Saturday, April 26, 2008

Eagle Creek Bat Cave, April 2008

Once home to millions of Mexican free-tailed bats, Eagle Creek bat cave provides refuge still to many thousand bats. In the early 1960s, Dr. E. Lendell Cockrum (University of Arizona) estimated there must be 25 million bats living in this cave in southeastern Arizona. The bats poured out of the cave for 30 minutes each night like a heavy plume of smoke before fading to trails of bat wisps that lingered for another hour or so. The cave is located in a beautiful Sonoran riparian deciduous forest. Seep willow and tree tobacco line the river and the canyon is populated with Arizona alder, sycamore and walnut, netleaf hackberry, Fremont and narrowleaf cottonwoods, box elder, velvet ash, and desert willow. Mesquite, ocotillo and prickly pear remind you that as lush as Eagle creek may be in the spring, this desert riparian area will dry significantly in the summer months. I saw 4 black hawks, soaring and calling against the canyon walls; turkey vultures, flycatchers and even a roadrunner, the tail of a whip-tailed lizard hanging out of his beak like a limp spaghetti. The 6 desert bighorn sheep - no rams that I could see - were a highlight. So beige and blending with the canyon rock I might have missed them if it weren't for their spots of white rump. They stood still up on the rock, not precarious at all, just confident. Beaver sign was plenty, plenty of peeled bark and gnawed sapling stumps. No beavers working this day.

In the early 1900s, the Eagle Creek bat cave was mined for bat guano.
The guano was removed from the cave and packed to the town of Morenci by burro before being shipped by train to a fertilizer company on the west coast. The guano mining ended around 1954, but still present all these years later are large wooden rollers, ladders, and chutes. Also, left by biologists in the 1960s, large cages where bats were held waiting for biologists to crimp metal bands on their wings in hopes of learning where they come from or where they go (capturing them elsewhere), or perhaps how long they live.

Why am I here? To see if there are signs that people have been disturbing the bats and gauge the feasibility of constructing a gate at the cave entrance to prevent access inside. Evil people have been known to shoot guns into the cave, killing the bats or knocking their babies off the ceiling to die on the cave floor. Even the well intentioned curious can do a lot of harm by going into the cave, which rouses the bats to swirl around the ceiling. If they feel especially vulnerable and fly outside, they'll be easy prey by the black hawks I saw earlier. The cave, with its impressive visible opening is not anything special inside. High ceiling but shallow, there's no branches or hidden rooms to explore. The bats are the cave's treasure, and they are best enjoyed while seated outside at dusk. Watching many thousands of bats (hopefully the population will someday again number in the millions) leave the cave to go feed is worth the price of non-admission.

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