Okay, all you folks in northern climes who were wondering where your American Robins went, well, you can stop looking: I found 'em. They are all safe and sound and snowbirding in beautiful Sedona, AZ! They say that the trip south was uneventful except for that wrong turn at Albuquerque and a nasty blizzard just as they were traveling through Northern Arizona.

They'll be spending the next few months relaxing and admiring the red rocks from high perches in pinon and juniper trees:

 

If you get down to Sedona this winter don't forget to stop by and visit them along the Jim Thompson or Brins Mesa trails. You might also see some Western Bluebirds as well, which can always be counted on to brighten up your day.

As you can see from the photograph the Chihuahuan Raven looks a heckuva lot like a Common Raven. I was paying close attention during the show and I couldn't pick out any major differences between the Chihuahuans and the birds I see every day on campus. The Chihuahuans seemed a bit smaller but honestly I doubt if I could pick one out of a lineup without comparing photos.

Sibley says Chihuahuan Ravens can be distinguished from Common Ravens by their smaller size, shorter bills, longer nasal bristles, and white feather bases on the neck. Here's a Common Raven from up by Page, AZ for comparison.

If you compare the length of the nasal bristles to the total bill length in both birds the Chihuahuan does indeed have longer bristles. At least they extend farther down the bill - almost to the end - than on the Common Raven. And the Common Raven has a bigger forehead in this picture, but I think that's just the way it's holding its head/feathers than any physical difference in anatomy.

In the following picture I caught one of the Chihuahuan Ravens in the act of eating a bit of meat given to it by a handlers. It picked up the meat with the end of its bill and then gulped it down whole.

The differences between the two raven species is quite subtle, but I think the characteristics to focus on in the field are

• Habitat - Chihuahuan Ravens prefer hot, arid country in southern Arizona and Mexico. Common Ravens can be found just about anywhere. If you're in the desert and you see a raven there's a chance it could be a Chihuahuan. If you're in the mountains it's probably a Common.
• Size - Chihuanhuan Ravens are smaller than Common Ravens.
• Bill Length - Chihuahuan Ravens have shorter bills about the same length as the head. Common Ravens' bills are longer than the head.
• Nasal Bristles - Chihuahuan Ravens have longer nasal bristles that extend comparatively far down the length of the bill vs the Common Raven.
• White feather bases on the neck - If you see white in the feathers it's a Chihuahuan Raven.

The other day I was up on Mount Elden and snapped this picture of Sheep Hill, the big volcanic cone that dominates the east side of Flagstaff:

The distinguishing feature of Sheep Hill is the extensive cinder mining operation that has removed much of the western flank and top of the cone. Because the side of the cone has been dug away you can see the interior of the mountain and its colorful striations, which is kind of cool if you're into geology:

Cinder mines, generally called "cinder pits", are basically just big holes dug into the side of a cinder cone. Heavy machinery scoops up the loose cinders and loads them into trucks. The cinders are then used to provide traction on winter roads, as landscape material, and to make masonry blocks, i.e. "cinder blocks". In a very real sense we are removing these mountains bit by bit and spreading their remains over the surrounding landscape.

Looking at this topographic map that was made thirty years ago back in 1980 you can see that the cinder pits have grown to consume all of Sheep Hill's western flank and shaved the top from the cone. The smaller unnamed hill just to the south of Sheep Hill is almost completely gone. And Wildcat Hill, which should tower almost 300 feet above the surrounding terrain is also all but gone.

This isn't the same kind of mountaintop removal mining (MTR) that's going on in Appalachia but the end result will be much the same.

In my previous aspen post I alluded to the fact that the aspen in Northern Arizona were facing a serious threat unrelated to global warming and tree fungus. In this post I'll outline what that threat is and explore some possible solutions. But before I start digging into Arizona history let's get to know the aspens' main adversary first:

Bull Rocky Mountain Elk in the meadow near Kachina Village. Source unknown.

Surprised that it's not loggers, drying forests, or tree fungus? Yeah, so was I. By far the biggest threat that aspen groves in Northern Arizona face is actually one of the most beautiful and magnificent animals in the forest: The Rocky Mountain Elk. People love watching and hunting elk. When I lived in Kachina Village I remember long lines of cars stopping along the frontage road to take pictures of elk grazing in the fields. I was guilty of this several times and I've got the pictures to prove it. There is just something awesome about elk.

But the problem with elk is that they really, really like to eat aspen. They'll strip all the leaves off a young aspen sapling in seconds and rub the bark off of older ones trying to get the velvet off their antlers. If given free access to a thicket of young aspen they can kill everything less than ten or fifteen feet tall. Unless physically prevented from doing so via an exclosure or steep incline this breaks the reproductive cycle of the grove, resulting in the situation we have now where large, mature aspen trees are reaching the end of their lives with no young aspen to replace them. If you take a walk among the aspen groves along the Kachina Trail you'll see what I mean:

Note how the aspen visible in the above picture are all large, mature trees. There are no saplings or young trees even though some of the older trees are beginning to come down, making plenty of sunlight available. The trees in this picture are not dead - just dormant for the winter.

When I first learned this my immediate question was why is this even a problem? I mean elk (and deer) have been in this forest for eons. Why are they suddenly such a threat to aspens now? The answer was surprising: elk HAVE always been in this forest, but not THESE elk and not in THESE numbers.

It turns out that before the white man came to the southwest there was another species of elk living here called the Merriam's Elk. It was physically larger than our elk today but had far fewer numbers and thus less impact on the forest. It's population was kept in check by two factors: lack of water and a healthy set of natural predators, with water being the primary control. But as settlers and ranchers moved into Arizona uncontrolled hunting forced the Merriam's Elk to extinction. By the early 1900's the Merriam's Elk was gone forever.

Of course not having any elk in the forest was a huge bummer so beginning around 1913 Yellowstone Elk (Rocky Mountain Elk) were imported and released into the woods 45 miles south of Winslow, AZ near Chevelon Creek. All the elk you see in northern arizona today are direct descendants of those original introduced animals. In a way, the big beautiful bucks with huge racks of antlers you sometimes see gathering in the meadows around Flagstaff are an invasive species!

Okay, so introducing one kind of elk to replace another extinct kind probably wouldn't have been a big deal except for the fact that their numbers soon ballooned out of control. There are now far more Rocky Mountain Elk here than there ever were Merriam's Elk so their impact on the forest ecosystems is much heavier. The Rocky Mountain Elk increased statewide from the original 157 introduced animals back in 1928 to some 35,000+ today (2002 numbers). This population boom is one of the largest increases of any large game animal recorded in north america and is the primary reason why young aspen have no chance to grow large enough to survive.

But why did the Rocky Mountain Elk population explode when the original Merriam's Elk population had always remained small? The population boom would not have occurred without a couple of other human-caused factors that happened around the same time. First, as cattle ranchers began using the forests to raise cows they knocked the natural predator populations down. Grizzly bear and wolves - the only predators really capable of tangling with large elk - were completely extirpated and black bear and mountain lion were severely curtailed to protect cattle interests.

Secondly, the lack of water, especially in dry summer months, was overcome by humans building thousands of stock tanks (i.e. dams) across the state. These low, earthen dams collect arizona's infrequent rainwater into small ponds and provide drinking water to thirsty cows and wildlife. They are everywhere in the forest - a simple search in my topographic map software shows more than 2,200 of them within a 50-mile radius of Flagstaff. Statewide there are something like 8,500 of these things! And these are just the tanks with names that made it to the maps. I'm sure there are many more out there that aren't documented.

Stock tank near Sedona, AZ. Note the large dissimilar tree growing in the center of it.

As usual in these types of situations it's not really fair to point the finger of blame at the most obvious agent of change (i.e. the elk). The elk, while undoubtedly the instrument of destruction, are just animals doing what animals do. They try to survive and reproduce as best they can in a tough environment. We mustn't be too hard on them. Instead, the elk are really just scapegoats for the real villain in this drama: human meddling in the forest ecosystem.

Ranchers and others trying to protect their cattle and maximize profits unwittingly removed the two limiting factors for the elk population, namely natural predators and scant water availability. With no natural predators and year-round water elk numbers boomed and now we find ourselves in the current predicament: aging aspen groves with no young trees to replace them. That old adage about the road to hell and good intentions surely applies here.

So what are we going to do about this? We have huge numbers of introduced elk eating away at the future of aspen groves. Wouldn't the easiest way to save aspens be to just reduce the elk population down to more "normal" numbers? And yes, that's the only long-term solution, but it's easier said than done. First, we don't really know what a "normal" population is. And secondly, today we have powerful economic forces in the state with vested interests in keeping elk numbers high. Hunting groups, guide services, sporting goods stores, and even the Arizona Game and Fish department itself make a lot of money from these animals. It's in their own best interest to vigorously oppose anything that would reduce elk numbers. They might be convinced to increase the yearly hunting quota but it's going to be a tough political fight and so far they're not going for it.

Another solution might be to reintroduce natural predators to keep the elk population in balance. That would work, but the people of Flagstaff and the surrounding communities might have something to say about packs of wolves and grizzly bear passing through their backyards. And cattle ranchers would certainly oppose such efforts as the experiment to reintroduce mexican gray wolves in eastern arizona has shown to be the case.

Breaching the thousands of stock tanks scattered throughout the woods might also work. Reducing water availability would surely bring populations down as lack of water was the original limiting factor in the Merriam's Elk population. But suddenly removing water would be a truly horrible and inhumane way to reduce elk numbers as everything in the forest is now dependent upon these water sources. I originally came into this environmentalism thing from an animal rights and anti-cruelty route and even knowing what I know about aspen trees I couldn't support such a thing. It would be just too horrible.

So that leaves us with physically preventing the elk from eating the aspen saplings. This works as the difference I saw between the inside of the aspen exclosures and the outside was quite pronounced. Inside were thick stands of young aspen well on their way to adulthood. Outside were nothing but large, older aspens that took root before the elk got out of control. Exclosures most definitely work but they're extremely labor intensive to build and maintain (as my aching hands and back could attest to last weekend). There are other techniques using deadfalls of downed pines and other unconventional stuff that the Forest Service will be trying besides building tall fences but they are not guaranteed to work as well and may actually do harm. But they have to try something and time is running short; putting up exclosures around every aspen grove in northern arizona is just not feasible.

As you can see, the challenges facing aspen groves are multifaceted and rooted in a couple different historical causality chains. You could almost say that we couldn't have done a better job of dimming the future of aspens here even if we'd purposely set out to do it. With so many interlocking problems and economic forces working together it doesn't look good. But it's also not completely hopeless. Maybe if more people learn about the plight of aspen in northern arizona we can do something about it. Maybe we can preserve a few groves so that in the future, when people eventually wake up to what's happened to the environment and decide to do something meaningful about it, there'll still be a few healthy groves to start fresh from.

Ever since I read those articles on Sudden Aspen Decline (SAD) and spent some quality time hiking in the spectacular but doomed aspen groves on the south and west slopes of the San Francisco Peaks I've been feeling depressed and helpless to do anything about the dim future of these trees. It's a shame that a species of tree that's been growing here since the last Ice Age (and probably even before that) could be all but gone in fifty years. And we caused it. I don't think that's too strongly worded or can be repeated too many times: Because of what humans have done it's entirely possible that in a few generations the only aspen trees left in this part of Arizona could be landscape trees bought at nurseries. The magnificent groves of wild quaking aspens that Arizona Highways gushes about every Fall could be extinct with little left to show that they were here but fading memories and JPEG files on computer hard drives. The thought of that happening makes me sad and, to be honest, more than a little pissed off.

Yesterday I spent the day working with the Friends of Northern Arizona Forests volunteer group to repair and upgrade an aspen exclosure off of highway 180. The work was back-breaking and by the end of the day my arms were limp from carrying heavy 10-foot fence posts a half mile through the woods and my hands cramped from twisting thick wire fencing clips into place. The group of 30+ volunteers were a mix of young people and older folks, all of whom were highly motivated and willing to work hard for a good cause. That so many young people showed up made me feel a little less cynical about the younger generation and the future of the environment. But only a little.

One of the benefits of going out there was having access to Patty Ringle, the silvaculturalist in charge of aspen with the Forest Service. She was full of interesting and enlightening facts about aspen trees, human-caused changes to the forests in Northern Arizona, and strong opinions about how to solve aspen decline. I'll post some more on what I learned later. But for now, let me just say that at least in Northern Arizona tree fungus and drying forests isn't the biggest threat to aspens. Not by far.

I can't express how good it felt to go out into the forest and physically do something to help aspen trees. It was so much better than sitting at home reading ever-more-dire blog posts and articles on climate change and feeling the creeping despair take root. Together we gave those trees a fighting chance to survive. But don't get me wrong, even if what we did yesterday saves that particular 30 acre grove of baby aspens it was only a rearguard victory in the larger war against anthropogenic climate change. To even make a dent in this problem we'd need hundreds - if not thousands - of volunteers and vastly more funds than the Forest Service has so far deemed fit to give to the aspen exclosure projects.

Still, it felt awfully good to get out there and put some sweat and muscle towards saving trees. I'll definitely be doing it again.

In my last post on orienteering I explained how to use a single compass bearing to find your location on a trail or road. With this post I'll show how to use multiple bearings to triangulate your location anywhere, whether you're on a trail or not. This is a useful technique if you're hiking off-trail or have become lost.

Here is a panoramic photo I took from somewhere up on the San Francisco Peaks with three compass bearings in red:

From left to right the bearings are to Freemont Peak, Humphreys Peak, and Aubineau Peak. To determine your location using the compass bearings you first have to convert them to back-bearings and then adjust for magnetic declination. Remember, to convert to a back-bearing you add/subtract 180° to obtain the bearing as it would be for someone standing on Freemont/Humphreys/Aubineau back to your current location. Finally, you add the magnetic declination as determined from your map's legend. This gives you the True North back-bearing which can be used on a topographic map:

Freemont Peak = 223-180+13 = 56°TN
Humphreys Peak = 298-180+13 = 131°TN
Aubineau Peak = 334-180+13 = 167°TN

With the True North back-bearings you can then plot course lines on the map as I've done in the Topo! screenshot below (click for full size version):

The intersection of the three back-bearings points to my location, which turns out to be the Doyle Saddle (no surprise there). The topographic maps all have Doyle Saddle and Freemont Saddle swapped so ignore the label next to the location. When I made the panoramic photo I walked downslope a little to avoid getting too much of the ground in the shot so that's why my location is not precisely in the center of the saddle.

I made the above plot using my copy of National Geographic Topo!, which is very nice software if you're an outdoorsy sort of geek, but not exactly practical in the field. Instead, you'd use a protractor or else orient the map to magnetic north and then use your compass to plot the course lines as I discussed in my previous post. With some practice you can get very close to what Topo! will give you.

This example used three compass bearings but it's perfectly acceptable to use only two bearings. Your accuracy won't be quite as precise but you should be close enough. The third bearing acts as a check on the other two: if instead of converging to a tight point on the map you get a big triangle then you know that one (or more) of the bearings is off.