Nature's Garden Naturally: Bats and Birds in Texas

This past week, we flew to Texas to attend our niece's wedding in Bryan, and then to spend a few days in Austin. I have only been to the Dallas/Fort Worth area of Texas, so it was nice to see a different part of this big state. In a span of five days we experienced weather extremes from sixty degrees with rain and a threat of tornadoes to sunny and a near record high of 91. Since it snowed back here in New Hampshire while we were away, it was nice to enjoy summer-like temperatures.

Upon arriving at Austin-Bergstrom International Airport we were greeted by the sounds and displays of Great-tailed Grackles. Larger than the Common Grackle, these birds are not shy of humans and enjoy making a display of themselves. Their iridescent black color and yellow eyes are quite striking.

Great-tailed Grackle

Although Texas has some great opportunities for viewing spring migratory birds, we did not have time to do any serious birding. We did, however make a point of walking underneath the Congress Avenue Bridge in Austin to see the bats come out at dusk. The bridge, which crosses the impounded Colorado River, aka Lake Bird Lake, now hosts the largest urban bat colony in the world. When the bridge was redesigned in 1980, the crevices that were created provided prime nesting spots for the Mexican free-tailed bats that migrate to central Texas each spring. After construction, the bats immediately started arriving by the thousands. Irrational fears from the public, led to proposals for eliminating the bat population, including illuminating the bridge. At that time, Bat Conservation International moved their headquarters to Austin and educated city officials on the benefits of bats including the fact that each bat can consume of thousands of insect pests per night. Thankfully, the City listened, and viewing the bats from spring until fall has become a popular tourist attraction.

From the viewing platform underneath the bridge and on the water, visitors await the emergence of the bats.

While we were waiting for the bats to come out, birds were putting on their own show. Behind us, dozens of grackles congregated and made quite a racket before they settled down for the night. Then, across the river, hundreds of egrets landed in a single tree. Due to the distance I could not tell whether they were Snowy or Cattle egrets. Interestingly, both species of egrets and the Great-tailed Grackle are listed among six species of birds that have been identified as having "nuisance" heronries (nesting areas of colonial water birds) in Texas according to the Texas Parks and Wildlife publication Nuisance Heronries in Texas Characteristics and Management. Dealing with large populations of birds is another example of the challenges that occur when the human populated landscape intersects with wildlife. Although most people enjoy and are inspired by the beauty of seeing wildlife, they do not want wildlife to interfere with their daily existence. From the extreme of being a danger to air traffic at airports, to the nuisance of excrement falling on the family car, large congregations of birds may not be well tolerated by society. However, as scientists continue to learn how closely interconnected all species and how disruptions to one species can sometimes cause irreparable harm to entire ecosystems, we need to be careful how we address these issues. As a reminder, the theme for this year's Earth Day is "Protect Our Species." We all must act to curb the massive rate of plant and animal extinction that is occurring across the globe

Flock of Egrets along Lady Bird Lake

Thankfully, for the bats in Texas, organizations such as Bat Conservation International and Austin Bat Refuge are educating the public on how to enjoy and live with bats to help preserve their populations.

After the sun set, the bats began to emerging from underneath the Congress Street Bridge. My small camera was inadequate to capture a good photo, but seeing them in person was a sight to behold. According to the Austin Bat Refuge, 814,000 bats took flight that evening. In August, that number may double when the pups join the air with the adults. It was surreal to look up in the sky and see a large black cloud, knowing that it contained tens of thousands of bats. It's an experience I will not forget.