Tuesday, March 8, 2011

Winter Watering Hole

As ACES naturalists, we often get to see--and share with our guests--signs of winter animals while on the trail.  However, due to the nocturnal or crepuscular (active at dawn and dusk) habits of many of these animals, we rarely get the chance to see them in action.  Last night I was given a rare opportunity to see one of these elusive animals on the prowl in my own backyard.

Several miles up Castle Creek Road, SW of Aspen, my cabin is remote and mostly undisturbed by human activity.  Running alongside the cabin, buried under several feet of snow, is a meandering creek that opens into a small pond. Due to the current, the pond seldom freezes completely at the inflow, providing a vital watering hole for many overwintering animals.  Throughout the winter, the morning has often revealed a flurry of tracks--snapshots of their nighttime ice capades.  Last night, with the aid of an infrared, motion-activated camera, I caught a glimpse of this activity.  Much to my surprise however, the cavalcade of winter animals that I had envisioned, turned out to be the mere work of a solitary red fox.


Although omnivores, in the winter, red foxes depend largely on the small rodents living beneath the snow pack in the subnivean zone for food.  Locating a mobile food source, often buried under a meter or more of snow, foxes have to cover a lot of ground.  Once a prey animal such as a vole or mouse is found, the fox utilizes its acute hearing to pinpoint its depth and location. The fox leaps high into the air and using its tail to direct its flight, dives into the snow, trapping the animal.
To see a video of this in action, click here.


From the images I’ve collected, I suspect that the fox behind my cabin has worked out a sort of nightly routine.  It seems to make its first appearance around 9 pm, around the same time that I often begin to settle in and turn off my lights inside. Throughout the night it returns, but only for a few minutes and a quick drink, before heading off in a new direction. By 5 am the visits have ended.

Friday, March 4, 2011

A fresh perspective on Pine Beetles


Last Thursday at Hallam Lake for the Naturalist Night speaker series, Professor Dan Tinker from the University of Wyoming gave a really illuminating talk about some of the science and research going into the Rocky Mountain Pine Beetle outbreak we are witnessing across the West. Living, working, and learning in Colorado nearly my entire life, I thought I had a decent grasp on most of the science looking at the interactions of Beetles in our forests. Professor Tinker quickly dispelled that little notion of mine.
In one hour, he presented the most scientifically sound overview of the beetle outbreak that I have read or heard about since my undergraduate days. One of the more interesting things about his presentation was that he had a much different message about the beetle epidemic than a lot of the articles we read about in national or local newspapers. His presentation wasn't all doom-and-gloom, in fact, it was quite the opposite. His assertion, which he explained quite well, was that many of the forests which are being hit by the beetles are regenerating with young seedlings and saplings as many of the older trees are being killed. There are lots of younger trees surviving even in the wake of massive die-offs and many of the lodgepole pine forests are going to regenerate within a couple of decades. I have hiked through areas in Grand and Summit county and seen the acres of dead trees but you can't help but noticing the young survivors. These young survivors are going to be the next generation of trees in the forest. The future for our forests isn't truly as bleak as some sources make it out to be.
Professor Tinker used the Yellowstone fires of 1988 as a comparative model for the beetle kill, and it was a powerful example of how resilient many forests are. After the massive fires ran through vast swaths of forest, a couple of years later Prof. Tinker and colleagues witnessed many of the areas recovering quite rapidly with young aspen and lodgepole filling in the vacuum left by the fires. If forests can rebound from a massive fire disturbance then it is likely a pine beetle epidemic isn't going spell the end for our forests. He also presented research looking into the likelihood of a forest fire occurring after the onset of a beetle infestation. Many of the findings suggest the beetle-killed trees don't have a significant impact on increasing the probability of fires starting in a forest. That was new information to me.
Prof. Tinker also brought up the conversation of climate change and beetle infestations. Warmer winters and periods of drought have allowed the more beetles to survive winters than in the past and drought is making it more difficult for trees to fend off swarms of beetles. However, trees have a pretty good defense against beetles (forcing them out with a resinous sap) but the blue-stain fungus that the beetles carry in their jaws is truly responsible for killing many of the trees. The blue-stain fungus moves into the xylem (sapwood) layer of a tree and it basically cuts off the flow of water throughout the tree. The beetles have evolved to carry the blue-stain fungus.
Dan Tinker's presentation reminded me that things are not always as they seem, especially in nature. There are always multiple layers at work in ecology and we must remember to look at nature holistically to grasp the totality of a phenomena like a insect epidemic. Its also important to keep in mind that a system in nature (like a forest) can recover from major disturbances like fire and insect outbreaks.

If your in Aspen, be sure to come by ACES at Hallam Lake on Thursday Nights at 7:30 for Naturalist Nights. Its free and continue through the end of March. Thanks for reading!

Thursday, March 3, 2011

Surprises at Hallam Lake

After almost nine months at ACES (has it really been that long?), I'm beginning to feel like I know Hallam Lake well. However, the best thing about Hallam Lake is that there is always something new to find.
Last week, after a lot of snow over the weekend, Robin and I were walking around the lake, shoveling out the platforms and bridges. Coming around the corner past the big blue spruce, I saw something exciting ahead of me.






In the fresh snow, there was an area with a bit of blood on the snow, some small downy feathers, and some wing marks in the snow! There were no tracks around the site, other than the trail, and no tunnels either-- it was a mystery! Robin and I discussed for a while what could have happened- at first we thought a large bird had gotten a weasel that had put up a fight, but without tracks or a tunnel, it couldn't be!
Here's a more close up shot of the scene:



We decided it must have been a large bird killing a small bird. A male golden eagle has been visiting our female all winter-- perhaps this was his meal?
That same morning, there were also beds on the path where a couple of elk had been spending the night.
I'll admit, I was wrong-- there are still lots of things to learn about Hallam Lake!