A great egret flies to it's nest at Brackenridge Park along the San Antonio River.
A great egret flies to it's nest at Brackenridge Park along the San Antonio River. Credit: Scott Ball / San Antonio Report

Bill Pennell is assistant city manager of San Antonio’s Parks and Recreation Department. What people might not guess about his job is that it regularly requires overseeing bird evictions.

This week, the latest phase of the City’s struggle against the egrets that congregate along local waterways is happening along the San Antonio River in King William. There, a regular population of 30 egrets swelled to more than 200 in only a couple of days, as migrating birds begin to join members of their kind who roost along the river.

The goal is to keep the birds moving along, separating into smaller clumps, and dispersing throughout the city. Without the dispersement, Pennell fears that number could swell to 1,000 as nesting season gets underway.

“That area of the River Walk, if it’s got 1,000 birds in there, it’s going to be not a place anybody’s going to want to be,” Pennell said. “Homeowners that are going to be right underneath where these birds are at are not going to be happy.”

To harass the birds and get them moving to new roost sites, City workers brought along lasers, clappers, screamers, and bangers. Clappers are essentially two piece of wood that make a slapping sound when smacked together. Screamers and bangers are both pyrotechnics – one makes a screeching sound, while the other shoots in the air and pops like a bottle rocket.

Parks officials expect the noise-making to go on between 4 and 8 p.m. starting Thursday and continuing for three to four days.

In a time when life in San Antonio seems turned upside down because of the coronavirus, the struggle to manage the roosting behavior of hundreds of cattle egrets, snowy egrets, tricolored herons, and green herons is a holdover of City routine from simpler times. The City has long tried to keep down bird populations at Brackenridge Park, among other parks.

Late last year, the City and the U.S. Department of Agriculture used similar harassment techniques to evict egrets and herons from their rookery at Bird Island in Elmendorf Lake Park. According to City and Joint Base San Antonio officials, the birds were frequently crossing runways at Kelly Air Field on their way to and from a South Side landfill they used as a feeding site.

The influx of birds in King William is tied to that removal from Elmendorf, Pennell explained. But not in the way one might expect.

Before last year’s evictions, Elmendorf Lake Park was home to around 200 to 300 permanent resident birds, he said. But during spring migration and nesting seasons, when out-of-towner birds returned to familiar rookeries at Elmendorf, the total population could swell to anywhere from 1,000 to 1,200, he said.

Last year, the City and USDA were able to successfully move the 200 to 300 resident birds to new roosting sites on the Southwest Side, Pennell said. No longer do these birds cross runways and stick in the craws of local officials.

However, the remaining 700 to 1,000 migratory birds, those that left Bird Island for warmer climates than San Antonio, are now starting to return to the city with intentions of nest-building and chick-raising.

Over the weekend, the first group of about 150 to 200 birds came through Elmendorf Lake Park, Pennell said. USDA staff kept them moving.

“When they saw them come in, they did their clappers and lasers and pyrotechnics, and the birds moved on to go find another place.”

Those birds kept flying east, where they discovered other members of their species roosting along the King William area, the 30-or-so year-round residents whose presence was either appreciated or unnoticed.

“Those 30 birds turned into 200 birds overnight,” Pennell said.

Pennell said he has received some comments from King William residents asking why the removal is necessary and saying they appreciate the birds there.

Parks officials are now trying to get those birds to disperse before nesting begins, when federal protections under the Migratory Bird Treaty Act kick in. The act prohibits anyone from harassing, killing, or otherwise harming birds when they have nests with eggs in them.

Most people don’t know about the Migratory Bird Treaty Act. It’s something Pennell has had to learn on the job.

“I’m a landscape architect, but I guess I’m getting to be more of an urban biologist,” Pennell said.

Brendan Gibbons

Brendan Gibbons is the San Antonio Report's environment and energy reporter.