It’s almost spring, and that means the City of San Antonio has launched its annual effort to dissuade migratory birds from nesting in certain sections of Brackenridge Park.

City parks department officials say the goal is to reduce the potential health impacts to visitors caused by the feces of concentrated colonies of cattle egrets and other migratory birds by discouraging some percentage of them from roosting near Joske’s Pavillion and the San Antonio Zoo.

During nesting season, the birds’ feces thickly coat areas below and nearby nests, including picnic tables and playground equipment. The smell is overpowering, and the excrement can carry respiratory diseases, cause algae blooms that kill aquatic life and raise levels of E.coli in the San Antonio River.

Bird mitigation, as city officials call it, includes making the targeted areas inhospitable by clapping wooden blocks together and shooting off small pyrotechnics. Efforts also include removing old nests, opening up tree canopies and using lasers or balloons as visual deterrents.

All of those methods are legal and none are lethal, said Texas Parks and Wildlife Department biologist Jessica Alderson.

“The city and its inhabitants enjoy the birds, we want to see birds — but the overall management plan is for the safety of the public and the safety of the birds,” she said. “It’s better for them to be away from people. Brackenridge is a 300-acre park — we’re not wanting them necessarily out of the park, just out of the areas where there’s a lot of human activity.”

Mitigation activities began last Friday and will run through the end of March, said Grant Ellis, the natural resources manager for the department. The city is getting an earlier-than-usual start this year. Efforts were curtailed last year when the birds began laying earlier than expected.

Once birds nest and lay eggs, mitigation must cease because they are protected under the Migratory Bird Treaty Act of 1918, which prohibits their capturing and killing.

The city had also hoped to begin construction last year on the 2017 Brackenridge Park bond project. The fate of that project became inextricably entwined with the nesting birds, however, as city emails showed that the parks department saw the removal of dozens of trees as a boon to bird mitigation efforts.

Snowy egrets nest in trees above Brackenridge Park on Tuesday.
Egrets nest in trees in Brackenridge Park in Spring of 2022. Credit: Nick Wagner / San Antonio Report

The city ultimately apologized to residents after months of denying the connection.

As it has in the past, the city has contracted with the U.S. Department of Agriculture and coordinated with the Texas Parks and Wildlife Department and U.S. Fish and Wildlife Service to do the mitigation work.

Alderson, who began working with the city on bird mitigation efforts at the park in 2015, said the city remains committed to using nonlethal methods.

Some lethal methods are legal, she noted, but “since I’ve worked with them to now, their biggest concern has always been not to use lethal force.”

That commitment has not assuaged some residents, who have accused the city of waging a “war on birds” inside the park. They point to city emails in which city staff and USDA officials discussed using such methods in 2019 at Elmendorf Lake, and have accused the city and its hired contractors of illegally killing fledglings and harming eggs in the park.

Texas Parks and Wildlife has found no proof of foul play, Alderson told the San Antonio Report Monday.

“Our game wardens are always kept up to speed and any complaints we get are taken very seriously,” she said. “The complaints have been proven to just not be true. Things happen in nature — sometimes nests get knocked out of trees by wind, or there’s the natural mortality people see but it’s more apparent because it’s happening in a place where more people are concentrated.”

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Lindsey Carnett

Lindsey Carnett covers the environment, science and utilities for the San Antonio Report.