We came across this interesting article in the NY Times. Here is a quick summary.
On Monday, the journal Chemosphere published a study that found Manhattan neighborhoods where many children presented elevated blood lead levels had pigeons with elevated lead as well. These study results suggest that scientists may be able to use the birds to predict lead contamination in their surrounding environment. Rebecca Calisi, who is the primary author of the study, analyzed data of about 825 pigeons from different neighborhoods around New York. The research took place from 2010 to 2015. Dr. Calisi found that elevated lead levels in pigeons from Greenwich Village and SoHo that positively correlated with elevated lead levels in children in those same areas. Dr. Calisi also said pigeons might be ideal animals for making comparisons with human health because they live in close proximity to humans and they eat much of the same food.
Read more: http://www.nytimes.com/2016/07/19/nyregion/pigeons-may-predict-lead-contamination-study-finds.html?_r=0