Of the 45 fishers radiocollared, 14 are still being monitored (8F, 6M), 3 are missing, 10
shed their collars due to belting design failures, and 1 collar was removed at the time of
recapture due to neck abrasion. In addition, 3 juvenile males were ear-tagged only. Of the 14
known deaths (8F, 6M), 1 was struck by a vehicle, 1 was accidentally trapped out of season, 2
were legally trapped, 2 died from unknown but apparently natural causes, and 8 (6F, 2M) were
killed by other predators (scavenging by an eagle can’t be ruled out in 1 case).
Although sample size is small, all predation mortality of fishers took place from March –
May (Figure 3), and very rarely was any portion of a dead fisher consumed. Five of the 8
predation deaths, all females, were by mammalian predators. In one case, bobcat was
confirmed via trail camera placed at the site a fisher was cached. We are awaiting forensic
results for several other cases. Bald eagles are suspected in 2 of the 3 raptor predation events,
both of male fisher, though as noted above we can’t rule out scavenging in 1 case (only the
radiocollar was retrieved directly underneath an active eagle nest). The third raptor predation
involved a female fisher, likely attacked by an owl or hawk.
Of greatest significance, all 6 of the female fishers killed by other predators were adults,
and 5 of the 6 were killed while they still had dependent young in natal dens, indirectly resulting
in the death of their 14 kits. We suspect that energetic demands faced by adult females with
kits (i.e., lactation, and shortly after the energetically demanding winter) force them to increase
their activity in search of food, and preliminary data from temperature data loggers on
radiocollars suggests this to be the case. In addition, activity likely increases as a result of
breeding activity in the weeks following parturition, and all the increased activity occurs at a time
when concealment cover is diminished (i.e., before ‘green-up’), thereby exposing them to
increased predation risk. Regardless of the explanation, and acknowledging the limited sample
size, it seems unlikely that the high level of predation on nursing females is sustainable, which
may partially explain the recent decline in fisher abundance. However, the correlates to the
timing of predation mortality that we have mentioned are not new challenges for adult female
fisher, and the population appears to have been in decline only for the last ~ 6 years,
suggesting that other factors may be ‘altering the system’. It remains unclear whether the fisher
mortality pattern we have observed to date is consistent with past dynamics, and if not, whether
the underlying explanation is related to comparativel
y short- (e.g., periodic fluctuations in prey)
or long-term (e.g., deteriorating habitat quality) changes affecting fisher energetics/activity, or
relatively rapid changes in the predator community (e.g., the increased bobcat population)

Thanks Dirt. Great information.

Jack

Has anyone seen 1 lately?

Jim Woodford used to be in charge of the Wi Marten project, now retired. Dont know the biologist in charge of program who operates out of Rhinelander. I tried to get updated info on WI marten project from him but its like i never talked to him. So much for project manager. I was involved in the procuring marten from Mn to add new genes to Wis marten popluation. Some Michigan marten do cross over into Wi and breed with our marten. All the time and $$ that Ray Teske ( passed) and myself put into project and cant even get a update.

That's cool that you were involved. Thanks

This one watched me bait a bear bait. Forest co. October.. 23

My state has a marten re introduction program slated I am told. Not sure where it is at this point. I do know that with our hawk and owl population is quite high. And with them all protected I don't see a success is in store for the marten project just in that category alone. Most of our forested areas are broken up, have gas well roads, clearings, mined areas are reclaimed and established food plots etc.

Great browsing habitat for deer and elk but not much there for marten. I also can see coming some restrictions on trapping in some of the selected re introduction areas once that has started. There always comes a downside along with these funded projects. You will catch marten on the ground and in elevated trap positions so there is no stopping that.

In our big woods of the mature hardwood canopies will be open once the leaves fall and there are limited vast pine areas to give them good cover and protection. It is spotty at best. I have my doubts if they will flourish here and reproduce to become a sustainable population. I guess only time will tell.

We do have a good squirrel population and some rabbits and hares in some counties of the state, but our fisher population is growing leaps and bounds. We have a considerable population in and around where I live.

However, they are protected in our local zones. We also have a very good cat population, far more than many realize. They have certainly adapted and reproduced quite well. Many good trappers I know are catching 6 to 8 a season in a just a couple weeks that have to be released. I do that myself. We have a short season on them currently at one per season with a tag. Most of them are caught in canine sets as incidental catches.

Those of us old enough, remember when hawks and owls were managed like most other species. And there were fewer around. Now i can sit on my deck and see some kind of Avian predator with my binocs almost at will, whenever I look around. All kinds of hawks and eagles around here not many owls except in winter.

People here who still live off the land "manage"them.

This.
Marten need a lot more than trees and squirrels. Their needs are pretty specific, yet subtle and not necessarily easy to identify.
A big misconception is the need for squirrels; not really a big component of their diet. But diet and cover is just one of many aspects of what marten need to thrive.

Does anyone know their range and density in WI prior to being lost? There are two areas in WI that have been the base areas for our re-introduction. I have not read up about marten needs or habitat, so I don't know if the population density is too low for adequate recruitment and growth or not. We do have several blocks of wooded areas in northern WI that should be large enough for marten regeneration, but success has been limited for sure. What are flora and fauna differences between our northern mixed hardwood, pine, spruce, hemlock than what is classic boreal forest?

Bryce

I don't live in a boreal forest. I'm not sure that really is a requirement.

Geez you Alaska guys know how to have a "discussion". Well thought out responses based on scientific evidence and personal observation and not even a hint of a jab at one another. Well done Gentlemen!

I have read about the importance of red backed voles in good marten populations(maybe other voles in other places) and I believe they are more habitat specific as well and need deep snow packed loose duff to survive well. But as Gulo points out Animal population under great stress can sometimes make successful behavioral and habitat adaptations that they might not have if not forced. One example is the now Freeway Red-tailed Hawk population around the Mpls/St Paul metro. There is one sitting on about every tenth light pole because they have learned how to live in that niche and pass it on. But adaptation is not always successful for all species hence extinction.

In the Cascade Mountains of Washington, there is a distinct elevation line where marten just don't seem to descend below. That line is generally highest in California and gradually decrease as you go northward. In most of the areas I trapped marten in Washington, that elevation is about 3200 feet, some places (especially north facing slopes) it is somewhat lower. One place in particular was less than 2000 feet, but it was defiantly a micro-climate area.

The thing that is noticeable, is that the tree species generally change from Doug fir/hemlock to hemlock/true fir as you go up in elevation. As soon as you hit that zone of true fir (silver and noble), and it was in old growth, particularly with a lot of downed logs, you would then find marten.

These higher elevations have more precipitation and much more snow cover. but studies have shown that martens favourite prey, the red back voles lives in equal abundance in the lower elevation trees stands and the high elevation trees stands. So it's not the feed that is the limiting factor.

My opinion is that marten need a certain moisture content in the soil and their environment in general for some strange reason. Coastal range marten, which are quite scarce nowadays, are found nearly at sea level, but then that is a wetter environment. They are a finicky animal.

One thing that you have to remember when thinking about marten, unlike mink which breed in their first year of life, marten don't reproduce until their second year. And they generally have fewer kits than do mink.

X2, NY’s Adirondack fisher population is diminishing and the Marten population is expanding. Here on NY’s Tug Hill Plateau the fisher population is high, so few if any Marten. I caught 7 fisher trapping while deer hunting. Although I did see a Marten track here while deer hunting and others say there are a few here on Tug Hill.

I remember leaving the Herkimer trappers convention some years back headed home. I saw a road killed marten along the highway not very far from the fairgrounds. The first I had seen in the wild.

As far as the elevation thing goes..........where I trap the base elevation is around 350 feet ASL with a few spots reaching 1100 or so. The only time I see marten at the tops (above timberline) is when it is very cold in the valley. They move up to try to stay above the inversion. We've probably all seen that.
Your mention of different flora and moisture makes me think about all the time I spent trying to figure out why there were lots of marten on one end of my line and very few on the other. Same latitude, same altitude, same vegetation........BUT very different soil types. One end was rocky, sandy, mostly igneous terrain The other was loamy with mostly sedimentary and metamorphic rock. Much deeper soils that certainly hold moisture better than the sandy stuff.
The end with the better soil had a marten density (based on my capture rates) of probably 8 or 10 times what the other end had.

I agree with you that squirrels don't make up much of a marten's diet. Way back in the mid-1990's....Gulo set me up with a microscope at my line cabin to explore stomach contents of marten.

The overwhelming majority of pieces I could identify in the gut were red backed voles. There were parts of grouse feet and a very few shrews.....not many. I don't recall ever finding any part of a squirrel that I could identify. Could have been there but mixed in pretty well with other hair and meat

No doubt , DEC biologists recovered a road kill Marten in Rome, NY a few years back.