Fast furious and frenetic, yet gracefully choreographed, are my words for the evening out-flight of the Orient Land Trust bat colony. As day yields to night, the voices of the 25 of us gathered at a fence above the opening of the old mine shafts—now the bat caves—are hushed as we await the 'opening act.' Rapid click-click chatter noises begin coming from a device that a Colorado Division of Wildlife employee is using to monitor the bats' activities. Soon, several forerunning bats open the gala and communicate to the cave that the coast is clear. Let the out flight begin!
Within minutes, squadrons of bats, numbering in the hundreds, fly in waves at high speeds, darting, maneuvering, and winging into the deepening darkness on their way to the smorgasbord of insects that await them in the San Luis Valley. We are standing at a fence with the bat caves below us, a mountain ridge above, already black against a rapidly darkening sky, but, allows enough of a lighter background to see the bats. These are Brazilian Free-Tailed Bats with eight inch wing spans. Individual bats are silhouettes against the sky, blurred by their numbers, their speed, and the oncoming darkness. People are speaking in whispers, some facing the west into the valley to see the flight, others, like me, looking just above the ridge line to the east to catch the action as the bats emerge. Even with the numbers of bats flying, I hear no sounds from their wings and the sonar they use to 'see' in the darkness, are at frequencies that humans cannot hear. In a word, the scene, as an Italian might say, is fantastico!
Even with a bright half-moon directly above us, it became too dark within 15 to 20 minutes to see any bats. Plus, the smell of bat guano is strong and it is not the most pleasant of odors. Thus began our night-hike back down the trail to Valley View Hot Springs. The moon provided enough light on the rough and rocky terrain to make the use of flashlights unnecessary. It made for a nice walk and good conversation.
Bat Night to me, when I was a kid, meant going to a St. Louis Cardinal baseball game and all the kids under a certain age received a free baseball bat. (I still have two!) Or, seeing an occasional little brown bat flying around our midwest neighborhoods on muggy summer nights going out to feast on their dinner. I make reference to these, as there were several children at the out-flight and I was thinking back to when I was about their age. The old iron mines had been abandoned in 1932 but it was not until 1967 that this colony was discovered. Seeing the bats in '67, I would have been in childhood awe and thought it was way cool. But now, as a wildlife ecology person, (ecology being defined as the science of living organisms and their relationship to each other and their environment), my mind began to wander to the term ...
Defined as an impulse to travel or restlessness combined with a sense of adventure. It is a genetic trait and it certainly makes up a part of my intellect. Think of explorers and adventurers throughout human history and the word becomes clear.
Animal species also have individuals with this trait. It helps a species survive by expanding its range of places to live. The Orient Land Trust (OLT) bat colony is an off-shoot of the bat colony from Carlsbad Caverns in New Mexico, a natural cave several hundred air miles to the southeast. The OLT bats are males (estimated population between 100,000 to 250,000) unlike the breeding colony in Carlsbad with males, females, and babies. Learning more about the bats from our evening guide, he mentioned that these bats are designed for both speed and long distance. Two questions came to my mind: 1 - How many scout bats flew north to the San Luis Valley and discovered this mine (their new 'boys only digs’ aka; man cave) and when? 2 - Why is this not a breeding population?
1) Was it like a Star Trek expedition where numerous bats set out intentionally to find a new cave for creating a new colony, or was it one bat with a serious case of wanderlust who found the Orient Mine caves and went back to Carlsbad with the good news? That is a question without a known answer. But, the cave is a good summer home (mid June to September) and there are plenty of night flying insects, courtesy of the Agricultural industries in the valley.
Moths, mosquitoes, and other flying insects are there for the bats to eat.
2) To answer the question about why is there no breeding population, I can go back to a college class in Field Biology and Ecology. The next concept is known as a Limiting Factor - (think money - "I would have a garage full of fast Italian sports cars, except, I don't have the money for the garage OR the cars!" - I am a writer, not a real estate developer.)
Though it would seem to make sense for this species (Tadarida brasiliensis) to have a breeding population at the Orient Mine - the following limiting factors are possible:
- It is too cold for babies to survive in the Colorado mountains.
- Though there is plenty of adult bat food in the SLV, there may be a food supply source in Carlsbad that is essential for young bats to live.
- It is also possible that the bats do not spend enough time at their summer home and that young bats could not make the return flight back to Carlsbad and continue onward to Mexico and South America for the winter.
I could be way off. There may be another variable that answers question #2. But, the Orient Land Mine summer home for boys does allow for maximum numbers of bats to survive without exhausting the summer food supply in southeastern New Mexico.
Further knowledge - Do an internet search for bats. Amazing creatures! Go to the Orient Land Trust website for info. (olt.org) on dates and times for out-flight guided tours. The tour is more than the out flight. Mine history, human history, remnants of the small town of Orient, an old railroad bed to ship the iron ore to Pueblo, and other fascinating history surrounding mining and life in the communities that served the industry is all along the walk.