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Timing is important

I thought I would share a link to our recently published paper in the journal Ecosphere. See the paper at this link.  In this paper we collaborated with the good folks of the Olympic Peninsula  fisher reintroduction to demonstrate that when we release a female is important toward her short term reproductive success.

In addition to showing some interesting biology on fishers I think the paper shows the power of collaborative efforts between projects. Thanks to all the folks from Washington for all their help and support on this paper as well as to Roger and Richard for their help in writing it.

ANF

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Hair-raising adventures

Over the past six months I have cleaned and analyzed over 400 samples of fisher scat that had been collected during trapping events, den trees and walkins from 2009 to 2013. While being a scat analyst has not been the most glamorous job, I found the work to be extremely interesting as well as informative.  I completed this work in the Biodiversity Lab at the North Carolina Museum of Natural Science’s Nature Research Center (special thanks to Roland Kays).  Before I was able to start going through the samples, I had to create a reference collection of animals that were likely a part of a fisher’s diet potential prey animals (like porcupines – see picture).

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Porcupines – making people happy

This gave me the opportunity to explore the full collection of mammals at the museum and take hair samples from those species. With these samples I made slides that demonstrated the cuticle and medulla for each species.

This allowed me to compare hairs found within the scat samples to hairs from known samples of identified animals.  In order to identify what the fishers had eaten, I first had to clean the samples.  The washing machine in the lab was not able to sufficient to separate and clean the samples so I had to clean each one manually.  The rest of the lab was not very fond of cleaning days; as you can imagine opening and handling scat that had been frozen for a year or longer does not smell like flowers.  I had two metal wash drums with different sized grates and a soft fine mesh lining in a sink with a tube attached to the faucet.  For each sample I would place 90% of the scat onto the first drum and leave the remaining in the bag to be used for hormone analysis.   From there I would run water over the sample to filter it through the grates and clean all the feces off of it.

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Washing samples

Remaining particles that couldn’t pass through the drum would be moved onto a plate and I would repeat the process on the second drum and then again on the fine mesh.  Once a sample had been completely cleaned and all the remaining particles were separated onto a labeled plate it was put into a dryer. After about a day the samples would be dry and the analysis began.  Hair identification can be a grueling but fun process. Species within the same family, for example squirrels (Sciuridae), all have very similar medulla and cuticle patterns. Therefore, it is important to be able to identify the small differences.  For instance, normal guard hairs for the western Gray Squirrel (Sciurus griseus) are black with a single white band near the center of the shaft with significant kinks throughout, whereas the hair for the California ground squirrel (Spermophilus beechyi) is black with a single white band slightly closer to the tip and less kinks.  If I was not able to identify a hair by using a dissecting microscope I would create a slide with the unknown hair and place it under the compound microscope to see and compare the cuticle scale pattern and medulla pattern within the hair. Along with hair identification I was able to determine a prey species by remnants of tooth and bone as well as scales, feathers, or exoskeleton.  Most often I found evidence of various species of rodents (especially squirrels), but there were other interesting things fishers ate. For example, one fisher in particular had consumed common wasps (Vespula vulgaris) on multiple occasions.  These samples were very intriguing since the wasps were still in tact.

he data I compiled will be used to continue learning more about the diet of fishers and hopefully identify habitats with available prey.

~Kyra Pruitt currently attends NCSU and serves as one of the many excellent technicians doing great work on the fisher translocation project.

 

 

 

 

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A better mouse trapper

Fishers, like most mustelids, are predators. Unfortunately, the food available to them versus what they kill and eat are often unknown to researchers. We have dedicated a good chunk of our summer trying to understand better what is available for fishers to eat compared with what they actually select on our study site. This summer we had several folks out trapping and documenting potential prey species for fishers across the Stirling district. Many people were involved but we had three excellent field crew out there doing most of the work. Alex, Erika, and Jesse (see their lovely photos below) were out most days setting and checking traps in diverse types of cover and tree stand types. The point of all this is to attempt to understand where specific types of prey are found on the landscape based on differences in the environment and forest management practices.

We are just starting to examine these data to document and explore specific patterns of occupancy and distribution for different prey species. Nevertheless, we encountered many different species of mammals, birds, and herpetofauna (snakes and lizards mostly) across the landscape thru the summer. We captured deer mice (Peromyscus spp.) just about anywhere we set traps, and woodrats (Neotoma spp) also occupy diverse land covers types. We do not catch them as often as deer mice, but they are still abundant. The crew also captured ground squirrels (Otospermophilus beechyii), Douglas squirrels (Tamiasciurus douglasii), various chipmunks, and even hapless ringtail (Bassariscus astutus). While setting and checking traps they also kept an eye out for lizards and snakes. A few of the snakes were of the venomous variety (rattlesnakes) as well as snakes that are not quite so dangerous but just as cool. Alligator lizards and fence lizards also seem to be in lots of places as well. Other types of potential prey species like gray squirrels, black-tailed jack rabbits and flying squirrels were also noted but seem to be harder to capture in live-traps.

Of course, when you put a lot of fresh peanut butter and oats out in a forest you get other critters that are interested. Bears are a common visitor and they are usually unconcerned with maintaining the integrity of our trapping grids. They move, turnover, often destroy, and at other times even steal traps! Bears are one of our nemeses both when doing this kind of work and just about everything else (they are everywhere). We also see foxes and occasionally we even see a fisher wander across a trapping grid.

The crew is primarily taking data on where we capture specific types of animals. They also document the sex and relative age of each species, measure the weight, examine them for ectoparasites and  give them marks and tags so we can document which individuals we have recaptured. We are also collaborating with Deana Clifford and the Wildlife Investigations Lab to evaluate some captured animals for rodenticides and diseases. All these data are important to future analyses and monitoring.

Vegetation types are also important and we

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collect information on the number of trees and shrubs that occur on each trapping grid. Sometimes the crew accidently document other species of plants. They often don’t’ know this until a day or two later when they realize they have a poison oak rash and then must bear the burden of scratching and itching for several days. It’s a badge of honor. We all wear it proudly at one point or another – except for those people lucky enough not to be affected (we are all looking at you Jesse) – if not without a large degree of annoyance.

Good times were had by all and more importantly we have collected new and interesting information that will help us conserve and manage fishers and fisher forests.

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On this day

Today (December 9th) is a special day for me. Five years ago today I recall walking down a snow covered mountain road holding one end of a wooden box that contained a fisher. Holding the other end of that box was Roger and right beside us walked Richard and Scott – also holding the ends of a box the held a fisher. Our destination was a small clearing in the forest where many of our friends, colleagues, and even members of the media awaited us. More precisely, they waited for the fishers. The two female fishers we carried in those boxes would be the first 2 fishers released as part of our translocation project onto the Stirling district. We placed the boxes near the edge of the clearing and opened the doors and waited, and then we waited a little more. All the humans eagerly waited for the fishers to emerge from those boxes, but the fishers had other ideas. I can’t say I blame them. Having a bunch of beady-eyed humans looking at you can’t be a fun situation for a fisher (or any other creature either I imagine). I suspect we all, especially the members of the media, had a great illusion that the fishers would emerge promptly and slowly, pose for a few pictures, and then saunter away at a leisurely pace while we snapped pictures and looked on in awe. The reality was quite the opposite as both fishers, in their turn, streaked out of their boxes as a flash of brown into this new place they we hoped they could make into a home. Seeing the fishers run off gave a sense of great accomplishment and wonder but also of great responsibility and future hard work. I suppose Scott provided the most sobering perspective of the day (to me anyway) when he simply said “There are now fishers in the northern Sierra”. Yep, there sure were and that meant that we had to keep track of them, study them and also move an additional 38 fishers over the next 2 years.

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Releasing a male fisher in December 2009

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Female fisher looking out of release box

Two years later on December 9th I was once again standing in a big circle of people waiting for fishers to come out of wooden boxes. Once again the media (see link for one article and some pictures) was there as well as friends and collaborators of the project. The outcome was much the same as fishers sat in the boxes refusing to leave and when they finally did they fled with extreme expediency. We released 2 females and 1 male, and they would be the last of the fishers translocated to Stirling. Not all the releases were met with media attention or lots of people milling around waiting to take pictures. In fact, most fishers were released with just 1 or 2 people looking on and waiting. Personally, I prefer a small release entourage. In all cases, the releases were the easiest part of the whole process.

It might take me an entire book to write about the tremendous effort that it took to get fishers to Stirling. There are myriad stories about trapping, handling, and transporting fishers. There are just as many about long meetings and phone calls where we considered all the risks and benefits and tried to decide the best course of action, and for each story I have the rest of our team might have 20 more. Yet, all those stories and experiences would only tell a small part of the entire story, because there were literally years of planning and discussion that went into developing and creating the project and the collaborations that made it all work. Most of that happening long before I ever even knew about the project. So, while I consider December 9th the birthday of the project we should always remember that it had a very long gestation as well, and that process went without fanfare or appreciation. The days we released fishers, and how those days came to be, are only one part, and perhaps the least important part, of what our project is all about.

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Some of the team handling a fisher before release

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Transport boxes full of fishers heading to Stirling

On December 10th, 2009, a day after we released the first fishers, Roger and I set out to find them. It was a mixed bag as we found one female within 1 km of the release point and had no luck finding the other. It took a few days, a few weeks actually, but we eventually found the other female. We tracked both of these females, as well as 7 other released in late December and January of 2010, throughout the spring. Both those two females survived and produced kits the first year as did most of the other females we tracked. Since that day we have spent nearly every day for 5 years looking for fishers to understand the specifics of how and where they live and reproduce. Of course, “we” isn’t Roger and I anymore. “We” is now a large number of folks that work, and have worked, in the field collecting data, and without them the project would not continue. It is also all the people behind the scenes and behind desks and telephones, in front of computers, in laboratories, and in many places and roles that make the project continue to work. The project would have failed a long time ago without all those many people and they all deserve a great deal of gratitude and appreciation. We continue looking for fishers and learning about their lives and ability to survive and reproduce on a landscape managed primarily for timber production. We don’t know everything, obviously, and though we’ve made great strides more information, time, and thinking is needed to fully understand the dynamics that drive fisher populations on Stirling. Nevertheless, five years later we know that there are STILL fishers in the northern Sierra Nevada.

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Getting the Point

Getting the Point            

October is long gone and the shortening days of November signal that fall trapping is coming to a close. Unfortunately, we have not been able to update all of you with the happenings as much as we’d like, but I suspect we’ll be putting out more posts in the coming weeks.

One of the parts of trapping, and handling fishers, that I most anticipate is in the moments after we’ve sedated a fisher and get to physically examine it for the first time. One of the first priorities is to  see if it has any major wounds or ailments that need immediate attention or that give us concern. Recently, while examining a female fisher (captured on Stirling in the fall of 2012) we noticed that there was something odd about the area around her right shoulder and neck. Not coincidentally Roger and Kevin both spotted the same thing when I did and all three of us were looking on at several very large, stiff, and prominent hairs jutting from the fisher. I found myself thinking ‘those don’t look like fisher hairs, and I wonder what they are?”. Kevin and Roger were apparently thinking the same thing and nearly in unison we shouted “PORCUPINE!”. A little further examination confirmed our suspicions. Three porcupine quills were embedded in the young female’s right shoulder suggesting she had an encounter with porcupine in the not too distant past.

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Close up of 3 porcupine quills in right shoulder of female fisher captured on Stirling in 2014

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Female fisher with porcupine quills in right shoulder

Perhaps you are wondering why such a fuss about a few porcupines quills? Well, there are a few reasons that this got us excited, but mainly it was because we have never found a fisher on Stirling with porcupine quills. The discovery is significant because fishers are one of the few consistent predators on the spike-laden rodents when they occur together. As  you probably know, or can deduce, porcupines have all those spikes as more than just a bold fashion statement – they offer pretty good protection from most predators (view a recent video of an African porcupine vs lions). Fishers are uniquely adapted to capture and kill porcupines and they may have an important role in regulating porcupine populations in some areas. Porcupines are large relative to other prey fishers catch and kill (e.g., squirrels and hares) and they provide a large source of energy to fishers (read this if you want to learn more). We have never documented porcupines on Stirling, since we’ve released fishers, and this suggests that porcupines are rare. Having porcupines and fishers on Stirling at the same time might alter the dynamics of how and where fishers forage, their home ranges size and structure, and even their population dynamics.

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Porcupine (Erethizon dorsatum)

We don’t know if our female fisher actually killed a porcupine, but she certainly ran across one and we have a pretty good idea of the places she likes to hang out in. For now, it is only a fun little anecdote about one of the fishers on Stirling. Nevertheless, it is an exciting story and perhaps the first in a series of important observations. Such information is one of the reasons we endure a long trapping season and why we subject animals to the burden and stress of capture. Ultimately, it is all important information about what fishers are doing and how their daily lives translate into their ability to persist.

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Depiction of a fisher capturing a porcupine (painted by Consie Powell)

-ANF

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“What’s past is prologue”

For those of you not aware, our annual fall trapping effort on Stirling has been underway for several weeks now and we are getting lots of exciting results. Probably the most exciting, at least for me, is that we recently captured a female (ID: F8B8D) that we released in year 1 (2009-2010) of the project. Capturing this important for a number of reasons and I’ll explain those reasons a bit better a little further along. First, I wanted to give a little history on this female to give some context for why her recent capture in important.

Fisher F8B8D in the fall of 2013 (top) and the in january of 2010 (bottom). We photograph the undersides of all fishers to describe and identify their unique patterns of markings. If you look closely you can tell this is the same fisher by examining her pattern of white blazes.

Fisher F8B8D in the fall of 2013 (top) and the in january of 2010 (bottom). We photograph the undersides of all fishers to describe and identify their unique patterns of markings. If you look closely you can tell this is the same fisher by examining her pattern of white blazes.

Female F8B8D was captured in January of 2010 north of highway 299 and between Shasta and Trinity lakes. We deemed her a good candidate for translocation to Stirling because she appeared to have reproduced in the past and she was in good physical condition suggesting she was mature and good handle the stresses of being hauled off to a new landscape. Like all females in the first year of the translocation she was implanted with a VHF transmitter so that we could track her movements. After she cleared our disease protocols we translocated her to Stirling on January 10th and released her in a tributary of Butte Creek near where most of our year-1 fishers were released. I can tell you she didn’t stay there for very long and the next day I found her on the east side of the ridge in the West Branch of the Feather River. For the next 6 months we often found her on the ridge between these two drainages (see the map of her 2010 home range). Unfortunately, we could never confirm that she had kits, because she never stayed in a den tree for very long. We suspect this may have something to do with the timing of when she was released, but that is another story. In the middle part of the summer F8B8D started moving south towards Stirling city and in fact the final time we found her signal in 2010 she was just to the east of Stirling city. Unfortunately, we were never able to find her signal again and all indications were that the transmitter had failed in early August of 2010.

on the left is veterinarian extraordinaire Diana Clifford, along with ANF, examining fisher F8B8D prior to surgery to surgically implant a VHF transmitter on the right.

on the left is veterinarian extraordinaire Diana Clifford, along with ANF, examining fisher F8B8D prior to surgery to surgically implant a VHF transmitter on the right.

 

 

 

Estimated home range (black lines) of female F8B8D in 2010 as well as the location of her original release site (red star), last known location in 2010 (blue circle) and both recapture locations in the fall of 2013 (red circles). The green line is the access road used for setting and retrieving those traps.

Estimated home range (black lines) of female F8B8D in 2010 as well as the location of her original release site (red star), last known location in 2010 (blue circle) and both recapture locations in the fall of 2013 (red circles). The green line is the access road used for setting and retrieving those traps.

Since we lost track of F8B8D in 2010 I’ve often wondered about what became of her. Each time we’ve trapped she has been a female that I’ve specifically thought about and tried to places traps in her former home range and in places I thought she might have settled into. We never had any success catching her and frankly we’ve had very poor success trapping any female that we released in that first year. In fact, up until this fall we had only recaptured 1 other female from the year-1 cohort and that was back in the spring of 2011. In truth, I had resigned myself to the idea that those females were all dead or were just of the disposition to never be captured again. Of course, not knowing which of those two possibilities were true was a problem because we it left us without important information.

The recapture of F8B8D helps to answer a few of those questions. Or, at the least it gives us insight into what the truth really is. Most importantly, we know that some (at least one) females that were released in year 1 are still alive. Maybe there are more out there living in places that we released them and hopefully giving birth to new fishers that will help to maintain our young population. Now that F8B8D has been recaptured (twice now actually) and collared we can see what her current home range looks like and how it compares to the areas she was using in 2010. We can also see how other fishers have been responding to her current home range by studying their space-use in relationship to hers even while she went untracked. F8B8D was recaptured not too far from the last place we tracked her and so perhaps she has been living in that same area this entire time. We also learned that the implants that we gave these females can remain in them and have relatively little impact on them. Upon removal the transmitter was still intact and doesn’t appear to have done any internal damage. F8B8D was about the same body mass and condition as when we released her and that suggests that she has been making a reasonable living for herself since we released her. Based on her teat size we also think that F8B8D likely had kits in the past year and this demonstrates that the year-1 females are not only living but also reproducing. Now, it’s possible that this is the only year-1 female still alive, and we just don’t’ know for sure, but it is a positive sign.

The underside of Fisher F8B8D showing large teats, indicative of a female that gave birth in the past year. Note that her belly has been shaved so that the implanted transmitter can be surgically removed.

The underside of Fisher F8B8D showing large teats, indicative of a female that gave birth in the past year. Note that her belly has been shaved so that the implanted transmitter can be surgically removed.

 

 

 

 

Fisher F8B8D in a transportation box after surgery to remove her implant. She was also fit with a new collar, re-vaccinated for rabies and canine distemper, and her general condition assessed. Fishers can be released back into the wild  within a few hours after surgery without any obvious impacts to their well being or behavior.

Fisher F8B8D in a transportation box after surgery to remove her implant. She was also fit with a new collar, re-vaccinated for rabies and canine distemper, and her general condition assessed. Fishers can be released back into the wild within a few hours after surgery without any obvious impacts to their well being or long-term behavior.

 

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Kit Update

Over the past few weeks, we have been getting more and more photos of females moving kits to new dens!

To date, we have seen a total of 17 kits from 9 individuals (8 of these had two kits, and 1 had only one kit).  When the last update went up, we had seen kits from 5 of the female fishers we are tracking.  Of the remaining 4 denning females, 3 were native born fishers (accounting for 5 kits total), and 1 was a translocated animal (accounting for 2 kits).

It’s enjoyable to me to see the growth of the kits over time.  They sure do get big in a hurry, and it is somewhat comical to see mom trying to pick up and carry a kit that is nearly half her size!  With the last couple of dens that were found in June, we’ve seen that the kits are starting to become mobile, being able to move up and down the den tree on their own instead of carried around by mom.

Below is a slideshow of some of the kits we’ve seen since the last update.  It should run in chronological order, so you can get a feel for how fast these young fishers are growing.

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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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In The Field With Fishers

Our situation on the ground has been a little hectic over recent months and some of you avid followers may have been feeling a little neglected when it comes to field updates. Well, fear ye no more, I shall share a few details regarding the animals we are currently tracking on and around Stirling as of late February.

We are currently tracking 23 Fishers with active telemetry transmitters on and around the Stirling District. Of these, 16 are fitted with VHF transmitters that we must actively track. 15 of these animals are females wearing VHF collars, the other is a male born on Stirling in 2012 who was given an implanted transmitter due to his age and potential to outgrow a collar. The remaining 7 animals are males of greater than 1 year of age fitted with ARGOS collars, these collars collect locations via satellite and can be conveniently tracked from the comfort of our desks. A breakdown of these animals by year of birth/translocation can be seen in the table below.

Right now we are unable to account for 3 more animals (2 females, 1 male) with potentially active transmitters who we hope are still going about their business out there. They were all born on Stirling in 2012 and have been missing for over a month. Sometimes such animals turn up in unexpected places (see previous post “The Grass Is Always Greener”) or are recovered during our trapping efforts and sometimes we never learn their ultimate fates. Either way, they are young and wild and all we can do is to keep searching.

You can get an idea of the spread of our animals across the study area at the moment from the aerial photos below, to give a little perspective the lines on the image represent the county lines of Plumas to the East, Tehama to the west and Butte in the South.

Female locations:

Year 2 translocates in Yellow, Year 3 translocates in Blue, Juveniles from 2011 in Red, Juveniles from 2012 in Green

Year 2 translocates in Yellow, Year 3 translocates in Blue, Juveniles from 2011 in Red, Juveniles from 2012 in Green

Male locations:

Year 1 translocates in Purple, Year 2 translocates in Yellow, Year 3 translocates in Blue, Juveniles from 2011 in Red, Juveniles from 2012 in Green

Year 1 translocates in Purple, Year 2 translocates in Yellow, Year 3 translocates in Blue, Juveniles from 2011 in Red, Juveniles from 2012 in Green

As you can see we have a pretty wide spread of animals across our study area at the moment, and we are aware of uncollared individuals in many of the intervening areas. As denning season creeps up on us we will be kept busy trying to keep tabs on everyone, this year is shaping up to be an interesting one with more potential dens than any previous year, I will update you all with some of our denning predictions in the near future.

-CAB-

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The Grass Is Always Greener

One of the pleasant surprises during the fall trapping was recapturing an adult female, 1E003.  She wasn’t captured the previous fall, so it was the first chance we had to examine her since her release nearly two years ago.  Over the course of her time here, she has been a particularly challenging fisher to follow.  A brief history of this fishers’ time on the Stirling district:

During the spring of 2011, three months after being translocated, she denned and had kits over in the far eastern portion of our study area (at the time further east than any other females we were tracking).  This is a remote area of the district, and where she settled had fewer access roads than other areas.  We failed to capture her during the fall of 2011, but were able to catch a juvenile in her home range.  Through this past spring, we were still tracking her near her usual haunts on the eastern side of the district.  We found her in trees within 100m of each other on several days and believed she was about to den.  Then in mid-April, she vanished.  Her collars’ batteries were due to expire at any time, so we figured that was what had happened.  Thinking she had established a stable home range and would stay there, we weren’t expecting her to make any large movements.

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Area covered during 1E003’s move from the east to the west.

Much to our surprise, during a June 2012 flight, we heard her signal again!  This time however, she was on the complete other side of the district. Given the distance from where we normally heard this signal, we were skeptical that this was indeed our fisher.  Instead, we thought it might be the transmitter of some other species associated with a project unknown to us.  For much of June and July we continued to track and estimate the locations of the animal, but we could never confirm that it was a fisher by visually identifying it. Shortly thereafter, the collar disappeared from the airwaves again and we were left wondering if this was actually her or not.  As mentioned above, we captured her during the trapping effort in November, indicating that she had probably been living in this new area, on the west side, since June.  Sometime between April and June she made a 25km trek (as the crow flies) across the district and set up shop in a new area.

IE003 denning area near burn

IE003 denning area near burn

Naturally, we were left wondering why an animal would make a huge move such as this.  Immediately after being released, translocated fishers often roam around for a couple of months before they settle in an area. Often, juveniles and adult males make large movements as well, but this is more uncommon for an adult female.

This eastern side of the district is much rockier than other areas of the study area, and was hit by a large fire a few years ago.  I remember being surprised the first time I went out there to look for her den that a fisher would settle in this area (you can see in the map the differences in the sides of the district).  It is possible that the pressure of denning and giving birth made her pick and stick to a place that wasn’t ideal.  Since she was released in January, she only had a couple of months to find a good place to den. She may have not had ample time to find the best possible place, and simply chose the best in the area she happened to be in.

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1E003’s tracks from a few days ago.

The fact that she was able to survive, and likely raise kits, meant that she was getting enough food and other resources in the area.  However, it could be that with kits reaching adulthood there wasn’t enough to go around.  Possibly there was sufficient food, but maybe there was a paucity of mate choices (few males were known to frequent this area).  Fact is, we will probably never know exactly why she decided to pick up and leave an area she had occupied for over a year, or why she made such a long move instead of finding an area much closer.

Today, I was able to find her in a rest tree, about a mile from where she was re-trapped.  Since we captured her, we have been tracking her faithfully, and are starting to get a feel for the new areas she is using.  We know there are a few other female fishers right around her, so it will be interesting to see how she fits in.

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