Huron Municipal Pier. I spent much of the day here on November 22, and was once again blown away by the huge numbers of birds in the area. I've been to Huron in late fall and early winter scores of times over the years and know what to expect on a busy day, but never fail to be impressed. I wrote about some other observations from this trip RIGHT HERE. In that post, I focused on the numerous rare bird sightings that the trip produced. Here, I wish to focus on the hyper-abundant mergansers.
Note this male's wispy punk rock crest. This photo is from last February at a central Ohio reservoir. By then, the males have completely molted into resplendent breeding finery.
Mergus serrator), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/443
One of the few detailed studies of Red-breasted Merganser food sources was conducted in western Lake Erie. The results were published in 2008 ( 2008. Fall diets of Red-breasted Merganser (Mergus serrator) and Walleye (Sander vitreus) in Sandusky Bay and adjacent waters of western Lake Erie. American Midland Naturalist 159(1):147-161). This study showed that the mergansers primarily feed upon emerald shiners, gizzard shad, and the invasive nonnative round goby - this trio of fishes forms about 96% of their diet. Such knowledge should set fisherman at ease. The huge swarms of fish-eating ducks are NOT competing for prized walleye and yellow perch.
The Birds of North America Online, here is a map depicting the range of the Red-breasted Merganser. The breeding range is generally well to the north of Ohio. Our Lake Erie birds are all migrants, presumably from North America. But this duck also breeds extensively throughout northern latitudes of Russia, Scandinavia, Eurasia and elsewhere. No one has attempted to document the origins of the hordes of birds on Lake Erie. Which would not be easy.
ASIDE: I regularly share maps from Birds of North America Online (BNA) monographs, and harvest lots of useful information from these accounts. I've long had a subscription to BNA, and it is a wealth of information about birds. BNA is an inexpensive subscription service, and I would highly recommend it to those that want to advance their knowledge of birds beyond identification. Subscription information can be found RIGHT HERE.