New Orleanians have long had special relationships with local mockingbirds.
Known for their expansive repertoires, members of the Northern mockingbird species emulate everything from other bird songs to “people sounds,” like whistles. Musicians in the area have taken cues from the birds, signaling each other before gigs with special four-note whistles. And some of the birds seem to take their cues from local musicians. Some residents swear they’ve heard trumpets or other instruments playing in their backyards, only to find feathered friends singing instead.
That mockingbirds pick up these musical sounds doesn’t surprise scientists at Tulane University. The species should be learning new sound patterns all the time. But does lead-heavy soil in New Orleans affect their ability to carry those tunes?
Researcher Renata Ribeiro is tackling that question by examining mockingbirds in two of the city’s neighborhoods. Through a project funded by the Morris Animal Foundation, she is studying the songs of mockingbirds that live in Lakeview, where soil has low lead levels, and the Bywater area, where lead levels are considered to be dangerously high.
Ribeiro suspects that in poisoned areas, she’ll find birds have irreparable brain damage.
“In humans, there are very strong correlations between lead and learning disabilities and even aggressive behavior,” she said. “Are mockingbirds more contaminated with lead learning fewer songs? Or are the songs simpler? Can they not sing very fast? These are the different parameters we’re looking at.”
According to Ribeiro, a postdoctoral fellow of ecology and evolutionary biology at Tulane, it’s important to find the answers to those questions. That’s because the male mockingbird’s singing directly correlates to his ability to find a mate and reproduce.
In other words, the future of the New Orleans mockingbird may be at stake.
“There is a chance females are attracted to males with a larger repertoire of songs, and that may tell the female something about the quality of the male,” Ribeiro said. “They are basically serenading the ladies, you could say.”
In order to study the birds, Ribeiro and colleagues will help residents set up special feeders designed to capture mockingbirds. When one is caught, Ribeiro will collect a few feathers and a tiny bit of blood to test for lead. She’ll mark the birds with colored bands on their legs and record their songs.
By the end of the study, which will conclude in a year, Ribeiro thinks she’ll find birds near the Marigny and Bywater area sing less-complicated songs and show higher concentrations of lead.
Her hypothesis is based on prior research. Scientists elsewhere have discovered that other toxins, such as mercury, can impair memory in various species of birds.
And the experiment isn’t just important for birds. According to Arthur Nead, a Tulane spokesman, one of the main goals of the study is to raise awareness about the problem of lead in New Orleans.
In big cities, flaking paint from old houses that used lead-based paint contaminates the soil. Although the paint is now banned, some houses still have it, meaning the toxins are still being released into the environment.
Tulane has been a driving force for this kind of research for some time. Howard Mielke, a researcher at the Tulane University School of Medicine, has led numerous studies on environmental lead contamination. In 2011, he found that the city’s older neighborhoods have high levels of lead in their soil, which can cause acute health problems, especially in children.
In a map outlining his findings, Mielke showed that inner-city neighborhoods have dangerously high levels of lead at some of the same spots where child care centers and community centers were erected after Hurricane Katrina. Soil at some of those spots contained concentrations of lead several times greater than allowed by federal guidelines for playgrounds.
That’s dangerous, according to the Centers for Disease Control and Prevention, because lead poisoning can cause learning disabilities, behavioral problems and even seizures, coma or death.
After the 2011 study, Mielke suggested a solution that would keep children from getting poisoned: covering the contaminated soil with a layer of water-permeable material and laying clean soil on top.
“We’re proposing a proactive strategy of primary prevention to protect children from lead poisoning and the health damage it can cause,” he said.
Now, Ribeiro wonders if her study can once again spark awareness about a very serious, and potentially deadly, issue.
Mockingbirds could be giving clues that city planners can use to prevent people from getting sick, she said.
“They could potentially play a role as a bioindicator,” Ribeiro said of her birds. “We could use other species to give us warnings about the quality of the environment we live in.”