Why might Maine lose two species of songbirds?

Maine may lose two tidal marsh songbird species in the next few decades. Salt marsh sparrows face extinction, while Acadian Nelson’s sparrows are threatened with extirpation — localized eradication with the possibility of survival elsewhere. Their populations along the Eastern Seaboard have been declining as sea level rise destroys their habitats and, according to a new University of Maine-led study, mercury exposure inhibits their reproduction. In the final episode of Season 5 of “The Maine Question,” Kate Ruskin, a lecturer in ecology and environmental science at UMaine who spearheaded the recent mercury exposure study, and Brian Olsen, who is now an associate provost at the university, discuss the challenges these songbirds face, and what can be done to prevent their loss. They also describe their fieldwork and the benefits for students who participate in it.