Field Fun Friday

Two Canada lynx kittens from a family of five captured on a remote camera in Kluane, Yukon Territory last summer. When food is abundant, lynx have big families, like this one. When food is not abundant, females have fewer kittens or may forego having kittens altogether. Kittens stay in their mother’s den for several weeks after birth in May. In the peak of the summer, they begin to explore the world outside their den. This camera captured images of the family on one of its first trips out of the den.

Females will soon be establishing new dens and having new litters of kittens in Kluane. Food is abundant for lynx in the study area, and researchers expect big families again this year.

Photo and post by Darcy Doran-Myers.

Winter Fieldwork in the Yukon

The winter! the brightness that blinds you,
The white land locked tight as a drum,
The cold fear that follows and finds you,
The silence that bludgeons you dumb.
The snows that are older than history,
The woods where the weird shadows slant;
The stillness, the moonlight, the mystery,
I’ve bade ’em good-by—but I can’t.
– Robert Service, “The Spell of the Yukon”

Field assistant Bailey, Kluane resident Peter Upton, and Bubba the dog snowshoe across the ice on Kluane Lake.

I spent January of this year in the boreal forests of Kluane, Yukon. My goal was to collect pictures, fur samples, and tracks of Canada lynx in order to estimate density of lynx in the Kluane area. My Master’s project compares methods of density estimation to improve lynx research and management. Every few months I head to my field site in Kluane. I have experienced every season of the year in the Yukon, from the midnight sun in summer to the deep dark and cold of winter. No time of the year is quite like January. 

Most of my time in Kluane, regardless of season, is spent hiking. This becomes particularly challenging in winter. This year, temperatures dipped to -35 Celsius and snow was thigh-deep in many places. Bailey (my field assistant/ hiking buddy) and I looked to lynx for advice on how to traverse long distances in deep snow. Lynx have disproportionately large feet, making them look funny in summer but helping them keep up with their prey in winter. Their feet function as snowshoes to distribute their weight and help them float on top of the snow. So, Bailey and I got some snowshoes. Not just any snowshoes; modern, lightweight snowshoes were ineffective in snow that deep. In order to make it to all our remote cameras and fur snag sites, we had to borrow extra-large, old-school snowshoes from a local outdoorsman. After a steep learning curve where we learned to walk without tripping (sometimes), the snowshoes became indispensable to our everyday hikes. 

Bailey and I in our snowshoes, on a long hike through a frozen creek bed. We set out this day to collect lynx fur samples from a snag. (Photo by Lindsay Potts)

Cold temperatures were less easily dealt with. Lynx grow big fur coats every winter, with a beard around their neck for a scarf and thick fur between their toes for boots. All Bailey and I could do was outfit ourselves in the human-made substitutes. No matter how much we layered up, we still lost heat throughout the day and had to manage it as best we could. When temperatures were low, lunch breaks to eat our (frozen) sandwiches were limited at five or ten minutes, or until the cold caught up to us. Taking off our mittens even briefly to check cameras or to make a note was painful. Camera screens wouldn’t work, handheld GPSs would turn off mid-hike, and even pen ink would freeze. The Yukon cold did not make our fieldwork easy.

A Canada lynx notices a remote camera set atop a ridge in Kluane.

Despite the deep snow and the deep cold, Bailey and I headed outside each day to take advantage of every hour of daylight available. A key lesson that I learned this field season is that tough conditions are not as tough when you have a friend by your side to experience it all with you. Long sunrises and sunsets, Northern Lights to light up the night, and expansive white landscapes can help counter the extreme conditions with extreme beauty. And the real reward for the tough times was a lot of data. We collected about 250 pictures of lynx and 100 fur samples for analysis in that month. Every successful camera or fur snag and every lynx track in the snow is another piece of the puzzle to understanding lynx populations and improving our management of an ecologically, economically, and culturally important wildlife species.

The sun rises at 10 AM and lights up the sky above the Alaska Highway.

I will return to Kluane for the last time in June. I look forward to experiencing yet another side of the North. By June, everything will have turned from bright white to bright green. The winter challenges of cold and snow will be exchanged for mosquitoes and mud. Long days will keep me outside for hours on end, and I look forward to returning to camp every day tired and happy. But I will certainly miss the Kluane winter and everything it offers. Again in the words of Robert Service:

There are hardships that nobody reckons;
There are valleys unpeopled and still;
There’s a land – oh it beckons and beckons,
And I want to go back- and I will.
– “The Spell of the Yukon”

Dream team.

Darcy Doran-Myers

Using playback of territorial calls to investigate mechanisms of kin discrimination in red squirrels

A little while back, I did a Master’s degree at the University of Guelph with Prof. Andrew McAdam. I worked on the Kluane Red Squirrel Project, a collaborative project between several universities in Canada and the U.S. This long-term project was started nearly 30 years ago by Prof. Stan Boutin at the University of Alberta. The project has involved many undergraduate, graduates, and post-docs over the years studying a variety of ecological and evolutionary questions on a population of red squirrels in Kluane, Yukon.

  • A red squirrel in Kluane, Yukon, one of the individuals in the study population.

For my Master’s project, I was interested in red squirrel territorial behavior and the vocalizations, known as rattles, used to defend their territories. Red squirrel rattles are individually unique and have been shown to be used to discriminate kin, though the mechanism underlying this ability is unknown. In a recently published paper in Behavioral Ecology, I sought to distinguish between the mechanisms of ‘prior association’, where animals learn the phenotypes of kin they associate with early in life, and ‘phenotype matching’, where animals use a template to match phenotypes, thereby allowing them to recognize kin without an association early in life. I recorded rattles from squirrels in the field, and used those recordings in playback trials to measure the behavioural responses of squirrels to rattles from familiar kin, unfamiliar kin, and non-kin. One of the major benefits of the Kluane Red Squirrel project is that there is pedigree information for each squirrel, which means that we know who their mother and father is and who their siblings are. Without this information, this project would not have been possible, and full pedigree information is difficult to obtain for wild populations of animals.

  • Recording rattles from squirrels in the field to use in the playback trials

For red squirrels, familiar kin consisted of pair of squirrels that shared a natal nest (e.g. mother-offspring pairs and siblings from the same litter), and unfamiliar kin consisted of pairs of squirrels that did not share a natal nest (e.g. father-offspring pairs, siblings from different litters). Initial analyses revealed that red squirrels did not discriminate between familiar and unfamiliar kin, but also did not discriminate between kin and non-kin, despite previous evidence indicating this capability. Post-hoc analyses showed that a squirrel’s propensity to rattle in response to playback depended on an interaction between relatedness and how the playback stimuli had been recorded. Rattles used as the playback stimuli were either recorded from squirrels as they moved freely around their territories (unsolicited), or from squirrels as they were released from a trap or in response to a broadcast rattle (provoked). Red squirrels discriminated between rattles from close kin (relatedness coefficient of at least 0.5) and rattles from less related kin or non-kin (relatedness coefficient of less than 0.5) when the rattles were recorded from provoked squirrels. Squirrels did not exhibit kin discrimination in response to rattles that had been recorded from unprovoked squirrels.

This figure show the probability of a rattle response from the subject squirrel during the playback period by relatedness coefficient calculated from the pedigree and the collection method of obtaining the rattle stimulus. Unsolicited rattles were recorded from squirrels moving freely around their territories (n = 67 trials), and provoked rattles (n = 38 trials) were recorded from squirrels as they emerged from a live-trap or from squirrels responding to a rattle playback

This is potentially quite interesting, but it is important to note that this relationship was identified through exploratory post hoc analyses and needs to be tested more rigorously. If these results are robust, however, they would suggest that a squirrel’s physiological state might influence the structure of its rattles, including those individually distinctive structural features that are presumably used in discrimination. This raises interesting questions about what kind of information may be contained in the rattles and suggests that rattles may reflect the current state of stress or aggressiveness of the squirrel.

Photos and post by Julia Shonfield

Julia Shonfield, Jamieson C. Gorrell, David W. Coltman, Stan Boutin, Murray M. Humphries, David R. Wilson, Andrew G. McAdam. 2016. Using playback of territorial calls to investigate mechanisms of kin discrimination in red squirrels. Behavioral Ecology arw165. doi: 10.1093/beheco/arw165.

The abstract and a link to the full text can be found here:

If you are unable to access the article but are interested in reading it, you can email me at julia.shonfield@gmail.com and I can provide you with a copy.

 

 

 

 

Field Fun Friday

Spruce grouseThis striking male spruce grouse was spotted in the boreal forest in the Yukon. In the spring you can hear the sounds of their displays as the males show off for the females at the start of the breeding season. This one was photographed by Jessica Haines while she was working with the Kluane Red Squirrel Project.

Field Fun Friday

Male red squirrel killed by a bird of prey in Yukon during the breeding season in 2013. Photo by Jessica Haines

Male red squirrel killed by a bird of prey in Yukon during the breeding season in 2013. Photo by Jessica Haines

A male red squirrel killed by a bird of prey in the Yukon. He was found far from his territory during the breeding season, likely looking for breeding opportunities (ie. checking out nearby female squirrels). Thanks to the snow you can see the hole where the bird caught him, then bird tracks leading to the spot where he was eaten. We occasionally find red squirrels killed by predators and try to use evidence at the kill site to tell who did it. It’s not common that the tracks are so nicely laid out like this – this story was pretty clear. Goshawks and great-horned owls are the main avian predators of red squirrels in this part of the Yukon, while lynx is the top mammalian predator.

Post and photos by Jessica Haines, taken during her fieldwork with the Kluane Red Squirrel Project.