Travelogue: The Sky Islands of southeastern Arizona

In just a few weeks I’ll be moving from Prescott, Arizona to the Santa Monica Mountains in Malibu, California. I’m looking forward to the move but there are a few things I will miss about living here. One of the things I’ll miss the most is the opportunity to travel to the Sky Islands in the southeastern corner of the state. This is one of the most biologically interesting areas in the country, and one of the best places for butterfly diversity. Each of the isolated mountain ranges houses a slightly different inventory of butterfly species but all of them boast a wonderful checklist of species that are normally found only in Mexico. For a butterflier, this is a bucket-list destination. I’ve only lived in Arizona for two years but have managed a few trips to the Sky Islands. Each trip has been memorable.

On these trips we’ve visited several different areas that are famous for their butterflying opportunities. If you plan on visiting the area, and invaluable resource is Bailowitz and Brodkin’s Finding Butterflies in Arizona:  A Guide to the Best Sites. Be aware that fires have damaged some of the places mentioned in the book, so things aren’t always as described. Still, it has great information on what to expect at various localities, how to access the different regions, and the amenities present at each. We’ve used the information in this wonderful guidebook while exploring Madera Canyon and its nearby environs, Sycamore Canyon (one of my favorite places on earth), Mt. Lemmon, Patagonia, and the Huachucas. On this, our most recent trip, we went to several of these places and weren’t disappointed. But for this post I’m going to focus on one of the most famous ranges, the Chiricahuas.

But first, a quick explanation because by now, the uninitiated among you are probably wondering what the Sky Islands are, exactly. Sky islands are isolated mountain ranges, each surrounded by distinct lowlands, and each potentially housing endemics (species or subspecies that are unique to an area), and/or relics (an organism that used to be widespread but is now confined to a narrow distribution). Sky islands often house a great deal of biodiversity, and have become targets of conservation efforts as we humans expand our reach across more and more of the planet. Sky islands are predicted to become even more important as climate change begins to impact species’ ranges- species confined to mountaintops may not be able to withstand changing climatic conditions, while other species may begin to move upslope.

We arrived at the Portal entrance on the east side of the Chiricahuas in mid-afternoon and decided to head to the American Museum of Natural History’s Southwestern Research Station. The SWRS has a long and venerable history of hosting biologists and other researchers who study this remarkable place. It also hosts numerous courses and workshops throughout the year where students, scientists, and other interested folks can spend some time learning about a specific topic. During our visit the SWRS was hosting an ant course.  On a hunch I inquired as to whether Terry McGlynn, who blogs over at Small Pond Science, might be there.  I was pleased to find that he was, and I delayed his lunch briefly to introduce myself and make plans to get in touch when we move to LA.

The SWRS allows visitors on part of the grounds. The main draws are the hummingbird feeders and the butterfly garden. As a former birder married to a birder, I enjoyed spending some time watching the hummers battle it out at the numerous nectar sources available. The most exciting species while we were there were the blue-throated hummingbird . These suckers are large, showy, and incredibly aggressive. Most hummingbird species are fairly territorial and aggressive, actually, but these animals were particularly unwilling to share their resources, despite, in this case, numerous feeders as well as nectar-producing flowers.

The hummingbird feeders are the main attraction for most folks, but I, of course, was more interested in checking out the visitors to the butterfly garden. During our trip the main nectar sources appeared to be verbena and milkweed. Lots and lots and lots of Northern Cloudywings, Thorybes pylades,  were taking advantage of the blooms. I checked as many of them as I could to see if any of them were actually Valeriana Skippers, Hammock Skippers, or any of the longwing skippers, but no dice. All of the large, dark skippers make up a challenging group. Most non-butterfliers would probably assume, based on their relatively drab coloration, that they are not butterflies but rather moths. This is actually true of a lot of skippers, not just the large, dark spreadwing group. Skippers are an acquired taste, but for the butterfly enthusiast, few things pose a more enjoyable challenge to ID.

Two other potentially challenging species were making an appearance at the garden that day- Monarchs and Queens. Both species lay eggs on milkweed, and the caterpillars feed on the foliage as they develop. They are able to take advantage of the milkweed’s toxicity, sequestering the cardiac glycosides into their bodies without harm. This provides them with a chemical defense against predators. The Queen and the Monarch are Müllerian mimics (more on mimicry later!), warning predators of their toxicity through a bright color signal (aposematism). Because both species are giving an honest signal, warning predators not to eat them, when they can coexist in the same area they’re actually helping each other out- the two species look so similar that if a bird (or other predator) eats a Queen, it will remember the bad taste, associate it with the color pattern, and avoid both Queens and Monarchs in the future. The same is true if it encounters a Monarch first. During our visit we saw several adults of both species, as well as several large (late-instar) Monarch caterpillars busy munching milkweed.

In 2010 a human-caused wildifire, the Horseshoe Fire swept through part of the Chiricahuas southwest of Portal. The fire destroyed several thousand acres of this beautiful area and cost millions of dollars in damage. Then, in 2011, tragedy struck again. The Horseshoe 2 Fire began in early May and wasn’t completely contained until late June. Over 220,000 acres burned during this fire, costing well over $100 million in damages. Dozens of buildings, including homes and businesses, were destroyed. This fire, too, was human-caused. The ecological impact to the range is still being assessed, and it will most likely be many years before the full extent of the damage is understood.

Should you ever decide to take a trip to the Sky Islands you won’t be disappointed.  The monsoon season, late summer, is my favorite time to go.  Not only does the vegetation start to turn lush, but Madrean butterflies and birds move north with the rains, coming up from Mexico and giving the observant butterflier quite the treat.  There is lodging available in most of the ranges, but camping is easy to do there as well.  Don’t let the heat scare you- the monsoon season is one of the best times to visit Arizona.

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