What the #$*! Is a Sky Island?

''different islands to a considerable extent are inhabited by a different set of beings.'' Darwin

Sky Islands - Remnants of a Vast Mountain Range

I am going to go way out on a limb here. That’s right folks, read on and you will see how a liberal arts major explains a complex and scientific topic. I know that my nature-smart friends are cringing right now—but let me try.

Here Goes

First off, see the map above with the Rockies extending down to the Sierra Madres in Mexico? Lots of really high bumps there, right? Well, when you get down to the Southern Arizona part it is mostly flat, with the exception of scattered bumps. Well those bumps in the middle of all the flat are called Sky Islands.

Nature Switched Things Up

The folks who actually know what they are talking about, say that some 15,000 years ago, real forests stretched from the Rockies down into the Sierra Madres of Mexico. Treasures of a different sort such as wolves, black bears, grizzlies and jaguars as well as squirrels, birds, reptiles and insects moved along a lush, wooded corridor. Or so we imagine it. The same for tree and plant species – they spread the entire length courtesy of the wind and animal poop. But that was a cooler era then today. When temperatures rose, rainfall dropped, and the lower elevations of Arizona started to look like a desert. In some places, high mountain desert.

Elevation and Water

Wildlife that needed water, (and who doesn’t!) and cooler temperatures, like squirrels and frogs, soon found themselves marooned at higher elevation spring-fed canyons. Thousands of years of isolation of the cooler and wetter high ground evolved into what we now call “Sky Islands”.

Exotic Sky Island birds like this Elegant Trogon

Darwin May Differ

Here comes the part where I arm-wrestle with the Galapagos Islands: “Sky Islands” here in Southern Arizona are just as special, if not more so in some ways (I’m going out on a limb here!), than the Galapagos. Because while all the islands in the Galapagos share the same climate, Southern Arizona is unique. In “our” sky island chain, every thousand feet up that you climb takes you into a climate that's more like one some 500 miles north -- a few degrees cooler and with a few inches more rain. So as I hike through the Huachuca Mountains, I am at alligator juniper at 4,000 ft, oak at 5,000 and Rocky Mountain ponderosa pine forest at 6,000. In some of the higher Sky Islands, like the Huachucas, Pinalenos and Chiricahuas, the forests above 7,000 feet resemble those of the Pacific Northwest with aspen and occasional Douglas fir. In some sky islands you could stand on the top of a mountain amid a stand of aspens and with a strong enough telescope see out to the saguaro cactus type desert below. Try THAT in the Galapagos.

Sky Islands are near-paradise for nature lovers like me. Birders go nuts, and it is a mecca for migrating exotic species. Over 275 species of birds, some of them REALLY beautiful and rare, like the Elegant Trogon which looks like it escaped from an Aztec headdress.

Scientists say that these Sky Islands are right behind Costa Rica in biodiversity. And not all those mammals are the little desert shrew variety. Which are vital to the cause but frankly, don’t bring me much wildlife viewing pleasure. In our mountains you can still hike or bird and have a chance to see mountain lions, black bears (small but quick), ring-tails, bobcats, coatimundis, mule deer and a cute little white-tailed variety called the Coues' deer. And the very rare spotting, by a lucky few, of the occasional jaguar and ocelot venturing in from Mexico. Plus there are 60 species found nowhere else on the earth. “Rare to the max” I like to say which doesn’t sound as scary as "Endangered". Even isolated from similar species on other sky islands. Just like in the Galapagos! But closer and no passport required.