Some of the most interesting stories come from the bats mailing list.

This one is out of Southeast Arizona, a biodiversity hotspot south and east of Tucson. It’s a birding Mecca, a naturalist’s paradise.

I went looking for birds, but it also bubbles with mammals, reptiles, and insects. Coming back to our campsite one evening after a lovely day of birding, we found insect buffs shining lights onto white sheets spread out over a picnic table. Attracted by the light, huge beetles shot out of the night and flew plonk into the sheets.

It doesn’t pay to be exclusively bug-minded. Near there, I began clambering up a small rock face. My companion stopped me. On the rock, above head level, what appeared to me to be a good handhold had appeared to a miniature rattlesnake to be a good place to sunbathe. It had been rattling to warn me off, but I took its tiny rattle for a buzzing insect.

A friend who was collecting for museums (he had permits), filled his VW bus with aquaria, jars, and bags full of amphibians and reptiles, perhaps including all 13 species of Arizona’s rattlesnakes. When pulled over by law enforcement – for being a hippie in a VW? because they sought migrants without papers? – he explained his job. He agreed they could search the car. The officer slid open the side door. It stuck, then flew open with a bang. Thirteen species of frightened rattlesnakes went off like a rifle range. The officer ran to his car, leaped in, and drove away at top speed.

Hiking up a gully in search of Five-striped Sparrows, I put my hand on a small palm tree. A bat who had been sleeping under a bark scale on the palm rocketed out in mortal terror.

Strolling up a mountain trail in quest of birds, we saw a bear and cubs strolling down. We decided to veer off to one side. She decided to veer off to the other side. Our collective tact avoided awkwardness.

On the road toward a place that has hummingbirds like a dump has flies, a coatimundi came galloping down. It had been chased away from some trash, and if such things were possible, it would have been giggling.

Not just a paradise, an interesting paradise. A complex paradise. A rich, dense, millefiori paradise.

That’s why the American Museum of Natural History’s Southwestern Research Station is there. I wish I had an excuse to take their intensive week-long bat course.

Why is this place so biodiverse? It’s a desert. Yeah, but it’s a subtropical desert. It’s where everything comes together. Eastern, western, northern, and southern species meet here. Species come down from the Rockies, up from the Sierra Madre Occidental in Mexico. Two great deserts, the Sonoran and the Chihuahuan, meet. Low mountains form the “Sky Islands,” with stacked habitats from saguaros to conifers. There are two (modest) rainy seasons that different species can take advantage of. (So: wildflowers.)

Humans flock there. Logically, an area so rich that it contains rose-throated becards, dragonfly geeks, twin-spotted rattlesnakes, javelina hunters, Underwood’s mastiff bat, astrophysicists, Gila monsters, museum collectors, beardless tyrannulets, birdwatchers, and coatimundis, surely cannot lack for aggressive paranoids.

Sure enough! Ferocious folks in military gear! But we already had plenty of those.

Southeast Arizona is next to the border with Mexico. The U.S. Border patrol interprets “border” very lavishly, so that you can be camping many miles from Mexico and be woken by the light of a thousand suns when the Border Patrol decides to inspect your bona fides. You won’t get away with camping in non-official spots, or sleeping in your van. (What if all the campsites are full? Keep driving, pal.)

Recently self-important volunteer “militia” in places like Colorado have decided to go down and help the Border Patrol repel illegal immigration. They got even more excited at the thought of large numbers of children fleeing Central America crossing the border.

Uninvited, some of these big talkers have made their way to the borderlands to posture in paramilitary gear. Some wore Tshirts reading “Undocumented Border Patrol Agent.”

Late one August night, in Gardner Canyon, near Sonoita, a few heavily armed wanna-bes from Colorado figured they’d found their first perps, quietly moving along a ridge in the darkness. Gardner Canyon? Oh yes, this Birder’s Guide says Gardner Canyon is “a good place to find Montezuma Quail and Botteri’s Sparrows.”

They shone spotlights on the miscreants. Cleverly, they shouted at them in Spanish to identify themselves. They ordered them to sit down and wait. They announced they were a militia group protecting the border.

The sneaky night walkers shouted back that they were conservation scientists engaged in a wildlife survey. Counting bats. They kept walking toward their camp. But they did so “while seeking cover.” For some reason. The spotlighting kept up.

“We didn’t know what they were doing. We started hiding behind rocks. We’re not doing what they’re saying, and they’re acting kind of jumpy,” one researcher said. “We had them yelling at us with spotlights, acting like they have some kind of authority.”

The militia called the Border Patrol to announce the suspicious activity. Border Patrol agents went to a campsite where the scientists were staying and identified them as “a small group of biologists studying bats.” They met the militiamen, noting that they were more heavily armed than the agents.

The militamen and the scientists had also met at the campsite, when the militiamen, decked out in camo, pulled up on an ATV, and shouted an apology.

The apology was not accepted. In a complaint filed with the sheriff’s office the next day, one scientist said he “cursed them out and let them know how they had made him and his colleagues feel.” He told them they shouldn’t be out there.

“They weren’t very receptive about the apology. They actually told them that’s something you should not be doing. There’s danger out there. There’s other groups of people in campsites,” said Sheriff Tony Estrada.

The sheriff later told Tucson News Now the county “does not welcome border militia groups.”

“These people… really don’t know the area. They don’t know the terrain. They have little knowledge of the dynamics of the border. So it can be a real problem. We really don’t want them here,” he said.

He’s right. Those guys probably wouldn’t know a Montezuma Quail from a Scaled Quail.

Tragically, no one seems to have recorded the exact words of the apology that wasn’t accepted. I am forced to guess. I think it was a bad one, Probably they apologized for the wrong thing, in the offended party’s view. They were probably apologizing for their error of mistaken identity. Not for rambling around, heavily armed, looking to pick fights.

“Sorry we mistook you for fierce, blood-sucking Central American children! It was dark! We didn’t know you were scientists! Actually we sort of thought you could be drug dealers – no offense. You were acting so sneaky!”

Memo to self: Wear lab coat next time you bird in Arizona.