Posts Tagged With: sierra

In Search of a Den

The other day I found myself standing on a fallen log, trying to decide which way to go next.  The occasion?  I was attempting to walk-in on female 21FB6 in hopes of finding another one of her maternal dens.  I knew that I was close.  I had just passed the “sigh of relief” point; that grand moment in a walk-in when you know that you are close enough that the fisher isn’t likely to run away, making the trudge through a few hundred yards of thick understory vegetation (and in this case, millions of spider webs at face level) worthwhile.  Especially at this time of year, dens become harder and harder to locate.  It seems that females only spend a short time there before heading off again to forage.  As such, I was excited to get close and find her resting.

There were a couple of likely den tree candidates next to where I was standing.  To one side of me stood a good sized maple, which looked like it might contain a few cavities.  On the other there was a very large Douglas fir, which was tall enough that I couldn’t see a large portion of it due to the understory vegetation.  When you get very close to a fisher, it is often difficult to determine exactly where it is.  The signal tends to change dramatically with every step you take, leading you off in various directions for a few meters before abruptly changing again.  The solution I usually use to find the animal is to back a little ways away from the suspect trees, and circle them from a distance.  More than not with using this strategy, one of the trees eventually stands out as the more likely candidate.

21FB6 down in a log.

21FB6 down in a log.

Standing between the two trees, I was getting my strongest signal yet, but the signal kept changing.  One second, I would think she was in the maple.  The next, the signal from the Douglas fir was stronger.  I took a few steps away from the log and listened again.  To my surprise, this time the strongest signal didn’t seem to be emitting from either of the suspect trees, but from the log I had just been standing on!  I moved to one end which was hollow, and shone my flashlight in.  Two bright green orbs were reflecting back.  I had literally been standing directly on top of her!

This was only the second time that I have found a fisher resting in a fallen log, although I suspect it’s more common than we document.  I don’t believe she had any kits with her, but it was difficult to get a good look because she was far back in the log.  It is fairly rare (for me at least) to walk-in on a denning female who isn’t in her den, so I was a bit surprised to find her where I did.  Although I wasn’t able to find a den in this case, it was certainly nice to get a look at her!

Log 21FB6 was resting in

Log 21FB6 was resting in.

View of another female resting in a log from few months ago.

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“Fire Ferocious”

“Fire! Fire! Ferocious fire! 
You restless wall of flame. 
Fire! Fire! Roaring higher! 
Your fury to never tame.”

                                     – Mark R. Slaughter


Fire is an omnipresent threat to both individuals and populations of fishers. Fires that burn very hot can devastate the over story trees and with them the places where fishers forage, rest, and den. So, we are always aware of the potential effect that a large fire might have on our relatively small population of reintroduced fishers.

In the last week a fire just to the east of our study site (the Chips fire) has been putting up a lot of smoke and growing ever larger. Presently, the fire doesn’t directly threaten any of the fishers we are tracking, but its western boundary is within 5 miles of at least 2 females. Since the fire began on July 29th it has grown to nearly 16,000 acres and is not predicted to be contained for at least another 2 weeks (see the link already provided).

If you examine the included map you can compare the current area of the fire to the area where the majority of our female fishers have been found (blue dots; these data are incomplete and unedited) and where they have denned (black crosses). Though I have not delineated individual females in this figure you can see that a fire of similar area positioned in the middle of the study site would encompass a large number of dens and female home ranges.  Additionally, when you consider the fire shown here is relatively small (the largest wildfire can be over 100,000 acres) you can begin to appreciate how easily a single fire event could have dire ramifications for any fisher population in the west (in particular reintroductions).

Hopefully, the Chips fire will have little (preferably no) effect on our reintroduced fishers, but as with most things, we just don’t know what will happen. Fishers are obviously not the only species that are threatened by fires (marten are found in or near this fire), but they are our primary focus in this forum. Eventually, fire will likely have some impact on this incipient population. Those impacts will be related to the population size and spatial distribution of the animals. With luck, the population will grow and expand so that it can withstand perturbations such as wild fires.

Map comparing the area of the Chips Fire to female fisher locations


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The Great Kit Debate

In a somewhat desperate bid to up my posting rate I’m going to revisit old ground in this post and return to a brief email debate from last April.

And so a brief background is in order…

As we build up to this years denning season we have begun the task of collating and analyzing our camera data from the first two denning seasons on Stirling. As many of you may know the season really begins to heat up in early April as we confirm natal dens (a natal den is the den in which a female gives birth to her kits) by performing walk-ins on stationary females. It is usually on the second walk-in to a given tree that we consider the female has indeed denned. At this point we set a series of remote cameras around the den structure in order to passively monitor the females activities. Through the denning season a female Fisher will usually progress from her natal den through a number of maternal dens (a maternal den being any den occupied after the natal den). Thus one of the most exciting things we see on our cameras is the female carrying her kits out of the den, this gives us a great opportunity to count the number of kits.

So here the debate arises. While going through our pictures of female 17582’s natal den from the 2011 season I came across some familiar images, the first image is of 17582 moving her first kit from the natal den to her first maternal den roughly 100 yards away. Nothing too contentious there.

The picture below was taken 20 minutes later and appears to show her moving a second kit, or potentially a second and third kit at the same time, as the wily Roger Powell contended.

And here is the same image expanded;

So I ask your opinion,


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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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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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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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Creatures of the night

With the belated and thus far underwhelming winter storms making an appearance recently a few of us have found ourselves with time on our hands away from the field. In light of this situation the ever industrious Aaron has, among other assignments, set us to work organizing a digitalized mountain of trail camera pictures.

As a (more?) naïve youth I used to quite enjoy going through these pictures, then I came to work in bear country…needless to say, the novelty has worn a little thin. For the uninitiated; it is a favorite pastime of black bears to find, wander around in front of and then try to eat trail cameras, this can become a little tedious to watch the 10th or 100th time you see it. Nonetheless, we do get to see some of the more reclusive local residents going about their business too.

I thought I’d share a few recent favorites to add a little color…then I realized they were all night shots.



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New juvenile fisher

Today we captured a new juvenile fisher near Hwy 32! This is the 5th juvenile female fisher captured this year (2011-2012), and the 9th total juvenile. She was collared with a VHF transmitter and we will begin tracking her as much as possible in the near future. This is exciting news because thus far 6 fishers have been documented to have died on our project. Capturing 9 juveniles that are independent of their mother’s and surviving indicates that at the least we have replaced those deaths with fishers born on the study site. This is one indication that the populations may be stable or even growing.

Currently we are tracking 24 animals with VHF transmitters and another 9 with Argos satellite (PTT) transmitters. Capturing, collaring and following many animals is important to improve our understanding of what habitat requirements they have and how that is influencing our incipient population.


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Winter wonder land

The first major winter storm we’ve had since November is upon us. So far we’ve gotten a few inches of snow at the lower elevations of the study site, but maybe quite a bit more up high. This makes the roads and conditions difficult and so not many telemetry points being taken right now. it does allow us to work on data entry and analysis a bit more, and with the upcoming meeting of the The Wildlife Society it is not a bad thing. A positive aspect is that we can do some snow tracking of fishers when the weather is bit nicer. It is always fun to follow fishers for a while.


It can get deep quickly

FIsher tracks in the snow

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40 fishers have been released

-Dec 23 2011-

After three years of much discussion, thinking and hard work  we have finally finished moving our target number of fishers (24 females and 16 males).  We have taken fishers from many places in Northern California on publicly and privately managed lands. Fishers have been released in Deer Creek, Butte Creek and and the West Branch of the Feather River. These represent 3 distinct and important watersheds that occur on the Stirling district. Our goal in releasing fishers in these diverse and widely distributed areas are to place fishers throughout much of the district, allow them access to varied land cover types, and to avoid placing them in the established home ranges of animals that have already been released (this was primarily a concern in years 2 and 3). Fishers often do not stay in the areas we released them in, but to a large degree they have settled over a large portion of the Stirling district. After 2 years of study we know fishers occur in all the major water sheds located on the Stirling district and in lots of diverse areas and elevations (ranging from 2000 to 6000 feet).

A lot of people and groups have made this happen and it has been an interesting and fun group to work with. It is clear that we could not have gone as far as we have without all those contributions.

Now that the work of moving animals to Stirling is over we will concentrate our efforts on the animals that have been moved and their offspring. In addition, we still have lots to learn about what areas they prefer and how this affects the success of the reintroduction and what that information tells us about what fishers need. It promises to be a lot of fun!


Roger waiting for male F605B to leave the box

Kevin releasing male 18AA5 (fisher is on left side of picture)

Aaron letting a fisher go

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