Heavy metal songs: Contaminated songbirds sing the wrong tunes
Understanding why mercury-contaminated songbirds can’t sing their songs could help scientists learn more about how human brains are damaged, too. Most birds known to be harmed by mercury are fish-eating seabirds or waterfowl. So Cristol set out to find out if mercury made birds have fewer chicks by studying three species of local birds that are closely connected to the aquatic food web: kingfishers, tree swallows and screech owls. Kingfishers nest in holes they dig into riverbanks, so Cristol and his students dug pits next to the nests, then carefully scooped their way in from the back to count eggs and young, and take blood and feather samples. For tree swallows and screech owls, they put up nest boxes. Other birds nested in the boxes, too, including bluebirds and wrens. “We sampled them just like everything else,” Cristol said.