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The hatch is underway. 2023 was a miserable year for black flies. But loon pairs that laid eggs in mid-May and kept incubating them despite fly harassment are getting their reward this week. Granted, this reward comes in the form of one or two tiny puffballs that need continual warming, must be protected from a host of predators from above and below, require gentle handling, and can only consume tiny food items offered patiently and gingerly. But such is the reward.

We are especially excited about the two chicks hatched in the past few days on Little Bearskin Lake in the Wisconsin Study Area. Why? Two reasons. First, with an estimated age of 34 years, the mother of these chicks is our oldest study animal. Second, our team happened to capture this female two years ago and discover that she was injured and ailing after getting entangled in fishing line. Our rescue of this ancient female allowed her to rear a chick with her mate in that year and another last year. If she is able to raise the two chicks just hatched with the same male, she will — in our view — have produced four “bonus chicks” above what would have been possible without her disentanglement. The ability to witness several of our study animals resume breeding after cheating death with our help is one of the joys of our work.

“Two chicks on Little Bearskin?”, you say. “I just see one in the photo.” Indeed, Linda Grenzer captured this picture of the single chick that just hatched on Crystal Lake near Tomahawk. I like the way the chick seems baffled at the distance between itself and its nearby parent. (“Why have you left me here?”)

Do not despair if your loons are still on eggs or not nesting. Little Bearskin, Crystal, and a handful of other pairs are among the intrepid few in Wisconsin that survived the barrage of flies undaunted and will hatch this week.

While most of our Wisconsin loon pairs were forced to abandon their first nesting attempts, Minnesota loons in Crow Wing and Cass Counties tended to respond to fly harassment by postponing their first breeding efforts. Hence, the bulk of our Minnesota pairs began incubating during the last few days of May or first week of June. However, a small number of stalwart pairs in Minnesota laid in mid- to late-May and hung in there during the fly weeks. Those pairs — which include Kimball-East, Kimball-West, Little Star, Big Trout-West, Ossie-Boozer’s, and Ossie-Timberlane — should hatch in the next week to ten days, if all goes well.

We are still hopeful for a solid breeding year for both study areas. Fortunately, loons follow the same philosophy that humans do when it comes to setbacks. When you get punched in the mouth, you don’t stay down. You get back up and see to your business.

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The saying “success breeds success” was not coined with loons in mind. But we humans know from experience that an initial success can increase the likelihood of a second one. Indeed, I relearn the value of accumulated experience each spring during the period when I train field observers. With no background in the technique, new observers are utterly astounded when we locate the first nest of the year. After five more nest discoveries, though, they begin to develop a “search image” for nests. It is a thrill to see them learn quickly over a period of a few days to the point where they begin to point out loon nests to me!

Loons are not complete strangers to the benefits of learning. Males often place nests in poor locations when they first attempt to nest on new territories. After a bit of blundering about and some poor decisions, males typically find a nesting spot that results in a successful hatch. Afterwards, they reuse that good spot again and again, enjoying much greater success than during their first attempts. Thus, nesting success following an initial period of failure leads to further nesting success.

The impact of a loon pair’s nesting success on territory defense is another matter. The loon territorial system differs in a crucial respect from those described in other species. In many birds, most notably colonial seabirds, young adults prospect for good breeding sites by looking to see where other adults have produced chicks. When these young seabirds settle to breed, their settlement has little or no negative impact on adults already breeding at the huge colony. Not so in loons. Young adult loons prospecting for territories use chicks they spot on a specific territory as a badge indicating quality of that territory alone. Young prospectors must battle the current residents for ownership of such high-quality territories. That is, chicks seen in one year induce prospectors to return the next seeking to evict the owner of their sex and claim the territory for themselves. So adults that produce chicks experience the joy of parenthood…..but have also placed their future territory ownership in jeopardy.

The mixed blessing brought about by successful chick-rearing is nowhere more obvious than on the Pelican Lake-Mousseau Bay territory in the Minnesota Study Area. Online observers watching via the live nest cam were treated to a lengthy battle between two adult loons a few days ago. While the battle was shocking in its brutality, it was not surprising. We have long known that the successful rearing of chicks leads to a surge in interest in the territory and, hence, the likelihood of territory loss by one or both breeders. After raising two strapping chicks last summer, the male and female of Mousseau Bay must have braced themselves for a litany of territorial intruders and challenges. Indeed, the banded 2022 male apparently lost his position this spring; last year’s marked female is now paired with an unmarked male.

And yet there is hope. Yesterday, the old female laid an egg. She and her new mate both seem anxious to sit on it. If they can weather the blitz of black flies currently dogging their incubation efforts, they stand a good chance of repeating last year’s success.

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Although it was June and Saturday, Upper Whitefish had a post-Memorial Day hangover. June 4th, 2022 was one of those rare, almost unnaturally calm days on the huge lake. It was the kind of day when canoes, kayaks, and paddleboats — which pass most of their days overturned and collecting spiders in sheds — set out across the big water with sudden purpose.

I was supposed to be training students for field data collection. Lauren, a recent arrival to Minnesota, was in the midst of learning how to spot loons, ID them from their colored leg bands, find their nests, and record data related to breeding ecology and behavior. When Lauren announced that she was uncomfortable paddling a canoe on Whitefish and wished to skip the training session, I initially glanced out at the flat lake in puzzlement. But we had hit windy and wavy conditions on Whitefish two days before, so I quickly deduced that she was uneasy about venturing out on the same body of water again so soon. “Okay”, I said, “maybe you can find a put-in for the Upper Whitefish-Steamboat loon pair.” We looked at a road map, planned Lauren’s route, and went our separate ways.

The loss of my paddling partner — and most of a day of training — was a disappointment. On the other hand, I love my occasional moments of solitude on Northwoods lakes. Setting out alone from the huge boat landing on Lower Hay Lake (which is attached to Whitefish), I visited the four loon territories on Lower Hay, untroubled by wind. Two and half hours later, I pushed through the channel that leads to Upper Whitefish. Shortly thereafter I spotted the Upper Whitefish-Steamboat pair and their platform nest. Lauren was smiling and waving from a dock not far from the platform. She had met a friendly loon-lover who invited us to launch our canoes from his dock whenever needed. (Access points for loon territories can be hard to come by; she had spent her time well!) A jovial soul, our host added wryly, “You’re lucky; you came out on one of the three calm days we get each year on this lake!”

Leaving Lauren ashore again, I set out to check more loon pairs on the main lake. At the Little Island territory, I ran across a nest with two eggs in a patch of cattails. It was attended by an unmarked loon pair.

Next I decided to circumnavigate Big Island. I found myself increasingly enchanted by the tranquility of the scene, which was undiminished by the vast expanse of water before me. I became so giddy at the spectacle that I almost stuck out my hand to high-five two complete strangers in a passing canoe. Loonwise, however, Big Island was unimpressive; I found only the usual tame pair at the southeastern end (one marked) near a recently failed nest. But I stumbled upon a real treat as I finished circling the island: three Bonaparte’s Gulls jostling for position on a narrow sandy spit.

I smiled to see that, like me, these three diminutive migrants were taking advantage of the conditions. In their case, a few invertebrates provided snacks in the shallow, gently lapping water. Apparently it is widely known that when you venture out onto the Whitefish Chain on one of the three calm days of the year, you must make the most of it.

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Linda began to worry on April 18th when “Lucy” — the female from Muskellunge Lake whom we banded last year — showed up in a patch of open water with two other loons from the neighborhood. Male loons usually arrive a few days before females. Clune, the most famous loon in our study area, resident on Muskellunge since 2008, and Lucy’s mate, should have been back. Linda’s careful records show that Clune has appeared on Muskellunge before his mate in every year during the past 10 years except 2020, when his mate showed up two days before him.

It’s funny how, even as a scientist, I became attached to Clune. I remember encountering him back on Manson Lake in 1998. As his parents fished together in one cove near the boat landing, 4-week-old Clune and his sister dove together in a nearby cove. I tried to stay in contact with adults and chicks without approaching either pair too closely, but the chicks kept surfacing near my canoe and on the opposite side from their parents. On each such occasion, I paddled rapidly away and towards the lake’s center to restore the parent-offspring sightline. But neither parents nor chicks panicked, as I did, when my canoe split them. My canoe and I inspired the same degree of alarm as boulders, piers, and patches of vegetation.

Clune was precocious. He first appeared back in the study area as a two-year-old intruder on Hancock Lake. He wandered around for the next few years, as nonterritorial adults do. In 2003, he settled on Deer Lake, only 3 miles from Manson, where he had been raised. He and his mate produced chicks in 2003, 2004, and 2005 on Deer. Two of his sons from this period have followed in his illustrious webbed footsteps: one is the long-time breeder on tiny Virgin Lake; the other has cranked out offspring since 2014 as the territorial male on Squash Lake-Southeast.

Although we did not know it at the time, Clune’s breeding success on Deer was merely a prelude. Indeed, Clune and his second mate hit a slump on Deer from 2006 to 2008, failing to hatch a single egg. And so, as loons often do in the prime of life, Clune turned his attention to nearby alternatives. Muskellunge Lake was a chick-producer during the three years of Clune’s slump. Thus, in mid-June of 2008, Clune intruded into Muskellunge, battled the male territory owner, drove him off the lake, and settled on Muskellunge with the resident female.

Yet Clune seemed ambivalent about leaving Deer, where he had produced several chicks, and occupying his valuable new territory on Muskellunge. He faced an embarrassment of riches, it seemed. For three years, Clune and his mate bounced between Deer and Muskellunge. And Clune’s breeding slump stretched to five years.

At long last in 2011, Clune and a new female (“Honey”, as Linda came to call her) reared two chicks on Muskellunge. It was no fluke. The chicks of 2011 began one of the most impressive runs of breeding success we have ever seen in northern Wisconsin. Between 2011 and 2021, Clune and Honey hatched chicks in every single year and raised 13 chicks to adulthood. (Clune added a 14th chick in 2022 with a new mate, Lucy.)

What set Clune and Honey apart from other pairs was their dogged determination as incubators. 2011, 2014, 2017, 2019, and 2020 were years during which 27% to 90% of all loon pairs in northern Wisconsin abandoned their May nests owing to severe black fly infestations. Clune and Honey sat tight throughout these dreadful years, tolerating hours of motionless incubation while flies sucked their blood at will. They did not abandon a single nest. Consider this feat for a moment. Both pair members must be committed to warm the eggs for several hours at a stretch in order for a nesting attempt to succeed. While loon pairs throughout the study area abandoned their nests and hatched few chicks for a decade, Clune and Honey thrived.

Despite his sterling breeding record, it is Clune’s affability that I will miss the most. He seemed to sense that humans in canoes and kayaks meant him no harm. Perhaps he even got to know Linda and me, since he had seen us so often throughout his life. It certainly seemed so at night when he hardly budged as we gently threw a net beneath him each year, lifted him out of the water, weighed him, and replaced his worn bands.

There is a new male on Muskellunge this year. (See Linda’s featured photo of him yodeling, above.) He is “Yellow over Copper, Red-stripe over Silver”, a 12-year-old hatched on Prairie Lake who has lived and attempted to breed on nearby Halfmoon and Clear Lakes for the past three years. Like all males on new territories, he will probably struggle on Muskellunge to find a nest site where he and his new mate can hatch eggs. Maybe Yellow over Copper will beat the odds, take advantage of the plentiful breeding habitat on the lake, and raise a chick or two in his first year. I am keeping my fingers crossed for him. He is a fairly tame loon and a vigorous defender of his new territory. I knew his parents for many years on Prairie and have a good feeling about him. But he is not Clune.

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It is easy to forget that research on the loons of Crow Wing County, Minnesota has been underway for over a decade. To be sure, this work has been spotty. From 2011 to 2014, Kevin Kenow and his USGS team placed geotags on a few dozen adults on four medium-sized lakes in the county. From 2015 through 2017, he shifted his efforts to the Whitefish Chain, where he captured 68 individuals, including 36 territorial adults.

Kevin’s goal was to determine migration and wintering routes of Minnesota loons, which he did after recovering many of the geotags placed on loons’ legs. Although his study was short-term, Kevin’s loons lived on. Each summer and fall they nested and reared young, foraged to build up their reserves for migration, staged on the Great Lakes, and made long overland flights to the Gulf of Mexico. Each spring they molted their feathers and made return trips back to the Whitefish Chain to restart the cycle.

When our Minnesota Loon Project began in 2021, we relocated many of the loons Kevin had banded 4 to 6 years before. We were quite thorough — obsessive, even — in our efforts to do so. At the time I regarded the USGS banding effort as fortunate for us, since it gave us a head start in our efforts to mark all territorial pairs on the Chain.

But Kevin’s marked loons have not merely reduced our loon marking workload. Kevin’s birds are charter members of the Minnesota Loon Project. The survival of these inaugural adults since the years Kevin’s team marked them provides our first multi-year snapshot of adult loon survival in Crow Wing County.

The data provide an unconventional snapshot. When one conducts a mark-recapture study, one normally searches diligently for all marked individuals during the years immediately after marking. This strategy produces data on annual return rate, which provides an estimate of annual survival. But we lack data on return rates from 2018, 2019, and 2020. So we must do the best we can to extract information from Kevin’s birds despite multiple years with missing data.

Fortunately, this is not rocket science. If “r” is the annual rate of return, then r2 is the probability of being on territory two years after banding, r3 is the probability of still being present three years later, and so on. Recognizing this, we can easily project how many of the 36 territorial adults that Kevin banded in 2015, 2016, and 2017 should have still been on territory in 2021. If annual rate of return were 90%, we would have expected to see 20.5 of Kevin’s loons in 2021. At 85%, the expectation is 15.1. If the annual rate of return were 80%, then we should have seen 11.0 loons. In fact, our exhaustive search turned up 13 of Kevin’s loons. So this places our rough estimate of annual loon survival for the Whitefish Chain at 82.5%.

To my knowledge, ours is is the first long-term estimate of adult loon survival from Minnesota based on a marked population. This is rather shocking; loons are well studied in the U.S., have been marked in at least ten states….and are the state bird, for goodness sake! In any event, this preliminary estimate gives us a ballpark figure for adult survival that we can compare with more robust estimates from other states.

A figure of 82.5% for Minnesota survival is lower than we would like. This long-term number based on Kevin’s birds, though, is slightly higher than the separate return rate of 51 Crow Wing County adults we banded in 2021 and looked hard for in 2022: 80%. For comparison, we have robust estimates of survival from a study done 15 years ago that included data from New England (88%; data from 1994-2001) and Wisconsin (87%; data from 1991-2001). We can also compare with longer-term survival rates from our well-known Wisconsin Study Area, which, again, were 86 to 87% for both males and females. In short, early data from the Minnesota Study Area indicate a percentage of adult survival in the low 80s, which is below the rates in the upper 80s we have grown accustomed to seeing in Wisconsin and New England.

The data from Minnesota so far only provide a glimmer about the loon population in Crow Wing County. However, these low survival estimates do bring to mind a worrisome downward trend in loon numbers for the region that can be seen in the 2021 Minnesota Loon Monitoring Report. But, really, it is early days. We need more data. Furthermore, the status of a loon population is not dependent upon adult survival alone. Low adult survival can be offset by a high reproductive rate. So we will have to spend at least two more years tracking return rates of marked loons and measuring breeding success before we can pull them together into a model that will tell us (preliminarily) how Crow Wing loons are doing. Still, if I am being honest, I wish the survival numbers were a bit higher.

Thanks to Katy Dahl, who photographed the Cross Lake-Arrowhead Point loon pair after we banded them in 2021. The male in the foreground with his bands out of water was spotted a few days ago just north of Minneapolis.

If, like us, you are concerned about the persistence of loons in Minnesota, consider a donation to support our field efforts. We run a lean program. Funds donated to the Loon Project do not pay overhead, administrative costs, or salaries for staff or senior personnel. They pay only field costs like: 1) stipends to keep student field workers alive, 2) travel costs to, from, and within our study areas, and 3) supply costs such as for colored leg bands and canoe paddles. Thanks!

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A week or so ago I gave a talk to the Northeast Loon Study Working Group. Inauspiciously-named and -initialled, NELSWG comprises loon conservationists from New England, the Upper Midwest, and a smattering of other regions within the loon’s breeding range. At present, NELSWG is the only group that attempts to pull together data on loon populations and brainstorm strategies for protecting the species. During my talk I shared our data showing that masses of adult loons and chicks decline as water clarity declines. I then updated the group on my analysis of male and female traits that lead to breeding success of pairs.

Impact of male (blue) or female (red) pair member on a pair’s hatching success. Both males and females are a drag on hatching success in their initial year on a territory. Females have a slight positive impact thereafter. Male experience on a territory continues to improve hatching success even after 10 years.

To remind you, a male’s knowledge of the territory makes a huge impact on the breeding success of a pair. Since males choose the nest location, males are a drag on nesting success in their first few years on a territory because they place the nest in lots of dangerous places. (Note the low blue bars for years 0 to 3 above.) On the other hand, males that have been on a territory for seven or more years are a boon to pair nesting success, because they have learned the safest spots to place nests. (Note the blue bars from 8 to 20 years on territory.) Females have an impact too. In their first year on a territory, females cause low hatching success for their pair. In later years, female territory experience boosts hatching success slightly.

It is almost more interesting to see the factors that do not affect breeding success. A male’s age does not affect his pair’s ability to fledge chicks at all. At first glance, this seems confusing. How can the male’s age have no positive impact on breeding success of a pair, when a male’s breeding experience on a territory is hugely important? The answer relates to cause. It is true that old males tend to have very high breeding success, but this is not because of their age but because, in most cases, they have been on a territory for many years. We know that age itself is not causing high breeding success because old males that nest on new territories have no greater breeding success than young males on new territories. It is familiarity with the territory and not age that is the salient factor.

Female age has only a weak negative impact on breeding success. In other words, older females lose chicks at a slightly higher rate than young females. This pattern is a bit difficult to make sense of, because the effect is so steady and gradual. Why would a 15-year-old female lose chicks at a higher rate than a 10-year-old female parent? Both females are in the prime of life, in the loon sense.

Effect of female age on a pair’s fledging success. Females cause a gradual decline in fledging success as they grow older.

To the listeners at NELSWG, though, the pattern that was most remarkable was the lack of a strong effect of mate familiarity. While pairs that know each other nest a few days earlier than pairs that are in their first year together, the pattern is weak (see below). Furthermore, the slightly earlier hatch date among pairs that know each other does not translate into a detectable advantage in overall breeding success. In short, pairs benefit only slightly from knowing their mate well.

Effect of pair-bond duration on hatching date. Pairs in their first year together nest later, on average, than pairs that have been together for at least one year.

How can this be? How can a male and female remain together year after year, raise young cooperatively — and still not benefit from this lengthy association? That was the question asked by Lee Attix at the NELSWG meeting. I don’t have a good answer for Lee. As a male in a 38-year relationship who has raised young cooperatively, I am well aware of the benefits that a long-term partnership can bring in the human species. But loons are different.

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I should have known all along. I should have known last May, when the ancient outboard motor we had just bought to cover the Whitefish Chain spewed a foul rainbow sheen onto the water’s surface and belched a caustic purple cloud that momentarily blinded us. I should have known as I filled huge tanks of gasoline at the Holiday convenience store in Crosslake, hefted them down to the dock, and hooked them up to the belching motor. I should have balked at the absurdity of using a filthy, fossil-fuel-guzzling outboard to study an animal that requires clean air and water.

Instead, I shrugged. “This is how people get around in the Northwoods”, I thought. “This is inevitable. This is the environmental cost of studying loons on big lakes.”

In my own defense, my understanding of proper boating practices became ingrained during my childhood. Back then, when we needed to provision our cottage on an island on 40-mile-long Lake Temagami in central Ontario, we took our little 2-stroke outboard over to the Ojibway Store on Devil’s Island. I still recall taking in the pleasing aroma of balsam fir mingled with mixed gasoline as we listened to the soft lapping of waves against the store’s dock. At the time, my major concern was whether Mom would treat us to Burnt Almond bars when she had finished ordering our groceries. Gasoline was just an innocuous part of the landscape we inhabited.

Indeed, to folks of my generation and generations adjacent, the angry whine of an outboard motor, the slap of a stiff wind in our faces, and the sight of parting, churning waters behind us seem inextricably linked to the pungent smell of gasoline.

But it need not be so. There is a growing market for electric outboards (and inboards) that can replace gasoline motors smoothly and are far cleaner (of course), quieter, and — according to what experts say — very reliable and low-maintenance. I have been researching this.

Why have I experienced this sudden desire to go electric on the water? Two reasons. First, the last two Wisconsin field teams and I faced an absolute nightmare every time we tried to start up our vintage 9-horsepower Evinrude. I did not collect data on our efforts, but I believe we averaged 43 almost-shoulder-dislocating tugs of the starter cord per lake to get that dirty old 2-stroke started. I have had it! (I believe Sarah ’22, Molly, Claudia, Chris, Tia, Bailee, and Sarah ’21 will applaud this move.)

Second, I can no longer deny the obvious. The relentless march of climate change has begun to hurt loons in the Upper Midwest. We can see it in the increase in the May black fly population, which forces loon pairs to suffer horribly as they to incubate their eggs, often to the point of abandonment. And it is even more evident in the sharp decline in July water clarity during the past quarter century (see below) — a decline that impairs loon parents’ ability to find food to feed their chicks. Both increased black flies and decreased water clarity, we now know, come about in large part because today’s warmer, rainier summers produce more flowing water that: 1) supports increased black fly reproduction and 2) washes more matter into lakes that reduces clarity.

So I have finally figured something out that I should have guessed before. Climate change is hurting loon populations in the Upper Midwest in multiple, measurable ways. Cutting back on fossil fuel usage where I can will help slow this damaging pattern. And that is a step in the right direction.

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The past month and a half have been a roller coaster ride, though mostly downwards. Six weeks ago I learned that major funding for my field work in Minnesota had dried up. I cursed my luck. I scratched my head. A thousand “what ifs” passed through my brain.

But looking back was pointless. In time, my mind began to turn to one cheerful and unassailable fact. Loon Project field teams in 2021 and 2022 had given their all to expand our database into a new state where, initially, we knew almost no one. As we began to meet the warm, supportive, loon-loving folks of Minnesota, we gained momentum. The National Loon Center provided tons of support, financial and logistical. New friends shared boats, gave us access to private lakes, towed our capture boat from lake to lake in the middle of the night, or simply drove us around in their own boats during capture to help us find and mark breeding loon pairs. Kevin Kenow and his USGS colleagues spent six long nights in 2022 capturing loons to swell our study population. When the dust settled in early August of last year, we were well over halfway to our goal of establishing a Minnesota Study Area on par with our traditional study area in Wisconsin.

That we have not been diverted from that path is a tribute to our great pool of friends and supporters in Wisconsin, Minnesota, and across the U.S. One day a few weeks ago was a first turning point. An anonymous friend from Wisconsin pledged $7,000 “to support the Minnesota part of the Loon Project”. I was touched that someone in Wisconsin trusted me with this gift, and moreover, dedicated it not to the loons of their own state but to those of an adjacent one. *

Just yesterday, another group of donors from Minnesota helped us reach another turning point. Roger and Phyllis Sherman, Don Salisbury, and Gwen Myers have together contributed $21,000 to the Minnesota Loon Project to establish the Judith W. McIntyre Fund to support our work in the state.

It is a great honor to feel that I am building upon Dr. McIntyre’s seminal work on loons, which took place in Minnesota, Saskatchewan, and Upstate New York. Judy had a gift. She did robust, impactful science that taught us a great deal about loons. At the same time, she was able to convey her passion for loons and loon conservation in a charming, down-to-earth manner that reached the public. I have a dog-eared copy of her classic book, “The Common Loon: Spirit of Northern Lakes” on my shelf to which I often refer. When I think back to my interactions with Judy, though, what I remember most vividly is the warmth and humility with which she welcomed me to the fellowship of loon biologists back in the mid-1990s. She viewed the study of loons as a calling to which all could aspire — even the young whippersnapper that I then was.

The new Judith W. McIntyre Fund is a timely and exciting development. This gift adds to the dozens from other supporters of the Loon Project from Alaska to Colorado to Maine who have stepped up to donate during our time of greatest need. And I cannot forget other folks who have provided the Loon Project team with lodging in Wisconsin (especially Skip and Ruby, Mary, and Linda and Kevin) and Minnesota. Friends and supporters have truly kept the Loon Project afloat in recent years. Gifts earmarked for Minnesota have now brought us right back to where we were before the loss of funding six weeks ago. In other words, thanks to all of you, our goal of producing a robust population model for loons in north-central Minnesota is back on the horizon.

Since I view many events in my life through the prism of my study animal, I cannot help but recall at this moment the plight of the former male loon on Jersey City Flowage, near Tomahawk, Wisconsin. (See Linda Grenzer’s photo of him, above.) Banded as a chick on Swamp Lake (9 miles away) in 1995, “Red/Red, Red/Silver” had easy-to-read bands and a relaxed disposition to match. During each spring for over a decade, I looked forward to seeing his bright color bands under the surface as he permitted us to approach him closely for identification. But he was suddenly at death’s door in June of 2014 after swallowing two lead sinkers attached to a fishing line. If not for the quick and professional work of the Raptor Education Group, he would have been doomed to a slow and painful demise. The REGI folks removed the sinkers, patched up his lacerated tongue, fed him all of the suckers he could swallow, and quickly got him back in the water. Defying the odds, R/R,R/S recovered his lost body mass, migrated southwards in the fall of 2014, and returned to breed the following April, as laidback as ever. He must have felt then as I do now.

I know what you are thinking: another feel-good story of overcoming adversity that features loon/human parallels! Now that we are back in business in Minnesota, perhaps I will plague you less often with such tedious anecdotes. But things have been going pretty well lately. So I can’t make any promises.

* As I noted in an earlier post, research in our traditional Wisconsin Study Area will proceed as before. That is, we will continue to build the Minnesota Study Area without compromising our productive long-term study of loons in Wisconsin.

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One often hears that clear water is a benefit to loons — if not an outright requirement. The entry for the “Common Loon Habitat” section in Birds of the World, for example, opens with “[Loons] prefer clear lakes….”. The Cornell Laboratory of Ornithology’s page dedicated to the common loon begins with: “The eerie calls of Common Loons echo across clear lakes of the northern wilderness”.

An association between loons and water clarity seems reasonable. After all, loons are visual predators. Why would they spend time in water through which they cannot see?

Yet I learned in Wisconsin in the mid 1990s that loons do not strongly favor clear water. While many of my study lakes, like Alva and Two Sisters, are quite clear and produce chicks regularly, many others, such as Hancock and Oneida, are both turbid and productive. In short, loons in the Upper Midwest thrive and fledge chicks on lakes that vary between 3 and 20 feet of visibility. Indeed a scientific analysis showed that water clarity is not among the factors that dictates use of a lake by loons.

If you think about it, you can understand why a migratory species like the common loon does not overspecialize on water of a certain clarity. As we know from Kevin Kenow’s work, loons fly hundreds of miles across largely unknown terrain and then must land on a waterbody somewhere. If they are in desperate need of a meal at such times — as we might presume — they had better not be too finicky about the menu and the eating conditions. Flexibility must be especially important among juveniles migrating south for the first time, who are crossing terrain that is entirely unfamiliar to them and must find food nevertheless. And, of course, migration begins or ends in the Gulf of Mexico or Atlantic, where both diet and water clarity are entirely different from that during the summer months.

Wait. I posted a blog in the spring detailing the importance of water clarity to loon foraging success and explaining how rainfall was washing material into lakes and reducing clarity to loons’ detriment. Am I now taking that back? No indeed! Water clarity IS important to loon families in July. At that time of year, loon chicks gain mass much faster if the water is clear, and their adult parents maintain body mass better when water is clear. But further analysis has revealed an additional factor that is not so straightforward. I learned just a few weeks ago that loon chicks and their parents actually show lower mass in July in lakes that have high long-term clarity. That’s right; loons have higher masses when short-term water clarity is high but lower masses when they are in normally-clear lakes!

Just to be very plain here, I am saying that short-term water clarity (during the month of capture) increases loon masses because they probably see their food more easily, but some factor related to long-term clarity (how clear the water is on average, over many years) actually makes it harder for loons to put on mass. How do we make sense of this brain-twister?

We can only speculate about the long-term water-clarity-related factor that hinders loons’ foraging. However, there is a prime suspect. Human recreation is strongly correlated with lake water clarity. In other words, people like to spend time boating, fishing, and swimming in clear lakes. During the time when loon parents are trying to stuff their chicks with food, we humans are out there complicating the process by frolicking about in their vicinity. It seems quite plausible that this burst of human activity causes loons to lose precious foraging time and perhaps also access to their favorite foraging spot, if humans are using it. So we can easily see how human activity might cost loons some food and thus reduce mass.

If I am correct that humans impair loon foraging in clear lakes, then we can count breeding on a clear lake as a mixed blessing for loons. Clear water makes food easy to see and catch, but it brings hordes of humans that loons and their young must avoid — which cancels out a good deal of this advantage. Now, if a loon pair were to breed on a lake that had clear water and was inaccessible to humans, they would have it made! Sadly, this seldom happens in our neck of the woods.

In addition to this cool but somewhat distressing news about loon biology, I have distressing and not at all cool news about the Loon Project. We have just lost our primary funding source and are therefore going to be a bit tight for 2023 and perhaps beyond. I am hoping to use a “rainy day fund” to make it through 2023 in Wisconsin. Continuation of the work in Minnesota, which we began only two years ago, is now very much in doubt. If you can consider a donation to help us fight through this lean period — so that we can continue to learn about loon biology in ways that might help preserve the Upper Midwest loon population — we would really appreciate it.

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Photo: The male of the Little Pine-Dream Island breeding pair spent a good deal of time off of the nest in late May of this year, because of black flies. He and his mate fought off the flies, incubated their eggs and fledged two chicks this year. Little Pine Lake, on the Whitefish Chain, is relatively clear, and the male’s purple and white bands are easy to make out.