Months after Harvey, see how the bat colony is faring at the Waugh bridge
For years fluttering, flying black creatures of the night were stars every dusk under the bridge they called home. Thousands of Mexican free-tailed bats would emerge from their rest under the bridge in search of food to the delight of dozens and dozens of onlookers.
Hurricane Harvey changed all that.
Back in December the Houston Chronicle's Maggie Gordon revisited the colony, ravaged by raging floodwaters that took over Allen Parkway.
According to Texas Parks and Wildlife biologist Diana Foss, the colony at one time was home to over 300,000 bats.
Less than half had returned in the months after the hurricane. The crew's nightly flight in search of food, once an awe-inspiring festival of guano and flapping wings, was just a skeleton of its former self. Still no less a marvel to watch, the diminished numbers were nonetheless troubling.
But according to Foss, the bats are coming back now in full force as spring warms up. Their numbers are increasing. Just as the city has bounced back, so have the bats.
"The bats are examples of the 'Houston Strong' motto – they survived and are doing extremely well," Foss said Tuesday. "Given some time, the colony will be huge again. The emergence is still really wonderful."
According to Foss, the Mexican free-tailed bats that migrated elsewhere for the winter are back under the Waugh bridge now.
"A few stragglers are still arriving," she noted. "Pregnant females will be giving birth to their one pup, starting at the end of May, and going through most of June."
Even with diminished numbers, Foss said, that sunset display is still a sight to see. It's an example of wildlife maintaining a status quo even inside a bustling urban area.
"They exit the bridge on the east side in short bursts most nights, rather than in long streams across the sky. They're still exciting and well-worth the trip to watch," Foss said.
The population of bats is estimated to be around 100,000. How do you count bats?
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"Every number given is always an estimate," Foss told Chron.com.
There is a scientific method, requiring expensive equipment and thermal cameras. The thermal camera is attached to a computer that counts each heated blob as it flies by.
A cheaper method involves dividing the area under the bridge into quadrants and simply counting. Clipboard, pencil, binoculars and a datasheet are used with one person spotting and counting and relaying information to an assistant. Those counts are done during the day as the bats rest.
Foss said there is also another interesting component to the bat sightings. Nature has a way of adding drama to the mix when it can.
"Pre-Harvey there was a colony of night herons, along with several hawks, that were catching and dining on bats each night," Foss said. "Those dispersed during the Harvey flooding. But now at least one hawk visits the bats each night. It's all a part of nature – the bats try to out-maneuver the hawk and the hawk does its best to zip in and catch a bat dinner."
Animal life, as with its human counterpart, is slowly but surely getting back to normal in the wilds of Houston. Just give it time.