In the past, researchers have found an array of pharmaceuticals, evident in the bodies of animals near sewage treatment plants. Researchers recently found the antidepressant Prozac may affect starlings (Sturnus vulgaris) with diluted concentrations of the drug in their systems. In a recent study, researchers discovered male starlings are less attracted to female birds that have concentrations of Prozac similar to those near sewage sites. The males sang less to females who were fed diluted concentrations of the antidepressant. Researchers say this could eventually make it hard for the birds to find a mate and breed.