It would, indeed. This year, in my area, we are having an abundance of snow, but in the forest, it's not terrible, yet. And there is a good crust, so fisher may not suffer.
Time will tell, as they are new to this area, as historical presence goes.

I would think that might be the case too. The heavier critter might not do as well in deeper snow.


Viking. The three that you have caught within a mile of each other....all being females, leads me to wonder if they are similar to wolverines ??? Maybe female juvies set up shop in the same home range as mom for a year or two ?
I'll see if I can rouse Gulo

That would make sense to me.

I'll throw my 2-cents worth into the discussion, but it may only be worth a penny.

Up front, I will say I've not worked extensive field studies on fisher. My notes herein are based on various literature readings over the years, some laboratory work I've done on fisher carcasses, and a bit of head-scratching I've done in northern Idaho at the apparent proliferation of fisher over the past 4 decades and the concurrent apparent decline of marten.

It is very interesting to me that your harvest over 3 years has been females. I would have guessed just the opposite, as the males generally disperse greater distances than the juvenile females, thus have a greater chance of encountering traps. I'm further assuming that the captures have been yoy or yearlings, not adults. However, a sample size of four is good anecdata, but certainly not definitive. I'm astounded that ADF&G does not have a carcass buying program to try to document the harvest statistics a bit more precisely thus perhaps actually manage the resource sometime in the future.

You mentioned, viking, that one of your carcasses had blastocysts (obviously, not a yoy). The blastocysts are actually 8-cell stage pre-implanted embryos and can be used to give an indication of the number of young that potentially will be produced in the upcoming whelping season. The corpora lutea/corpora albicans, if they are persistent, can be used to count number of kits whelped in past years. At least in marten, the c.l.s or c.a.s are not persistent; I would assume the same in fisher.

My understanding is that in places where fisher and marten are sympatric, generally the fisher has seemed to be the winner at the expense of marten (California Sierras, Vermont, New Hampshire, Maine, Ontario, Quebec). In the long-term California study, the marten seemed to do better in the higher elevations (lighter density deeper snow) while the fisher did better in lower elevations (often rain-crusted snow). This is assumed to be due to differences in foot-loading between the two species (that is, the fisher sinks in light snow while the marten effectively "floats"). Also, dense shrub areas were apparently refugia for marten. Other studies has suggested that mixed forests (higher proportion of deciduous trees) are conducive to fisher population expansion, whereas the marten seem to prefer more pure evergreens. There are numerous documented cases of fisher preying on marten. Also, it has been postulated that dense or crusty snow conditions favor fisher for yet another reason. That is, predation by other mammalian and avian mesocarnivores probably does take a toll on marten if they are unable to use the subnivean, while the larger body size of fisher enables them to fight off some predation attempts (by great-horned owls, foxes, etc.). In my own observations, marten are largely specialists on voles. Sure, they take a variety of prey (including berries) but don't have the ability to take the variety that is found in fisher diets. As an aside, I was amazed in looking at stomach contents of fisher in north Idaho (only a sample of 25 carcasses) that even things like garter snakes were consumed (where are they getting garter snakes in November-February?).

If I've missed the primary questions, let me know, and I'll try to opine a bit more.

BTW, Merry Christmas to one and all!

Jack

Thanks, Jack. Always appreciated.
I should add that I know of 2 other fisher taken in somewhat close proximity to the last 3 I harvested, and in the same time-frame. One male, and one female. I do not know age class.
And I have not seen any fisher tracks or scat in these areas, at all. They just appear. On the other hand........

Doing my flea work has always showed some interesting aspects of fisher past food sources. They do carry the normal microtone flea species found but what is interesting is always a large sample of a flea only found on wood chucks ( skunks as well) which are always associated with the dens. Around here skunks co-exist in winter dens of chucks. We have had total collapsed of snowshoe hare population and they still survive. Consider a 6 pound steak in a rock pile food for thought. That would explain garter snakes in their diet being under ground..
One trapper that I know took 12 female fishers at one location one season, but he knew it was a hollow tree, and probably a denning/ nursery
my two Canadian cents worth= by the way they no longer exist here

this is from Hollands Fleas of Canada and Alaska published 1985 after his untimely death it was put together.
Few of the dots are mine but I have put a few more on the map since then.
It would be interesting to see some of the Hoary marmot range on there as well.

I'm no fisher expert, but I will say this, every place you find marten in Northern Idaho, you will find fisher. Even in places where Fish and Game say there are no fisher, I have found fisher tracks. In fact one of the places where Fish and Game claim there to be no resident fisher is where I would say is probably the second highest population of them I am aware of. My dad has caught several there in the last couple years incidental in marten traps, including releasing a big buck from a 120 alive a couple weeks ago who must have gotten caught just as he pulled up. (he said that was rather exciting). Either Fish and Game don't know what fisher tracks look like, or they don't want to admit to the population we have. They are talking about giving us a limited season, however. Which is good, because in my experience you can find fisher in quite a few places where there aren't marten, but I've yet to find marten in a place that doesn't have at least the occasional fisher. They do seem to live in the lower elevations with less winter snowpack than marten, but they also like the high elevations and deep, soft, snow where there is very little else. I've seen fisher spend considerable time at alpine level, crossing and using through open areas above timberline, not only higher than marten, but higher than practically anything else, including food sources.

But at those high elevations are the Hoary marmots and pikas up there ? Therefore their food source
if you have ever seen a fisher squeeze through a small hole into a chicken coop you would know what I mean

This last fisher had a few fleas, as do most of the marten I catch..

No, but we do have tons of ground squirrels up there in the summer. Which I'm assuming fisher can dig down to their dens in the winter.

Marmot are common right down to sea level in SEAK.

Do you guys up around Juneau suppose they are coming down the Taku drainage? Any patterns to where they are being caught that would suggest anything?

I have no doubt the "originals" came down Taku. I have a friend that lives year-round up there, near the border. He trapped that country for a couple decades, and would see fisher off and on. They became more frequent the last 20 years, or so. He doesn't trap anymore, but drives a supply barge up and down the river from the border to town as long as there is open water, to this day.
I don't think for a minute the ones we catch go on a lark from B.C., and find my sets. They are getting established, slowly, but surely.
As fisher habitat goes, they may well do ok here. I don't think they will thrive, but certain pockets might be just their ticket.

Maybe Catcatcher from Atlins BC will chime in, of some of the fisher movements in his region.

There is one thing for sure , that my flatlander legs are not going to spring through those alpine meadows as they did 50 years ago.
Alaska viking you can pm me about some flea collecting and methods for the museums collection

Yeah I caught the first fisher 5 years ago and one more the next year both were small females, both within a mile along the silver salmon river which dumps into nakina and then into the Taku. I have eased up on the trapping the last couple years, my marten died off so I’m hoping this year there will be a few more.

My marten pop has decreased. as well, though I think it is very localized. The nearest other line is holding constant.