For biologists, it is not uncommon for a research project to take years of field observation before the findings prove meaningful, but some take even a little longer than that.
For 44 years, University of Tulsa Professor of Biological Science Charles R. Brown has been conducting research at sites in western Nebraska on cliff swallows, an American bird with broad pointed wings, squared tails, and small heads.
Cliff swallows are highly social birds, among the most colonial in North America, and live together in groups of mixed sizes, akin to humans congregating in cities. Brown’s research regarding the costs and benefits of living communally was recently featured in a major paper published in the journal Ecological Monographs.
“The cost of being social is automatic: parasite spread, disease spread, food competition, etc. If you don’t have a reason to be social, you shouldn’t be,” Brown said. “We wanted to understand why and how group living in these birds evolved.”
One benefit of cliff swallows living in groups was the sharing of information among colony residents about successful foraging sites. However, Brown’s findings show that this behavior has mostly ceased. “In the 1980s, foraging groups were a major advantage for cliff swallows; they could help each other. But suddenly we noticed that they weren’t foraging together as much. They were still living in colonies, but their foraging was asocial,” he explained.
Brown said this is likely the consequence of a decline in the population of flying insects in the area, but it is hard to determine since accurately sampling insects is very difficult.
Another finding was that, over a relatively short four decades, the cliff swallows had evolved shorter wings that enabled them to avoid being hit and killed by vehicles along the highways where they now make their homes. “That attracted the most attention out of all the research,” Brown said. “I’m now most known for roadkill.”
His research is supported by generous funding from the National Science Foundation. Through the years, he’s recruited around 80 students in total to assist in research, from undergraduate to graduate to post-doctorate. Together, the teams have caught approximately 400,000 cliff swallows, banding 220,000 of them for permanent identification.
Amy Moore was an undergraduate when she began working with Brown on the cliff swallows project 20 years ago. “Working with Charles is life changing. He has high expectations, but is kind, thoughtful, funny, understanding, and most of all, motivational,” she said. “Another notable attribute of Charles is his effort in launching the careers of many scientists. Cliff swallows will be his legacy, but the way he has lifted and launched the careers of young, budding scientists I feel is just as important.”
The project traces back to Brown’s years as a graduate student at Princeton University, when he began investigating cliff swallow activity on the Nebraska plains. He notes that those birds are likely the ancestors of the ones he is studying today.
In addition to his feature in Ecological Monographs, Brown will soon publish his experience with cliff swallows in a book that he hopes will appeal to both biologists and non-technical readers. “We’ll see how successful I am in threading that needle,” he added with a laugh.