Where flying squirrels go to count sheep...

I tracked squirrels to find their nest cavities, which I then measured (eg. volume, the direction the opening faces, opening area). Flying squirrels are secondary cavity nesters, which means they use cavities excavated by another species, such as a woodpecker.

A regular cavity looks like the one on the right. If you're lucky, once you track a squirrel to its tree you can hit the tree with a stick and a squirrel will either stick its head out of the cavity or actually run out and up the tree. If you're REALLY lucky, you may even get a glide right out of the cavity to another tree. That's always fun to see :) If you look really closely, you can see the nose of a squirrel towards the bottom of the cavity circle.

But then sometimes northerns shrug convention and do this to me. It's not new news that flying squirrels build leaf nests. It was just a little unexpected given the cold winter temperatures. Southerns do not even build leaf nests this far north. So when I stumbled upon my first nest, I thought it would likely be an outlier. But then I found more and more leaf nests...

So that brings us to this winter. This winter I collected several known leaf nests from last winter and deployed them with temperature loggers to look at the difference between outside (ambient) temperature and temperature inside the nests.

So far analysis of that temperature information shows that leaf nests are likely equivalent to tree cavities for buffering capacity. Stay tuned for more rigorous comparisons soon.