7/13/25: The Hunt for the Red-breasted Merganser, part 1

Host: Logan Parker
Producer: Glen Mittelhauser

A noteworthy observation on Moosehead Lake sparks a determined effort to document one of Maine’s rarest breeding waterfowl.

Transcript

Many of the best experiences in field science are the result of pure happenstance and my efforts to document Red-breasted Mergansers breeding in Maine were no exception. 

It was late June in the final year of the Maine Bird Atlas. Having been assigned to survey an area encompassing a large portion of Moosehead Lake’s Northwest Cove, I decided I would conduct a quick paddle of the shoreline to document birds breeding on or near the lake. Reaching the launch site at the end of a long wood’s road, I set out having made the rare decision not to bring my camera, opting instead to rely on my binoculars alone– a decision I would shortly come to regret.

Rounding into the cove from the south, I set out along the wooded shore. A dense hedge of tall spruce, fir, pine, and mixed hardwoods flanked the shoreline while large boulders rested on the water’s edge below, lapped by gentle waves. Songbirds of all kinds sang from the lakeside trees, each laying claim to their own mossy alcove or coniferous spire. A vibrant Northern Parula chided from limbs outstretched above the water and hopped from branch to branch, its bill brimming with insects. A pair of Broad-winged Hawks wheeled together above the canopy giving their loud, high calls – the male’s voice slightly higher than that of his female partner. The breeding season was in full swing and the riparian woodlands brimmed with activity. A choir of thrushes, vireos, kinglets, sparrows, wrens, warblers, and chickadees sang in the lush breeding grounds in an overlapping chorus. I paddled onward.

The shoreline changed as I moved northward from a tight, continuous forest hedge to a wavering shore broken by large piers of stone and shallow pools fenced by breakwaters of submerged boulders. A Belted Kingfisher moved from one snag to the next as I approached. The lake waters themselves had been empty up to this point, save only for a passing Double-crested Cormorant winging its way over the surface with a flurry of flaps. 

Suddenly, I caught sight of movement ahead and watched as two forms glided out from cover towards open water. They were shaggy crested ducks and thin red bills. Common Mergansers? To my surprise, no. This was instead a pair of Red-breasted Mergansers, a species I have encountered many times along the Maine coast in winter, but had never observed one during the summer and on freshwater. I thought of my camera sitting on the backseat of my car at the launch site and my heart sank. Although I knew this was at least unusual, I was not certain of exactly how notable this observation actually was. I endeavored to document the birds as best I could with thorough notes and, if I could, get some photographs with the only camera I had on my person: my cell phone. Pulling it from my pocket, I started taking shots and recording video of the birds, mere specks in the small lens. The pair slowly bobbed further from shore before taking flight. A review of the recordings brought some relief as I had gathered some verifiable evidence. 

Although cell service had been spotty, I was able to get a message out to a few trusted authorities. While I waited for their responses, I examined the species’ breeding range map in my field guide. The southernmost extent of the bird’s defined breeding range fell north of the Maine border wrapped tight around the St. Lawrence. I had seen both a male and female traveling closely together in the height of the breeding season. Could these birds be breeding here on Moosehead? It certainly seemed possible. 

I would learn from Louis that a lone male M. serrator had been observed on Moosehead by other birders near Greenville, just 25 miles to the south. There were past records of these birds on the lake too, but were either insufficiently documented, gathered too early or late in the season to be considered breeding birds, or else determined to be cases of mistaken identity upon further examination. While Red-breasted Mergansers were suspected of breeding in the state, they had yet to be satisfactorily documented. My curiosity was piqued and I determined that, should time allow, I would return to Northwest Cove and attempt to seek out the birds again. 

That opportunity would not come until nearly a month later. Although I thought the merganser pair often, other obligations would keep me afield in remote portions of the St. John River Valley. Nonetheless, I was eager to return and my observations along the northern river branches only increased my desire to resume the search. By late July, many birds are wrapping up their breeding seasons. Although a handful of late or double-brooding species will rear young into late summer, the majority birds have completed their breeding obligations. While atlasing along the St. John, however, I noted that the Common Mergansers there were late breeders and many hens still had very young ducklings under their carry. I spotted one hen roosting across the river on a boulder and a pile of downy young birds on a lower stone beside her. I speculated that Red-breasted Mergansers could be late breeders also, a theory I confirmed with some research into the species’ life history. I posed the idea to the Atlas’ coordinator (MNHO’s own Glen Mittelhauser) who enthusiastically supported the plan to return to conduct some follow up efforts as soon as conditions permitted.