Monday, April 28, 2014

When is a desert not a desert?

Our son Gawain and his girlfriend Heather recently moved from San Francisco out to Tucson, which is an easy two-and-a-half-day drive from our home in NE Arkansas. That means we have the pleasure of visiting them more often, plus the added perk that their new city is surrounded by my favorite Sonoran Desert.

We left here for Tucson 29 March. I like driving across country, seeing the gradual changes in land forms and vegetation, stopping at rest areas and walking around the edges looking for unfamiliar insects and birds. For the first part of the trip we don't have much choice but to go on I-40, flat and at this time of year mostly drab, not leafing out yet. But not without surprises. For instance, in some parts of the Texas panhandle you seem to see the 19th-century changing directly into the 21st-century.

Windmill farms stretch in all directions as far as the eye can see (quite a way in the flat prairie). I have heard that conservative oil state Texas is going for 30 percent renewable energy.

Anyway, as you approach the border into New Mexico the land abruptly changes into mesas and canyons and high juniper forests. Before you reach Albuquerque you can finally get off the interstate and begin following two-lane roads southwest through increasingly spectacular scenery, rock formations in every imaginable color.

We reached Tucson at a nice time of year. There had been recent rain, and the desert was blooming. And here the terminology needs to be cleared up. The colorful boulders and rimrocks and bajadas and arroyos we had been driving through were partly so visible because often there was no vegetation obscuring them. It really was desert, often the only growing things being dried and stinted yellow grass. That all changed on approaching Tucson. There are still spectacular mountains and so on, but what steals the scene is the rich vegetation. One by one cacti of every shape and form begin to join the setting, from the tall saguaros and ocotillos to the various chollas and prickly pears of the understory. It's like a planted and well weeded garden, a specimen plant, then well tamped sand around it, and then the next specimen plant. Here's an example of the ensemble:


And here are some of the big waxy cactus flowers:

In fact technically this desert, the Sonoran Desert, is not a desert. Real desert does not have all this vegetation and the monsoonal rains that support it. This is thorn scrub or thorn forest, a very different thing.

We spent most of our week in Tucson walking the trails through Saguaro West National Park and Saguaro East and Sabino Canyon and all the other wonderful parks which surround the city. We followed dry washes up, and that was the best way to see wildlife.

 Nesting Cooper's Hawks were common, as indeed they seemed to be in the city itself.

Our very gentle and sweet Brown Thrasher was replaced in Arizona by several thrasher species, but the commonest was the Curve-billed Thrasher. This one coming up to check us out seemed to have a rather ferocious eye, but I expect everything has to be tough to survive in this beautiful but thorny place.

We were hoping to see some of the area's famous rattlesnakes but didn't find a one. We did however see one very nice serpent species. Cheryl and I arrived at a place part way up Mt. Lemmon (on the edge of Tucson) one morning about nine, and I looked down at our feet and there was a four-foot-long snake that was an unripe-banana yellow in color. We were so surprised by the unlikely color that we missed our chance to take a picture. We looked it up later, and it was a Green Rat Snake, fairly special, I think, with not much known about it, except that it's nocturnal, but can be seen around twilight, and then again in the morning until about nine o'clock (which is exactly when we watched it disappear).

One snake we did get a picture of was the Sonoran Gopher Snake, the attractive local race of the common western gopher or bull snake.

Lizards of many species were abundant and easier to find than the snakes. Here is a Zebra-tailed Lizard.

When we or some other dangerous animal come too close it suddenly curls up the last quarter of its tail like someone pulling on a Christmas-parcel ribbon, revealing the black-and-white banded underside, and takes off running full speed. A predator giving chase focuses on the curling-and-uncurling black and white tail tip, and ends up with that in its mouth while the lizard disappears under a rock.

The  Desert Spiny lizard, on the other hand, looks fierce enough that it doesn't even need to run.

We saw the endangered Arizona Pupfish, the little extremophiles that live in scalding hot thermal pools. But this was cheating, we saw them in an artificial pool of normal temperature set up in one of the parks. Still, here they were living happily and in the midst of courtship, the bright males after the drabber females.

One special day Gawain and Heather took us out into the desert after dark. We wore our head lamps, and they had given us little black-light flashlights. It had been discovered by scientists that when you shine ultraviolet light on scorpions they fluoresce, so that you can spot them from a distance in the darkest desert night. Well, we looked very hard for scorpions but it was still rather cool, in the 60's, and no scorpions were out, but we were seeing other things with our head lamps. First it was small rodents racing around at our feet. They were numerous, and not very afraid of us, but moved so fast it was hard to get more than half of them in the picture at a time. But we could see that they ran around on their hind legs, balancing on their long tails. They were Ord's Kangaroo Rats.

Then Cheryl called out that she had seen a big spider, but before we could get over and see it, it had taken two steps and disappeared down its burrow. But we soon found another, and then several more walking across the floor of the desert. No, we didn't scream in horror and run for the car. This was the spider I was most interested in finding: Hogna carolinensis, the largest species of my favorite group, the wolf spiders. This species is instantly recognizable by its brown "mustache." It seemed to me it also had a pleasant grin on its face.

I might have ended my post with this smiley face, but there is one more thing I want to add. Our friends Pat and Dennis Braddy now live in Tucson, and one night we went to their place for dinner. Pat had found a drowned scorpion in their pool and saved it in a bucket because she knew I would be interested in it. She brought it out in its bucket and almost jumped out of her skin when we all realized at once the scorpion had made a total recovery and was facing us with his tail and pincers raised.

We responded just as you would have: We whipped out our black-light flashlights to see if he would really fluoresce. And he did.

It wasn't the seriously venomous Bark Scorpion (which we very much wanted to see) but the commoner and milder Striped-tail Scorpion, and I decided on the spot to keep it as a pet. I brought it home and set it up in an aquarium and it is getting along fine on a diet of beetle larvae. It has, I think, quite elegant table manners.