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Poisoning pigeons in the park: Using urban pigeons to monitor lead levels

Stop the presses: Somebody found a use for the pigeons in New York City. A new study of pigeons in the City shows that lead levels in the pigeons track closely with lead levels in children living in the same neighborhoods.

“Pigeons breathe the same air, walk the same sidewalks, and often eat the same food as we do. What if we could use them to monitor possible dangers to our health in the environment, like lead pollution?” asked Rebecca Calisi, assistant professor at UC Davis, who conducted the study with undergraduate student Fayme Cai while at Columbia. The report is published in the latest issue of Chemosphere.

They team found that the pigeons’ blood lead levels rose in summer, in just the same way as in children. Zip codes with high lead levels in pigeons also had some of the highest rates of raised levels of lead in resident children.

Why? Urban pigeons are particularly suitable for this work because they don’t fly far, typically spending their lives within an area of a few blocks, said Calisi.

The sources of urban lead pollution aren’t all clear. Leaded paint can still be found in old buildings, but pigeons don’t spend much time indoors. Road and air traffic are likely sources of particulate and airborne lead, and pigeons do pick up roadside gravel to help digest their food. It makes sense, then, that children living near the same sources of lead pollution could also be exposed, even bringing lead into their households by regular foot traffic.

While pigeons have been used to monitor various types of pollution in some European cities, to her knowledge no one has previously correlated lead exposure in birds with exposure rates in children, Calisi said.

Calisi is expanding the project, heading West to study other pollutants such as other heavy metals, pesticides and fire retardants, in California cities.

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

Lead is dangerous to humans of all ages, but particularly so to children. Lead interferes with the function and development of the nervous system and is strongly linked to both learning and developmental disabilities at sufficiently high concentrations. Even more problematic, there’s no known lower threshold at which lead exposure can be deemed “safe.”


One of the more interesting theories about lead is the potential link between average childhood lead levels and the number of violent crimes committed per capita in the United States. From the 1930s to the early 1970s, violent crime in America steadily increased. Thereafter, violent crime levels began to drop. While the exact shape of the curve depends on whether you examine all violent crime (as above) or only use the murder rate, there’s a startling correlation between crime levels and the amount of lead detected in childhood populations.

Not bad for a bird so infamous, Tom Lehrer once wrote a song about the joys of feeding pigeons peanuts coated in cyanide. Then again, who hasn’t whiled away a pleasant…

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