UTSA study finds large variety of bird species live in San Antonio, bolstered by backyard bird feeding

AUGUST 1, 2024 — Bird feeding is a commonly practiced recreational activity in urban areas in the United States, resulting in a multi-billion-dollar industry. According to ecologists, urban development is frequently found to have negative effects on diverse bird communities, and whether bird feeding can increase the presence of our feathered friends in urban yards remains unclear.

UTSA master’s student Amanda Lamberson searched for answers. She attempted to understand the effects of bird feeding in urban areas and the impact it has on avian abundance and diversity in San Antonio.

“I have a big interest in urban wildlife,” Lamberson said. “A big part of my interest is wanting to know more about how we, as humans, interact with species that live in our yards — how those species are impacted by us and how we can benefit them.”

“One of the ways that people engage with birds in urban areas is through backyard bird feeding. But what does it do to the avian communities in our backyards?”

The inspiration for Lamberson’s project came from her faculty advisor, Jennifer Smith, an assistant professor in the UTSA Department of Integrative Biology. Smith’s doctoral studies included research on the effects of backyard feeding on bird behavior and its impact on breeding success in the United Kingdom.

“One of the ways that people engage with birds in urban areas is through backyard bird feeding,” Smith said. “But what does it do to the avian communities in our backyards? That's an important question for understanding why urbanization is affecting bird populations.”

San Antonio’s climate and its growing urban footprint offered Lamberson the ideal opportunity to explore the effects of bird feeding in urban areas on birds.

“Most of the studies looking at backyard bird feeding had been focused on non-urban areas and in temperate regions,” Smith said. “Urbanization is increasing, and in the U.S., San Antonio is the fastest urbanizing city in the country at the moment.”

In November 2019, Lamberson embarked on the first phase of her study. She enlisted 36 backyards, mostly located on the northside of San Antonio, and recruited volunteers as “citizen scientists” to help maintain the feeders and assist in conducting bird surveys for the next three months.

She was thorough in every detail. She examined commonly used bird feeders and measured the appropriate height of each feeder. She considered the feeders’ density in surrounding yards and learned about the most used bird seed in the community to inform her research approach.

“Dr. Smith and I and a few volunteers consistently collected data, but we also had residents who volunteered to collect data as a way of encouraging ownership,” Lamberson added.

The backyards were broken up into three groups with 12 homes providing mixed seed, 12 providing Nyjer seed and 12 homes serving as a control group without providing any seed. Observations were made on a strict schedule every two weeks during a 16-week period during two winters.

“By counting the birds, we could determine what the abundance of birds was, and what the diversity was,” Lamberson said. “Then when we took away the food across all the yards the following year, we could assess how the birds responded.”

But before conducting the second phase of her study a year later, Lamberson encountered an obstacle no one expected: COVID-19.

“A lot of people were very wary of closely interacting with anyone,” she said. “So that impacted how many people were able to continue to participate.”

Continuing the research in the middle of the pandemic required flexibility and quick decision-making. Lamberson said 13 of the 36 original backyards were not monitored during the second phase of the research, but it didn’t stop her from seeing the study through.

“There's a number of traits that make someone a good wildlife ecologist. Being resilient, being resourceful, being able to think on a spot are huge skills,” Smith said. “Amanda’s ability to be resourceful, and navigate these challenges, especially in the face of COVID, were really impressive.”

Ultimately, Lamberson and her team counted 6,088 birds from 40 different species during both phases of observations, results that re-affirmed Lamberson’s hypothesis that backyard bird feeding attracts a wide array of birds, even in urban areas.

“We often think about reduced diversity and species richness in response to urbanization, but beyond just the feeding component of Amanda's project, our results showcase that there are a lot of different bird species in urban areas.” Dr. Smith said.

The Lesser Goldfinch appeared more than other birds during the observation period, especially in Nyjer-fed yards. Surprisingly, the frequency of their appearance did not change once researchers stopped providing food, which introduced new questions for the researchers to answer.

Despite the ups and downs of conducting the study, Lamberson is thankful for the community support in completing this research and is proud to leave her mark in the world of avian ecology. It’s knowledge that will prepare her on her next journey as a biologist for the U.S. Fish and Wildlife Service.

“Science is just like a big puzzle, and you're missing a lot of pieces,” Lamberson said. “So getting to be able to contribute to that puzzle and go, ‘That's my piece. This piece of knowledge that fits into this huge framework of this world.’ It's really humbling and I’m really proud to get to contribute to that.”

— John Elizondo