Wolverines & Pussy Tails: but wait it’s not spring yet!

When I see willow stems with series of fuzzy little heads peeking out to greet the sun, I think of wolverines. That’s when I know it’s spring. I also know wolverine moms are busy at higher elevations looking after their kits.

I first noticed these pussy willow out on 26 January 2014. It's not supposed to be spring yet!!
I first noticed these pussy willow out on 26 January 2014. It’s not supposed to be spring yet…

But not this year, it’s all mixed up. The weather this month has been crazy. There was very little snow, lots of days above 0oC, and several days of rain. While I flatly refused to take out my umbrella, I did slide into the habit of leaving my gloves at home and wearing my fall jacket. We don’t do that in January in Smithers—or we didn’t. Not when and where -20oC and colder is a fact of life.

The kicker was on January 26th when I noticed pussy willows—yes, that’s right pussy willows. Furthermore, they looked like they had already been out for a few days. Pussy willows don’t do that in January in Smithers—or they didn’t. That’s not until the early days of spring, in late February or March.

The coldest temperature this month was -8.7oC coldest temperature this month; that is, up until yesterday, which was -17.5oC. We have a few more days of cold in the forecast. It will be interesting to see what that means for my symbols of spring. I’m guessing those particular pussy willows won’t complete their reproduction this year.  And I can’t help but wonder what this will mean for wolverines and their reproduction, this year and in the future.

 

A Bit About Wolverines

Of members of the weasel family that live on land, wolverines are the largest. They also have the largest feet, relative to their body size, acting like snowshoes in soft, deep snow. No hibernation period needed for these tenacious critters. They’re masters of winter survival, but more about that in another post.

This is more like the January that I know. Photo by R. Weir.
Now this is more like the January that I know. Photo by R. Weir.

Like others in their family, they have a cool reproductive strategy called delayed implantation. They breed in June through August. The fertilized egg develops into a blastocyst (8 cells) that floats freely until winter when it implants into the wall of the uterus and embryos develop. Females give birth to an average of two kits in February–March. Kits are born tiny (100g–145g), immature, and pretty much helpless with eyes closed. A fuzz of white fur is what they get for built-in protection from the elements.

Kits are born in natal dens, in tunnels dug by mom deep into the snow pack. While relatively few dens have been excavated to learn what they are like, some that have been were elaborate features, and some of these with multiple branches. Tunnels up to 50 m in length have been documented. Mom has her work cut out for her to keep kits warm, dry, and safe for nine to ten weeks until they are ready to start traveling with her. Sometimes she will move them to another den or a sequence of dens; these are called maternal dens. Mom sometimes travels great distances to find food for herself, while returning frequently to feed them, as I learned flying telemetry surveys searching for radio-collared wolverines for the Northern Wolverine Project, in the Williston Lake area, in central British Columbia.

 

Persistent Snow Cover: Potential Climate-Related Effects on Wolverines

Persistent, deep snow cover in spring is thought to be a critical factor for denning; hence, a limiting factor for their geographic distribution. Climate change is predicted to threaten wolverines throughout their range by reducing wolverine habitat (for denning in spring) and associated loss of connectivity (ability for individuals to move between subpopulations).

Around here, most if not all wolverine natal and maternal dens are likely in the subalpine and alpine areas. With little snow and unseasonably warm temperatures, for the first time ever, pussy willows didn’t bring joyous warm feelings of spring. On the contrary, they made me I wonder how wolverines that are about to give birth any day now are going to manage this spring, and more importantly in decades to come, in this region (Skeena Region) and in areas to the south. In 2013, the Pacific Climate Impacts Consortium predicted a 56% reduction (mid-point of projected values) for spring snowfall by the 2050s. Now that is something that I think is worth reflecting on.

 

Check Out these Sites for Some Photos of Wolverines

Check out a female wolverine with her fuzzy white kits at:

Wolverine Foundation: http://wolverinefoundation.org/reproduction/

And don’t forget where you can find lots of stunning photos of the weasel family, including wolverines:

Phat Weasels on Facebook: https://www.facebook.com/PhatWeasels

 

For More Information on Wolverines:

Created and maintained by leading wolverine researchers, the Wolverine Foundation is the best source of information about wolverines, certainly in North America and probably in the world. More than 600 literature references are provided on this site. Visit The Wolverine Foundation: http://wolverinefoundation.org/

If you live in British Columbia, check-out the Pacific Climate Impacts Consortium. A series of brochures have been produced for the eight resource regions in B.C. They provide information about past climate and future projected changes. Visit: [btn Pacific Climate Impacts Consortium: http://www.pacificclimate.org/

 

References:

Copeland, J.P. K.S. McKelvey, K.B. Aubry, A. Landa, J. Persson, R.M. Inman, J. Krebs, E. Lofroth, H. Golden, J.R. Squires, A. Magoun, M.K. Schwartz, J. Wilmot, C.L. Copeland, R.E. Yates, I. Kojola, and R. May. 2010. The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution? Can. J. Zool. 88: 233–246.

McKlevey, K.S., J.P. Copeland, M.K. Schwartz, J.S. Littell, K.B. Aubry, J.R. Squires, S.A. Parks, M.M. Elsner. G.S. Mauger. 2011. Climate change predicted to shift wolverine distributions, connectivity and dispersal corridors. Ecological Applications 21(8):2882–2897.

Schwartz, M.K., J.P. Copeland, N.J. Anderson, J.R. Squires, R.M. Inman, K.S. McKelvey, K.L. Pilgrim, L.P. Waits. 2009. Wolverine gene flow across a narrow climatic niche. Ecology. 90(11): 3222–3232.

The Wolverine Foundation. 2014. Website: http://wolverinefoundation.org/ (accessed 31 January 2014).

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