Or nest boxes. Here, Jim Dolan holds a whopping big nest box that will soon be mounted to an appropriate tree along the stream. With luck, the mergansers will utilize it. Jim and Dan Justice began building and erecting nest boxes a few years back, and it appears the mergansers are taking to them. It's hard to get an exact handle on just how many breeding pairs there are, but the number seems to be rising.
Common Mergansers have an extensive breeding range across northern North America, and Eurasia. Little Beaver Creek in Columbiana County is at the extreme southern limits of their distribution. I feel pretty confident that this species wasn't nesting here until fairly recently. The region was covered fairly well in the first Ohio Breeding Bird Atlas, which ran from 1982-87. And there have been many sharp eyes on the creek since then, and I believe it was 2006 when the mergansers were first noted as possible nesters.
Thus, it appears we have a northern species expanding its range southward, at least slightly. We're seeing the same thing with breeding Blue-headed Vireos in Ohio, and some other northerners. It may be that the mergansers are merely reclaiming former nesting grounds, following a long-term recovery of the habitat. I don't think so, though, as the valley of Little Beaver Creek has long had the extensive mature forest buffering the stream that Common Mergansers require. Also, mergansers were found in appropriate nesting habitat along Conneaut Creek in extreme northeastern Ohio this year. It'll be interesting to see if the Conneaut birds remain to nest.
I'm grateful that we still have places like this. And I'm also greatly appreciative of people like Jim Dolan and Dan Justice, and many others like them, who work to protect and enhance Little Beaver Creek.