Pigeons doing canary duty to detect lead levels in NYC neighborhoods

UC Davis assistant professor Rebecca Calisi conducted a study while at Columbia University in New York, along with undergraduate Fayme Cai. They found that just as with children, pigeon blood lead levels rose in the summer. If you found a neighborhood where the local pigeons had high lead levels, the same went for the kids in the area. Since pigeons aren’t migratory and rarely stray far from where they live, the correlation eliminates location as an independent variable.

“Pigeons breathe the same air, walk the same sidewalks, and often eat the same food as we do,” said Calisi. “What if we could use them to monitor possible dangers to our health in the environment, like lead pollution?”

There is no safe level of lead in humans, and it’s especially dangerous for children. Problems with nervous system functions as well as learning and developmental disabilities are all linked to high lead levels. The pigeons can’t tell anyone where they get exposed, but it’s not likely from eating lead-based paint. Rather, the birds probably get it from the gravel on the streets that they swallow to aid with digestion. Children in the same neighborhoods may track the gravel into their homes. Passing cars and airplanes are also good candidates as sources of airborne lead.

Coal miners used to carry canaries in cages into coal mines to detect methane and carbon monoxide — the canaries would die before the levels were hazardous to humans. Pigeons in city neighborhoods could serve a similar sentinel duty.

“This is a powerful example of how we can use pigeons to monitor the location and prevalence of pollutants,” said Calisi added. “We can use these ‘rats with wings’ — which are anything but — to monitor dangers to human health.”

In further testing, Calisi is going to determine whether pigeon blood tests indicate levels of heavy metals, pesticides, and fire retardants in cities in California. Pigeons are already used in air quality monitoring to detect pollution in some European cities. According to Calisi, her study is the first that correlated pigeon blood levels with children.