A mass of mergansers

Last Saturday, I made my umpteenth million trip to Lake Erie, that great water body that sits about two hours to my north. The lake is an irresistible draw, especially for one who is deeply into birds. Of the 420+ species that have been found in Ohio to date, well over 400 have occurred along Lake Erie.

Many of my excursions to our 4th largest Great Lake (by far the smallest, by water volume) have been in winter. Conditions can be brutal, but if you're willing to tough it out, the rewards are often great. I had no doubt that this day, January 6, would be a bit nippy. At one point on the drive up, near Lodi, the mercury registered - (minus!) 11 F!

By the time I arrived at Miller Park, in the shadow of the big power plant at Avon Lake, it had warmed to 5 F. Offsetting that warming trend were strong icy winds blasting across frozen Lake Erie from the north. Warm water outflows from the plant always keep a big patch of water from freezing, and winter birding is always interesting at this spot. Unfortunately, insofar as photography went, the copious puffs and tendrils of steam resulting from the clash between "warm" water and cold air precluded much in the way of shooting birds.

No matter, I spent two hours at the end of the pier watching the avian show. Lots of the true feathered tough guys gamboled about as if on a Floridian spring break. Herring gulls were abundant, having usurped the ring-billed gull's normal rank as commonest gull, as is always the case when true winter sets in. Lots of giant great black-backed gulls were about, looking nearly eaglesque from afar. A few ghostly arctic larids made the scene, a pair of glaucous gulls and an Iceland gull. There were scores of mergansers, both common and red-breasted, and many common goldeneyes. The latter is sometimes known as "whistler" due to the distinctive quavering sound produced by their wings in flight - a sound I was treated to on several occasions. As nearly always, a rogue American coot was toughing it out - world's toughest rail!

When it gets as cold as it's been, fantastic ice formations develop. This hunter's blind at Lorain Harbor is encased in frozen water, and large windrows of ice can be seen on Lake Erie in the backdrop.

In my last post, I wrote about birds' adaptability to cold. These Canada geese demonstrate winter hardiness. As soon as I walked onto the pier at Miller Park, I was struck by the spectacle of these ice-covered geese lolling about, resting and snoozing. It was 5 F and windy when I made this photo. The geese illustrate the supreme insulating effects of feathers.

After Avon Lake, it was back to the Jeep to warm up on the short drive west to Lorain, and its harbor. As an aside, about a year ago I got a 2017 Jeep Cherokee Trailhawk, which is proving to be a supreme winter vehicle. One of its bells among the whistles is a heated steering wheel. When those started showing up on cars, I considered it an excessive bauble. Not anymore. Greatest hand-warmer there is, after an extended immersion into polar temperatures.

Upon arrival to Lorain Harbor, I noticed a sizable elongate dark smudge on the ice, as seen in the above photograph. A polynya - packed with fowl! Aside II: "Polynya" is a Russian word that refers to an open water patch among sea ice. It's a great word that was brought into the birder lexicon when it was discovered in 1995 that spectacled eiders, whose whereabouts in winter was previously a mystery, were overwintering on polynyas in the Bering Sea. I see no reason why it can't be adapted to freshwater conditions.

Anyway, back to our Lake Erie polynya and its occupants. Mergansers! By the boatload! You can count up the individuals in this photo - I'm not! - and extrapolate, but there must have been a few thousand birds in this lead. The majority were red-breasted mergansers, although their ranks were spiced with a fair number of common mergansers. One thing is for sure - if you were a fish, you would NOT want to swim under this hole!

Here's a tight shot of the ever-shifting pack, using a gleaming white male common merganser as a centerpiece. Sharp-eyed birders will pick out some hen common mergs among the masses. The latter have brighter rufous heads, and a much cleaner demarcation between the white throat and rusty head than do the female red-breasted mergansers.

I spent quite some time watching this amazing frenzy of life in an otherwise frozen landscape. Birds were always coming and going - how do they take off and land in this crowd?! - and I bet the underwater view of the feeding birds would be incredible. There's a challenge for a serious aquatic videographer!

Red-breasted Merganser swarms on Lake Erie

Now that's a lot of birds! The waters at the interface of Lake Erie and the Huron River are darkened by thousands of Red-breasted Mergansers. Scores of gulls wheel overhead. Everyone is fish-seeking. Lake Erie is the most biologically rich of the five Great Lakes, and scenes like this bear out the aquatic bounty of Ohio's watery northern boundary.

A squadron of nine Red-breasted Mergansers rockets by the end of the 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.

A mixture of molting males and female Red-breasted Mergansers bunch together over a favorite fishery. The mouth of the Huron River has long been a major migratory hotspot for this species. Huge, and I mean massive, numbers of mergansers occur in central Lake Erie, especially between the islands just west of here and the Cleveland area to the east.

Rare would be the morsel that slides down a Red-breasted Merganser's gullet that is NOT a fish. These birds are piscivorous in the extreme. A sharply serrated bill helps seize and hold the slippery wriggling prey until the bird can manipulate the morsel so it goes down the hatch headfirst.

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.

If I were a small fish, say a shiner or shad, the last place I'd want to be is in the water under these birds. As soon as these mergansers settle on the water, they will begin diving for fish and they're very adept at catching them. The aforementioned fish species are the primary prey items in Lake Erie.

One would think that a species as abundant and glaringly obvious as is the Red-breasted Merganser would be well-studied and thoroughly understood. However, "Overall, the Red-breasted Merganser remains one of the least understood species of waterfowl in North America." That quote comes from the comprehensive Birds of North America monograph of the species (Craik, Shawn, John Pearce and Rodger D. Titman. 2015. Red-breasted Merganser (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
doi:10.2173/bna.443).

Scores of mergansers scuttle across the water whipping up whitecaps. On some unseen cue, hundreds or thousands of birds will suddenly swim-fly hundreds of feet to a new feeding locale. They undoubtedly are chasing the movements of large fish schools that they're feeding upon. This photograph shows but a sliver of a feeding flock that might have numbered 10,000 birds.

One of the few detailed studies of Red-breasted Merganser food sources was conducted in western Lake Erie. The results were published in 2008 (Bur, M. T., M. A. Stapanian, G. Bernhardt, and M. W. Turner. 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 numbers of mergansers on this part of Lake Erie can be stupefying at times. Estimates of 20,000 birds passing by one spot in an hour have been made, as have one-day tallies of up to 250,000 birds. Such numbers would be remarkable indeed, considering the total breeding population of Red-breasted Mergansers in Canada and Alaska is thought to be about 250,000 birds. It must be noted that the margin of error for shorebound observers attempting to estimate merganser numbers is large. There is just no way to know if one is recounting birds that are swirling about in circular patterns or regularly passing by the same locale over and again. However, having seen this phenomenon on numerous occasions from low-flying aircraft while conducting waterbird surveys, I can agree that the above estimates may not be far off the mark. Any way one slices it, there are many tens of thousands of mergansers staging on Lake Erie in late November and early December.

It's smack in the middle of this migratory spectacle - likely the WORLD'S most important staging area for Red-breasted Mergansers - that a corporation known as LEEDCO wants to place massive wind turbines. These, I believe, would be the first turbines located in the lake itself. Keep in mind that it isn't just mergansers that heavily use this part of Lake Erie. So do tens of thousands of Bonaparte's Gulls, huge numbers of Common Loons and Horned Grebes, blizzards of other waterfowl species, and scores of  other waterbirds. Turbines placed in bird-rich sites can cause great carnage, disrupt migratory patterns, and cause abandonment of habitat. The Black Swamp Bird Observatory has a nice summary on wind power projects in Ohio, including LEEDCO's "Icebreaker Project", RIGHT HERE.

Courtesy of 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.

Red-breasted Mergansers

Precious little time of late to cart the camera out and snap off photos. But a window opened up this afternoon, and I spent a few hours clicking the shutter about 1,500 times at one of my favorite subjects, waterfowl. There is an easily accessible open lead in otherwise frozen Alum Creek Reservoir, Delaware County, Ohio. It's just north of the Cheshire Road bridge, on the east side of the lake. The hole is jammed with waterfowl of many species, and if time permits I'll post some really cool stuff from this foray.

But for now, a female and male Red-breasted Merganser, two of many that were present.

A hen Red-breasted Merganser wrestles a small yellow perch into position for swallowing. A colloquial name for this duck is "sawbill", and that's because its mandibles are edged with sharp serrations, the better to grasp slippery prey.

Nearby was this gaudy drake. The boy mergansers were keenly interested in the girls, and many were engaged in their comical bowing courtship displays. I caught some of that action on pixels, and will try to put up some photos later. Anyway, what a cool duck this is!

Red-breasted Mergansers

Red-breasted Mergansers (mostly) on Lake Erie, east of Cleveland, November 2006. Lake Erie, especially the waters between the islands (South Bass, Kelleys, etc) and east to the Ashtabula area, is a major staging area for this species.

Our Ohio Birds listserv has hosted lots of discussion about this species, some of it from veteran lake-watchers who have a good grasp on waterbird movements on the lake. There is a general consensus that numbers have declined, but trying to determine by how much, or what the causes may be, is not easy.

I remember on many occasions seeing passing swarms of mergansers that were so massive and so dense that the flocks looked all the world like storm clouds scudding rapidly low over the water. Trying to estimate their numbers was practically an excercise in futility; certainly falling more into the "guesstimate" than estimate category. As many as 250,000 mergs have been claimed in one day in years past.

There are still a lot of birds on Lake Erie. I've been fortunate enough to have the opportunity to fly low over the lake in an airplane a number of times in recent weeks, specifically to estimate bird numbers and species. Aerial perspectives give observers a far more realistic picture of what's going on out on Lake Erie than onshore observers can hope for, in part because we can travel far beyond the reach of onshore optics, can cover much more ground, and can see many more birds simultaneously.

Estimating Red-breasted Merganser numbers on Lake Erie is still tough!

Red-breasted Mergansers are flighty critters; far more so than other waterfowl that we encounter on the lake. They are prone to frequent liftoffs and aerial sorties, and may do lots of circular wanderings, compounding the likelihood of double-counting. This is especially true when estimating from an onshore site, where it's possible many of the same birds will pass by in a relatively short window.

So, while merg numbers may be down from record highs of the 1980's, there are still lots of birds out there. Estimates from the last week or so from aerial surveys calculate well over 80,000, and these tallies are a lot more solid than prior estimates made from the ground. And it's almost certain that many birds are missed - it's impossible to find them all, even from an airplane.

It's premature to speculate as to exactly what may be causing the demise of Red-breasted Mergansers on Lake Erie, or even if they truly are declining.

There will be some interesting data on this issue emerging, and a good upcoming opportunity to learn more about the status of migratory waterbirds on Lake Erie. I'll report more on that later.