishers have big home ranges compared to females and they seem to cover a lot of area. Here, I have included a figure that shows data that we have collected on 4 males from the last 3 months (not all our males are included here). You can see from the points that they do a pretty good job of staying away from home ranges of other males even when when they share a common border and have some overlap. Just for fun I included a visual representation of a Kernel Density Estimator for female fishers. Basically, the darker colors are where female fishers are found the most. As you might expect there is a some overlap between males and females, but some males are somewhat off by themselves. It makes sense the the biggest most dominant males have home ranges that include more female’s home ranges, but we are still testing this hypothesis.

The locations for 4 selected males

Yesterday Kevin described the frustration of not being able to find animals that “disappear”. The information we are getting from our Argos collars have been really informative with regards to showing us the fishers sometimes do seem to just go exploring. Just recently we have had two males that have seemed to wander away from their usual haunts. Had we been tracking these animals with regular VHF telemetry it is likely we would have just “lost” an animal for awhile until it eventually showed up again. We know females take these same types of trips, but I suspect we catch them in the act far less frequently.

If you look below at the two other figures  I’ve included you can see male 1 and male 4 have each recently taken petty significant jaunts. Male 1 only recently set out toward the east. He has covered about 10 miles in the space of about a week. The other male made about a 20 miles round trip over the course of about a month. Notice that he wandered right through the middle of one of those dark red areas – the home range of one of our females released in year 2.

What do these trips represent for a male fisher? Well, that is another thing we are still thinking about. Maybe they are checking out locations of females. Particularly with the breeding season fast approaching it may be useful for males to keep track of potential mates. Perhaps they are simply looking for an area that has higher concentrations of prey or maybe, like ourselves, they just want to see some place new once in a while.

Male 1 recent movements

Male 4 recent movements

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Disappearing Act

A few days ago Tati located one of our females, 1E003.  This normally wouldn’t be much cause for excitement, except this female had been missing for over a month.  After repeated searches of her home range during this time, we were beginning to fear that her collar may have failed.

IE003 in front of one of her dens last spring.

So where was she finally located?  Right back in one of the drainages she frequented during the last year of tracking her.

This phenomenon of fishers disappearing and reappearing is both interesting and frustrating.  Where do they go during these absences?  Do they make a journey to a far off place and then return, are they just in some hard to hear spot within their normal home-range, or is their collar not functioning properly?  This has happened a few other times over the last year.  Last fall one of our animals on the west side of the study area went missing for a little over a month before reappearing close to where she denned up the previous spring.  When a fisher goes missing, we spend quite a lot of time looking around for them, but due to rough terrain and our limited resources we cannot search everywhere.

So where do they go?  Your guess is as good as mine.

It’s good to know that 1E003’s collar is still functioning.  This was an animal that we were unable to trap over the fall, and so her VHF collar is only expected to survive a couple more months.  We are hopeful the battery will at least last until she has (with any luck) denned up and we document kits.


Rest site from Dec 2011.

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Snow Tracking

Last night a small storm dropped a few inches of snow in parts of the study area, and this morning I came across a fresh set of fisher tracks.  This winter’s mild weather hasn’t provided many good snow-tracking opportunities, so I decided to spend some time back-tracking this animal.

I really enjoy snow-tracking, as it allows you to see exactly what habitat an animal is using, how they are moving through the forest, and sometimes affords the opportunity to witness behaviors that are otherwise difficult to see (such as kill sites).  These tracks were in the area occupied by fisher 21392, a female born on Stirling and captured last October.  Though I am not able to confirm that the tracks belonged to her, they appeared to be heading down a drainage towards where I located her (via telemetry) today.

I thought I would share my GPS track-log from today.  In it I listed a few points along the way that were interesting to me.  The overall distance tracked was a little shy of two miles.  Not a huge distance by any means, but still very tiring because of the constant going in and out of drainages and the dense understory vegetation.


Track Pattern

Track Close-up

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The Depths of Despair

Fisher in Box (photo: Tati Gettleman)

Today Rob and I went and checked some traps that Kevin set and opened several days ago. Sadly, we caught nothing! We have adopted a philosophy on the project relating to failure and trapping. Essentially it states that if you display any optimism that you will capture a fisher then you are certainly doomed to failure – you’ll capture nothing. If this goes on for much time at all then you inevitably develop a deep malaise that  can easily transition into despair. About the time that you feel your endeavors are completely pointless and futile is generally about the time that you begin catching fishers.

Male fisher about to enter Trap

This is a peculiar phenomenon that has been observed independently by multiple biologists. Scott Yaeger (our good friend and collaborator from the US Fish and Wildlife Service) initially made me aware of this concept several years back when he noted that he was having good success capturing foxes, but that once he believed he would catch foxes he was unable to ever catch another. Another day while Richard Callas (again friend and collaborator from Cal Fish and Game) and I were trying to catch fisher for the 1st year of the translocation effort, without success, he commented that he has also made similar observations relating the optimism of the researcher to the likelihood of success. In fact, it was during his description that he initially mentioned that we would need to sink into the “Depths of Despair” before we might have any success. Moreover, as Richard noted, the despair must be genuine. If you invoke the depths of despair with secret belief that it will bring success then you will always be disappointed. This is why you always capture animals on the last trap of a long line that produced no other animals, or on the very first trap that you feel was placed in poor habitat and could never catch an animal.

Shelly with sedated male fisher

No work as been done on how many, or if all, the biologists contributing to a project must be in the depths. Perhaps it is neccessary for only 1 truly caring individual to fall into this strange abyss of perceived failure? Maybe more importantly no one has established a statistical link between disposition and captures success, and it stands to reason that no one ever shall. In any case, tonight we sit. Perhaps not quite to the point of despair, but certainly with little hope that our traps, which did so poorly the last few days, will redeem themselves or us.  I include some photos from a happier time when traps were full of fishers and our moods more salubrious.

Fisher in Trap

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Hangin’ with the Beard

Yesterday saw Roger and I back in the field tracking female fishers near the Ishi Wilderness Area. The Ishi Wilderness area is a unique place near the northern end of our study area and lies just to the west of the Stirling District. Located along Mill and Deer creeks the Ishi wilderness is relatively low and dominated by Grey Pine (Pinus sabiniana) and other vegetation associated with the foothills.

View of Blackrock near the Ishi Wilderness

The Ishi Monument located near the Narrows

Our fishers were not quite into the Ishi wilderness but they were quite close. We found one female in Deer Creek just below (to the North of) Sugarloaf. It took us a few tries to get a reasonable location (triangulation) on her, but in the end we felt pretty confident in our estimation. The other female was just over the ridge near the Narrows in a small tributary of Mill Creek. Both females could be heard from the Ishi monument located in this area (see picture). This girl was a little harder to narrow down because her signal was bouncing all over the place. This is pretty common but is made worse by the rock faces and pinnacles that are found in this area.

Sign Post for the Narrows

Eventually, we did a reasonable job locating two females in a pretty cool area. Roger and I had some good discussion including the possibility that I may be suffering a psychological condition associated with getting a PhD. This seems pretty obvious since only a person with mental problem would get a Phd while working on fishers.


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Return to the field

We seem to be having a spell of good weather over the district currently which is allowing a little more freedom in the field since our return from the West Coast Fisher Symposium in Sacramento. There is still a little snow on the roads at higher elevations and the peaks of Lassen to the North are finally showing white but skies are clear and most of our access points are open.

Yesterday saw an overdue visit to some of our more Northerly females on the edge of the Ishi Wilderness, we currently know of two females in this area, both of whom were located yesterday.

Today I managed the first walk-in on our most recently collared female (see post January 25th 2012). I found her in a draw high above Big Chico Creek keeping an eye on me from the canopy of a large Douglas Fir. The photo fails to do her justice but you can make her out peering down from a mass of branches some 100 feet from the ground.

This being the first time we’ve had contact with her since she was collared I was pleased to note that she didn’t appear agitated, neither vocalizing nor attempting to move off while I was observing her.


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Pekania pennanti

The recent meeting of the Western Section of the Wildlife Society has been interesting. One important conclusion that Roger and I have reached is that it really is time to start calling fishers by the genus Pekania based on work done by research from Koepfli et al 2008. The alternative would be to put wolverines into the genus “Martes”, but such transitions seem unlikey.

Sure, if you still call them Martes pennanti we’ll still know what you are talking about, but this way is more fun (and accurate). Okay, I”m not sure I’m willing to completely give up on fishers being a “Martes” species, but the genetic work is interesting and something we should give serious consideration to.


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Springing the trap

Though the aim of our trapping efforts is to catch fishers, we sometimes find non-target species in the traps.  Striped and spotted skunks, ringtails, grey fox, and squirrels are the usual suspects.  Some of them even seem to find the wooden cubby of the trap comfortable!  Last time I caught a ringtail, I opened the back door of the trap and left to do other work.  Upon returning 4 hours later, it was still resting in the box!


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