Austin’s urban bats pour out into the warm summer night

[youtube http://www.youtube.com/watch?v=injnpYJnQyM]

One of the factors attracting almost 4000 ecologists to downtown Austin in the middle of a hot Texas summer, I’m sure, are bats. Urban bats. Not the high-tech gizmo-laden kind from comic books, but tiny furry creatures that emerge from their urban lair in the heart of Austin every summer night to wreak vigilante justice on insects! Its a remarkable phenomenon: a breeding colony of some 1.5 million bats roosting under/inside the heavily trafficked Congress Avenue bridge smack-dab in the middle of the city.

What an amazing example of reconciliation ecology in practice! A bridge retrofit in 1980 resulted in structural changes that created crevices underneath the bridge which led to hollow spaces inside. Perfect habitat for the Mexican Free-tailed Bat, which soon discovered the swank new dwellings—a rent-free, safe, roomy dwelling, overlooking a fabulous river view, plenty of food nearby, and a safe environment to raise kids n teach them how to catch bugs; what’s not to like?—and moved in in droves. After initial fears and concerns about these seriously misunderstood creatures, fears that were allayed by Bat Conservation International, Austinites settled into an easy coexistence with the little creatures, which have continued to return to the bridge every spring from their winter homes in Mexico, to raise new broods by the hundreds of thousands. BatCon’s website has more about this colony’s history and social / economic significance.

This morning I had gone out early to see the bats return to roost in the dawn. I returned in the evening, with my iPad, to see the more remarkable phenomenon of mass emergence at night. The above video is the result – watch it full screen in the highest possible resolution (480P) for the best view. The clip starts a bit slow as I was waiting for the show to start along with a patiently sweating throng under the bridge. The bats started streaming out from the below the far end of the bridge first, so they are a bit hard to see – squint at the lowest strip of the sky near the lower-middle of the screen to see the stream. Keep watching, though, because soon enough more bats came out from right over our heads, and I managed to catch multiple streams pouring out into the evening sky, and a nice view of the sunset too! You’ll also hear the clicking of the bats as they navigated their way around the struts of the bridge, and squeals of delight and amazement from the watching humans.

Watch closely, and you might also notice a curious pattern to their flight under the bridge – the bats on the northern end of the bridge (where I was) wend their way around the struts and pillars supporting their bridge all the way to near the southern end where they then take to the sky as part of the main stream of traffic! I wonder why, except for once or twice during the peak of flow, they don’t just leave the bridge at once instead of joining that single stream. Mysterious and fascinating.

Later, talking to a volunteer docent from Bat Conservation International on the bridge, I learnt that the numbers were probably at the highest for the year because mama bats had weaned their pups of this spring, and were bringing them out to sample the night’s delights!

What a wonderful experience to watch this remarkable natural phenomenon happen right in the middle of a major urban area. And how amazing to see the wonder on the faces of humans crowding the bridge (some 8 million come to watch them every year, I’m told) for a glimpse of bats on a hot day. If this is possible in the middle of Texas, with all its rattlesnake-round-ups and evolution-denying schoolboards, surely we can find other ways to accommodate other wildlife in the midst of our own habitats now blanketing most of the land.

Watching the bats, mamas, pups, and all, drawing such a human crowd, with many a child gaping in awe… what a perfect way to end the ESA meeting, which had as its main theme: Earth Stewardship! There may yet be hope for our species and cohabitants of spaceship Earth, it seems…

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