Very pleased to share my 2nd paper w/ @KluaneSquirrels, spearheaded along with @DFofFreedom & April Martinig! We used the project’s longterm data to look at variation in juvenile survival over three decades. What did we find? Pictures + thread below! 1/18 http://doi.org/10.1111/1365-2656.13209

As with any work on the Kluane Red Squirrel Project, none of this would be possible w/o the support and generosity of Champagne & Aishihik First Nation on whose traditional territory our study site is located. We are extremely grateful to them & strive for meaningful connection.

Some red squirrel background: these little tyrants are fiercely territorial & can’t stand intruders on their turf. It's all about cached spruce cones; white spruce makes up most of their diet, and as they don’t hibernate ( #badass) these middens are key for overwinter survival

So for any juvenile to make it through their first winter, they have to defend a territory of their own. As you might expect, territories are limited so many don’t make it. On average ~80% of juveniles die before one year of age, but there’s quite a bit of variation in this! Why?

For this study, we focused on juveniles that we knew were still alive in August of their birth year, excluding those that may have already died earlier in the year. We know who was alive at this time b/c KRSP does spring and fall population censuses (in the Yukon, August = fall!)

Some of these juveniles had already claimed a territory by the August census, while others were wandering around, still alive but not yet settled anywhere. How this 'fall territory ownership' affected overwinter survival was what we were most interested in.

August census is at the start of caching season. So this isn't an arbitrary date: juveniles that had a territory at this point would be able to cache the cones produced that year. But if they get one later, they can't take advantage of that year's cone crop. #BiologicallyRelevant

Kluane has a wealth of ecological monitoring, so along with squirrel data we also had Environment Canada weather records of winter temperatures, and snow track counts of predator species to get lynx and weasel abundance (phone-through-binos pic of lynx I saw squirreling in 2017!)

So what did we find? It turns out that having a territory in August is super important for surviving to spring: juvenile squirrels with territories in the August census were 2.4x more likely to survive the winter! But we also found some interesting indirect effects...

Chiefly, predator abundance had a stronger effect on non-territory owners. If you’re wandering around trying to find a home in the winter, you’re probably more susceptible to lynx or weasels. Lynx abundance had no significant effect on territory owner survival...

... while weasel abundance had a stronger effect on juveniles without territories in August. This interaction wasn't as strong as for lynx: we suspect that nests & tunnels protect territory owners, but these are more effective against lynx than weasels which fit in these spaces!

Territories also mediated how winter temperatures affected juveniles. Territory owners had lower survival in colder winters, as you might expect. We predicted that non-owners would be even more vulnerable to cold Yukon winters, where it regularly goes well below -30C. But…

... It’s actually reversed! In colder winters, survival *increased* for juveniles that didn't have territories by August (although on average, they still survived worse than territory owners). What’s going on here?? We’re not honestly sure.

One idea: higher mortality of territory owners is actually good for those that don't have one yet. Perhaps squirrels dying in colder winters opens up vacant territories that these floaters can settle on, which helps them survive better. This is still speculation though!

What's the takeaway?
1) Getting a territory early is the priority if you want to make it through the winter
2) This is particularly important when there are lots of predators around
3) Winter weather affects you differently if you don't have a territory in the fall

As much time and energy as my coauthors and I put into this project, there are so many other people who contributed. The data we used to answer these questions was collected by literal hundreds of KRSP technicians since 1989 who've tagged juveniles and conducted censuses...

... and the predator ecological data, first from the ten-year Kluane Project, and later as part of the Community Ecological Monitoring Project, run by Charles Krebs & Alice Kenney ( https://www.zoology.ubc.ca/~krebs/kluane.html).

And that's my (not so) brief summary of this paper! Very glad to see it out in the world. If you have any questions about this research (or need a non-paywalled pdf) please hit me up! Five years of my life working with them & I still love talking about these little miscreants

if it wasn't clear from this summary, I'm pretty into long-term research. This is the kind of paper that needs decades of data to do properly. If you're keen on longterm research & want to get involved, check out https://www.ltr-csee.com/  for anything long-term in Canadian EEB!