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A few years ago, a team from Canada learned about the declines in loon populations that have been found by researchers in Ontario and Quebec and by us in Wisconsin and decided that it was time for a documentary. It took the company a few years to make the film available in the U.S., but now it is streaming on Peacock. The title is “Loons: A Cry from the Mist”.

One never knows how these pieces will turn out. The producer tells you that they want to interview you on such and such a date against this background and have you talk about this, that, and the other thing. Of course, you try to steer the interview towards topics that you deem most important. In the end, the producer and editor (I think) stitch together some of your comments and some comments of others to create the best possible story. You can only sigh to learn that your best quips ended up on the cutting room floor.

I cringed at a few aspects of the film. Like many others before them, these filmmakers could not resist the patently false idea that loons are ancient. Mercury, which has been studied for decades yet still has not been shown to have more than weak negative impacts on loons, is portrayed as a likely cause of the decline. The age at which loon chicks reach independence is stated incorrectly. And, of course, I wish I had worn a nicer shirt!

On the other hand, I was proud of how well the 2022 Wisconsin Team handled loon capture. Because of scheduling, filming could only occur on our very first night of capture. Yet Molly, Chris, Sarah, and Claudia shrugged off my nervousness and looked like seasoned professionals. The crew got some dazzling footage from Canada and our Wisconsin Study Area. Their profile of Linda Grenzer and her loon pair, Clune and Honey, is sweet and uplifting. I did not sound like a complete idiot during my bits. Most important, I was able to highlight the high rate of young adult mortality that we are seeing in Wisconsin and the need to understand that recent pattern.*

In short, Yap Films produced colorful, entertaining, and largely accurate loon documentary describing the concerns that conservation scientists have about the species. If you have 50 minutes free, it is worth a look!

*Of course, we now know that the decline results in large part because of poor feeding conditions early in life, which ruin a loon’s chances at a long, fruitful life. Too bad the film was not made a few years later!

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If you have been following my blog, you are aware of a worrisome set of circumstances. Survival of Wisconsin adults is as high now as ever, but breeding success has fallen sharply. And the negative silver spoon effect I detected this fall compounds the reproductive downturn. Underfed chicks are unlikely to survive to adulthood. Those that do survive are unlikely to claim a territory and raise chicks themselves. In other words, Wisconsin breeders produce fewer and poorer quality young than before, which contributes to population decline.

And matters are worse in Minnesota. Our data from northcentral Minnesota show: 1) consistently lower adult survival than in Wisconsin, 2) breeding success on a par with Wisconsin, and 3) a more severe silver spoon effect. That’s right, adult loons in Crow Wing and Cass counties experience lower overwinter survival than their Wisconsin counterparts and have been rearing young of poorer quality in recent years. Here is a figure showing the latter pattern.

As you can see, Wisconsin breeders have actually bounced back to raise healthier young in the past few seasons! This is excellent news, and we hope the pattern persists. But Minnesota breeders have gone the opposite direction. Why is this a concern? As the figure below shows, the probability that a loon reaches adulthood depends upon its mass as a chick.

Thirty two years’ of data in Wisconsin have shown that loon chicks with a mass/age value above 80 have about a 50/50 chance of returning to the study area as adults. Roughly 42% of those with mass/age values of 70 to 80 come back as adults. Chicks in mass/age classes of 60 to 70, 50 to 60, 40 to 50, and below 40 return at rates of 36%, 28%, 18%, and 14%, respectively. Now look at the mass/age data from Minnesota for the past two years:

The future looks bright for the Big Trout-West chick we banded in 2023, the larger Cross-South of Happy Bay chick from 2023, and the Fawn-E chick from this past summer. Things look fairly rosy for both Island-Channel chicks from last year, the Goodrich-SE chick from 2023, the Kimball-West chick from 2023, last year’s Little Star/Star chick, two of three Lower Hay chicks from 2024, the alpha Margaret-North chick from 2024, the chick on North Roosevelt, the Lower Cullen-SW chick from 2024, the larger of two 2024 chicks from Cross-Arrowhead, this year’s Roy-South chick, the alpha chick from Ossie-Island, and the Little Pelican-South chick from 2023. The remaining 51 Minnesota chicks were below average size (56 grams/day). Hence, 75% of 2023 and 2024 chicks from Crow Wing and Cass counties stand very little chance of reaching adulthood. Even if they beat the odds and do so, they are unlikely to produce a single chick.

In light of these patterns, I am getting a sinking feeling about Minnesota loons. Of course, the worrisome data come from only the past two years and one part of the state. Perhaps these years were atypical, and Minnesota loons will bounce back this summer. I hope so!

The featured photo shows the female from Rush Lake-Channel in 2024 as she alertly approaches an intruder. Photo by Isaac Pavalon.

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This seems a dark time for loons in the Upper Midwest.

Wisconsin breeding pairs fledge 26% fewer chicks now than they did 25 years ago. Our more limited data from Minnesota indicate low breeding success there as well. (A long-term study by Minnesota DNR confirms that chick production is decreasing in the state.) The decline in breeding success across the Upper Midwest concerns me. Do enough chicks still reach adulthood so that they can sustain the population of breeders?

But, as I have discussed in previous posts, loss of chicks while under their parents’ care is less of an issue than the escalating die-off of young adult loons after they leave the breeding grounds. Survival in this later stage of the life history is down over 80%. Of 99 chicks that we banded in 1998, 1999, and 2000, we had resighted 38 (38%) as adults by 2004. In contrast, we have reobserved as adults only 9 of 155 chicks (6%) banded between 2018 and 2020.*

Of course, these young adult returnees are troublemakers. They loaf on undefended parts of large lakes or on vacant small lakes. They intrude into breeding territories. Their visits force pair members to confront them physically and steer them clear of chicks. If the pair’s hints are not sufficient to drive the youngsters off, they are attacked. Naturally, the more of these 2- to 6-year-olds there are in the study area, the greater the chance that one of them evicts a member of the pair.

But these young loons are also the future. From their ranks come replacements for breeders that die each year. So young adults — warts and all — are essential to population stability.

The huge drop in the young adult population has turned our annual spring census into a stressful experience. In early May our Wisconsin and Minnesota teams race from territory to territory to see which of our marked breeders have returned and which territories from previous years are still occupied. Each year I fear that breeding lakes will be lost because the dwindling young adult population will be unable to fill breeding vacancies.

In truth, we have lost several of our traditional territories in Wisconsin during the past few years. We did not find breeding pairs on Bridge, East Horsehead, Hildebrand, Miller, Oneida-East, Pickerel-North, Tom Doyle, Swamp, or Muskellunge (Lincoln Co.) in 2024. We seem to have lost one of our breeding pairs on Bertha Lake and another on Butterfield Lake in the Minnesota Study Area as well, although our data do not extend as far back there. Still, there has not been a wholesale loss of territorial pairs in the Upper Midwest, which one might have expected from the high mortality of young adults. So while we have far fewer young nonbreeders milling around, the decline in the territorial loon population is, as yet, small.

Thus, the loon population might be more resilient than we had feared. We have long known that the majority of young loons that return to the breeding grounds never settle on a territory. Perhaps the die-off of young adults merely reduces their number to those few that would normally claim territories anyway. It is a hopeful thought!

Meanwhile, my work continues in both states. I am connecting with water quality specialists in Wisconsin and Minnesota in hopes of learning why we are losing water clarity in July, which harms loon chicks. And I am searching feverishly — both on the breeding grounds and in Florida, where most of our birds winter — for the cause of the high mortality in young adults. These are not quixotic quests. I feel that people who love loons in the Upper Midwest will step up and help them if we can pinpoint the factors that endanger their population.

If you would like to support my efforts to conserve loons in Wisconsin and Minnesota, please consider a donation to our 2025 field effort. We squeeze all we can out of every dollar we receive.

* People sometimes ask me, ”Could these missing loons have simply gone somewhere else? Have they gone to Canada?” It is a reasonable question. Ecologists have marked and tracked movements of thousands of bird species as well as many other vertebrates. With the exception of nomadic species, though, territorial animals like loons stick to a rigid set of guidelines with respect to settlement. If it is still alive, a loon will return to the near vicinity of its natal lake as a young adult to look for a breeding spot. (This is especially true of males.)

The featured photo is by Hayden Walkush of the territorial female on Two Sisters-East. This photo is among the 1906 taken by the team this year as part of our study of whether or not loons can be distinguished using artificial intelligence.

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Almost four years ago, I wrote a blog post about the importance of Florida’s Gulf Coast as a wintering area for loons breeding in the Upper Midwest. I pointed out that 75% of loons breeding in Wisconsin and Minnesota winter along the Gulf Coast of Florida from Pensacola to Fort Myers. And I suggested that conditions in Florida were likely to have substantial impact on the loons we see on our lakes in the north.

My thoughts have returned to Florida of late. Why? Because recent findings suggest that the answer to our greatest riddle might be found there.

Followers of the blog may recall that the single most worrisome pattern related to the Upper Midwest loon decline is the mysterious disappearance of juvenile loons before they reach adulthood. In Wisconsin, the survival rate of juveniles to adulthood plummeted from above 50% to less than 20% between 1993 and 2016, as the graph from our statistical test shows.

The problem has gotten worse since 2016. Only 13 of 209 chicks (6.2%) banded in Wisconsin between 2017 and 2020 have returned as adults. That is a ghastly statistic.

What might be the cause of this massive die-off of young loons? We have good data from the breeding grounds. If juvenile mortality were high during this interval, we would have detected it. Death during migration is another possibility, of course. We do not have good data from that period. But it seems implausible that the varied array of aquatic habitats used by young loons along the migration route have suddenly become a death trap for them.

So it was with increased urgency that I turned my gaze to Florida two weeks ago with our juvenile return data in hand. My hope was to take a second, more thorough look at the likelihood of spotting loons two to four years after we marked them as chicks. I had taken a preliminary glance at this pattern 12 years ago. This time I had: 1) twice as much data, and 2) measurements of physical and biological patterns from ocean water along the Florida Gulf Coast that might help explain the decline. Among physical and biological ocean attributes that I could examine this time were water clarity, temperature, pH, salinity, and concentrations of Chlorophyll A, dissolved oxygen, nitrogen, and phosphorous.

What do the data show? After accounting for observation intensity 2-4 years after banding (which has varied during the study) and location of lake where the chick was banded (because juveniles from central lakes are spotted more often), three variables strongly predict the probability of resighting of a color-marked juvenile loon. In order of decreasing importance, they are:

  • Year — The likelihood of spotting a banded chick as an adult has decreased by an average of 8% from one year’s “crop” to the next. This is the alarming pattern that I seek to understand.
  • Body condition at banding — Chicks that are heavy for their age when banded are much more likely to be resighted as adults.
  • Chlorophyll A level in Tampa Bay in December of the first year — Chicks are much less likely to return if Chlorophyll A levels in Tampa Bay were high in December of their first year (see graph below).

Wait! Does this last finding make sense? First, it is vital to understand that Chlorophyll A is a measure of aquatic phytoplankton — the microscopic algae that can make water appear green to us. A very high concentration of Chlorophyll A can indicate an “algal bloom”, which reduces water clarity and can lead to loss of oxygen and release of toxins. Second, it is important to understand that the negative impact of Chlorophyll A on loons occurs only in December of a loon’s first winter. Return rate of juveniles is not associated with Chlorophyll A levels the month before (November) nor the month after (January). Third, we must be familiar the the migration schedule of juveniles. Juveniles reared in Wisconsin and Minnesota typically reach their Florida winter quarters in late November. Stitching all of this together, the negative impact of Chlorophyll A in December on return rate to Wisconsin suggests that many young loons perish in their very first month on the wintering grounds in Florida if algal levels are high at that time. We would expect these neophytes to be at risk during this period, because they must suddenly find new aquatic prey in wholly unfamiliar habitat. High algal levels add another layer of difficulty to foraging, likely reducing the abundance of prey as well as a loon’s ability to find them.

Of course, this is a hugely important finding. This is the first evidence — to my knowledge — where an occurrence in winter affects a demographic pattern detected on the breeding ground. The effect, moreover, is strong. And the pattern is evident despite the fact that Chlorophyll A data represent only one small part of the winter range (Tampa) that is as far as 350 miles from where some Wisconsin loons spend the winter. We can reasonably surmise that the pattern would be far stronger if we had complete data from all along Florida’s Gulf Coast and could match locations of wintering loons up with Chlorophyll A data from their exact location.

Unfortunately, this striking finding cannot explain the steep decline in juvenile survival rate over the past quarter century. Why not? First, Chlorophyll A levels have remained roughly stable in Florida — maybe even falling slightly — across the two decades or so when juvenile survival has been getting steadily worse. Second, the statistical decline in annual return rate among young adults remains strong even after we have accounted for the effect of Chlorophyll A.

In short, many of our first-year loons do appear to die in Florida, shortly after arriving there. But we are still utterly in the dark with regard to the continuing yearly decline in young adult survival. Young adult loons are future breeders — essential to the stability of the Upper Midwest loon population. It is urgent to learn what is killing them. I will keep looking.

The featured map is from Google Earth. It shows lines drawn between where a loon was banded in summer and where it was recovered or spotted during winter months. Green end points indicate Wisconsin breeders and red indicate Minnesota birds.

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If aliens landed on Earth’s surface to investigate its life forms, they would be puzzled by the coexistence of common loons and humans. True, loons spend almost their entire lives on the water, where they are relatively free of dangers from humans and other terrestrial vertebrates. But loons require solid ground for nesting, safe “nurseries” for rearing their chicks, and abundant food to keep themselves and their chicks alive. How, then, can loon populations persist along the southern periphery of the species range, where humans and human recreation threaten all three basic requirements?

The ability of loons to thrive in regions of intense human building and recreation vexed me for several years in the 1990s, when I first began my long-term loon research. I could see that most people venerated loons and took pains to protect them. But the sheer abundance of humans surrounding, approaching, and fishing near adults and chicks during the spring and summer made the tasks of hatching young and rearing them to adulthood seem daunting. How did loons manage to raise any young in the northern U.S. and southern Canada?

I cannot answer this question completely. I am still amazed at the abilities of adults and chicks on busy lakes to dodge motorboats and jetskis as well as they do. And it continues to surprise me when adults fledge chicks from small lakes where food seems limited. However, detailed study of loons’ nesting patterns allowed me to solve one riddle: how loons enjoy high nesting success despite intensive shoreline development.

One would think that shorelines are essential to nesting loons. Loons have to nest along shorelines, right? And humans build summer homes along shorelines too. So loons and humans would seem to be direct competitors for shoreline habitat. But it is not so. Why not?

The answer is deceptively simple. Well-drained “upland” shorelines provide the best sites for building lakeside homes. Upland sites are free of boggy or marshy vegetation. At the same time, upland shorelines provide poor nesting habitat for loons. Most loon eggs placed on upland shorelines end up in bellies of raccoons that take advantage of the comfortable footing they provide to look for easy meals. Experienced male loons learn to avoid placing nests on dry, upland shorelines.* Instead, they usually locate nests on islands, marshes**, or bogs hard for terrestrial predators to reach.*** So one key to loons’ ability to coexist with humans is merely loons’ preference to nest where humans cannot build.

Hodstradt Lake in the Wisconsin Study Area illustrates the complementary use of shorelines by loons and humans. Hodstradt is a 119-acre lake that has beautiful clear water with a slightly greenish hue. The lake is full of fish but completely encircled by lake homes. There is no island, marsh or bog in Hodstradt — only a peninsula in the southeastern corner (see screen grab below from Google Earth). Almost all nesting attempts by loons on Hodstradt have been on the end of that peninsula. High water caused by heavy rainfall in the past decade submerged the narrow spit connecting the end of the peninsula to the mainland, making it a small island. Whether an island or a peninsula, though, the land is low lying and impossible to build on. Hence it provides permanent nesting habitat for loons that is off limits to humans.

A similar situation exists for many loon pairs in the Minnesota Study Area. The seven pairs that nested this year on massive Cross Lake provide a good example. Three of these pairs nested on small uninhabitable islands; three nested among dense cattail patches in marshy coves; and one used an artificial nesting platform. (Five of these pairs hatched chicks.) Thus, the “Jack Sprat” nature of loon and human shoreline use can be seen in both Wisconsin and Minnesota. With rare exceptions, sites safe for loon nests are sites where humans cannot or will not build.

So adult loons are able to put chicks in the water despite extensive shoreline development. This would seem to be cause for celebration. In a cruel twist, though, shorelines altered to support suburban-style homes, lawns, and driveways have increased runoff. Although we are still working out the details, it appears that higher runoff has, in turn, produced a decline in water clarity and decreased chick mass, probably because adults cannot see fish well enough to provision their chicks adequately. In short, shoreline development negatively impacts loons during the second critical breeding phase: chick-rearing. Indeed, the sharp increase in mortality of chicks and young adults in the past two decades has become our number one concern with respect to the Upper Midwest loon population.

If there is a silver lining, it is this. Loons are resilient. They have been able to find nesting sites and sustain a high hatching rate despite everything humans have thrown at them. Perhaps we can help loons reverse the decline in chick survival, if we can learn precisely what is driving the drop in water clarity. This will be a massive challenge. But I have to believe that loons can come back from this setback. It keeps me going.

* We learned 16 years ago through marking of loons and systematic tracking of nest placement that male loons choose the nest site. For those not interested in looking at the science, we know this from two facts. First, loon pairs learn where to nest by trial and error. That is, they tend to reuse a site where they hatched chicks the previous year but move to a new nest location after egg predation. This logical nesting strategy is called the “win-stay, lose-switch” rule. Second, loon pairs in which the female pair member returns from the previous year but the male pair member does not usually do not reuse a successful site from the past year. In contrast, pairs consisting of the male from the previous year and a new female tend to reuse successful sites. In short, pairs with new male members do not use the win-stay, lose switch rule. They act as if they have forgotten where the best nesting site is.

** The featured photo is of Clune, Linda Grenzer’s favorite male loon, who bred for many years in her lake in Wisconsin. He is incubating eggs in a marshy corner of the lake that, predictably, is devoid of homes.

*** Of course, humans often accomodate loons’ nesting preferences by placing artificial nesting platforms along lake shores. Platforms provide very attractive nest sites for loons.

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Loon pairs experience many setbacks during the course of a breeding season. Black flies drive them off of nests in May. Eagles take chicks. Intruders force them to expend energy in territory defense or even evict them. Rainfall clouds the water, making it difficult to find food for chicks. It is largely a pair’s ability to bounce back from such adversity that determines how successful they are at fledging young.

The loons at Big Trout-Far West, part of the Whitefish Chain, faced more than their share of challenges this summer. All seemed good in May, as the pair shared incubation duties on their two eggs (see photos above by Karl Olufs*). When they hatched two healthy chicks on June 9th, the veteran male and female breeders seemed poised for a fruitful year. But their luck turned. On June 12 a freak storm dropped golf-ball-sized hail to across much of the Minnesota Study Area. One three-day-old chick took refuge under a camp’s pier, while the second remained out in the chop. Following the storm, the exposed chick was found dead on shore, and only its sibling remained. In a poignant moment, one of the parents left the water and sat on shore beside the deceased chick, before returning to tend its surviving sibling.

Three-and-a-half uneventful weeks passed, and the surviving chick grew. On July 6th, though, the male, who had been healthy the day before, died suddenly and violently, a likely victim of a boat or jetski collision. For a few days, the female cared for the chick alone. But a new unmarked male soon noticed the lack of a male defending the territory and joined the female. Unwilling to rear a chick not his own, the new male grabbed the chick, shook it violently — as a horrified lake resident looked on — and killed it. In a month’s time, the original family of four had been reduced to one.

When Richard Rammer and I visited the Far West pair on July 26th, they were resting quietly in their marshy cove, as if in recovery. The female cooed repeatedly to her new mate, trying to coax him to search for a nest site. He sat quietly a few meters away, unmoved. There was something touching in the female’s stubborn unwillingness to accept defeat. Battered as she was by misfortune, she was looking forward — seemingly determined to lay the groundwork for a successful 2025 breeding season.

As horrid a year as the Far West pair had, they are only one pair. Elsewhere on the Whitefish Chain, the news was better. The pair at Island-Channel, which adopted a doomed chick in June, still had both their biological chick and the fostered one. Despite the apparent vigor of both chicks, I had nagging concerns. Was the biological chick getting more food? Were the chicks still bickering? The scale told the story: both chicks weighed in at a strapping 2.42 kilograms on the night of July 20th, when we caught the entire family.** Their future looks bright. Good news emerged too from a second pair on Island Lake, which abuts the Island-Channel territory. There an unmarked pair have raised a chick to five weeks of age and are likely to fledge it.

Even on Big Trout, where boat traffic is constant and rapid, a glimmer of hope emerged. Big Trout-Central, a few miles east of the ill-fated Far West pair, has raised a chick that recently turned five weeks of age. If it can dodge boats, jetskiers, and eagles for the rest of the summer, it will be the first fledgling from that territory since 2020.

Cross and Rush Lakes each contain three breeding pairs with chicks. The total of eight chicks between the two lakes is mediocre, considering the dozen territories they support. Still, among the chicks is a singleton produced by an all-new Rush-Boyd pair that bounced back from a chickless year in 2023.

Daggett Lake had an off year. Neither the Northeast nor Southwest pair hatched eggs, while the Channel pair hatched two healthy young from an island but lost them in the first two weeks. On the other hand, the Little Pine-Dream Island pair is enjoying their fourth consecutive productive season, raising two enormous independent chicks just north of the channel from Daggett. The news is also good from Pig Lake, where a new pair is raising two huge chicks after an off-year in 2023. The pair on Bertha, chickless for the past three years or more, also has two gigantic eight-week-old chicks. Sadly, the Upper Whitefish-Steamboat pair lost two small chicks in the same freak storm that cost one of the Far West chicks its life. But two of four pairs on Lower Hay (Northeast and Southeast) have chicks that are fit and strong. By raising a chick this year, the Northeast pair broke a slump of at least three years without young.

Loons in the Outing/Fifty Lakes section of the Minnesota Study Area, like those on Cross and Rush lakes, were only moderately productive. Roosevelt and North Roosevelt, between them, yielded only two fledged chicks this year. West Fox and East Fox pairs looked good early in the year. But the disappearance of the East Fox-South male resulted in loss of two chicks, in spite of the heroic efforts of the female to rear them alone. Furthermore, late loss of a large chick on West Fox-Stone Man whittled down the productivity to three chicks between the two lakes. Eagle Lake, similarly, yielded only one fledged chick. A mere two chicks emerged from Eagle, Kego, Butterfield, and Mitchell lakes combined this year, in contrast to the six produced in 2023.

There was a pleasant smattering of chicks on small lakes in the Crosslake region. Goodrich-West and -Southeast pairs both raised chicks successfully, and two new breeders on O’Brien beat all odds by hatching a late chick there. Kimble-East was a washout, but Kimble-West, Clear-North and -South, Star, Big Pine, and Grass lakes together raised eight chicks.

Lakes in the southwestern portion of the study area had an especially impressive breeding year. Ossie pairs raised five chicks in all. Pairs on Upper Hay, Nelson, Sibley-North and -South, Fawn, West Twin and the Cullens produced chicks at above-average rates, as did those on Roy-North and Roy-South and Nisswa. Pairs in the Upper Gull area did particularly well, including Mayo Creek, Boathouse, Bass Lake and Margaret-North pairs.

In short, the cruel summer at Big Trout-Far West did not typify the breeding season overall for the Whitefish Chain or the Minnesota Study Area as a whole. Stepping back to view the season from space, it was a decent breeding year. Low and short-lived populations of black flies early in the year helped get the season off to a solid start. Alas, the abundant rainfall we have had this spring and summer means that we cannot count on the continued paucity of these pests in 2025. For the moment, though, let’s shrug off the disappointment at Big Trout-Far West and enjoy the rather productive breeding year for loons in central Minnesota!

* Thanks to Karl Olufs and his sister, Janet, who paddled her kayak out to meet us on July 26th to relate the saga of the Big Trout-Far West pair.

** The male of the Island-Channel pair is an interesting loon in his own right. Hatched in 2016, he is among the handful of loon chicks marked with silver numbered bands by Kevin Kenow of USGS. Upon his capture, we read the number etched into his band and discovered that he was raised on the Big Island territory on Upper Whitefish in 2016. Thus, he is a whippersnapper at 8 years of age. He is the first known-age loon to settle in the Minnesota Study Area.

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Loon’s inhabit an unpredictable natural world. Black flies swarm them early in the year, often making incubation impossible. Coyotes, fishers, eagles, and raccoons ambush them on nests and take eggs — and sometimes loons themselves. Eagles swoop by unexpectedly to grab a chick that strays.

It seems unfair to add humans to the mix. Yet humans pose by far the greatest danger to loon survival and reproductive success. High summer brings a surge of anthropogenic challenges: some mild, some severe. Boaters unwittingly push loon families out of their favored foraging locations. Jetskis elicit yodels and tremolos from loon parents fearful for their chicks. Inattentive — and occasionally malicious — boaters deal a deadly wing or neck blow to an adult loon or chick. Anglers hook loons and cut fishing lines. Of course, we now understand that indirect impacts on northern lakes — especially loss of water clarity — pose the greatest threat of all to loons.

Some human impacts on loons are difficult to fathom. The July 4th holiday celebrations — always feared by loon enthusiasts and researchers — affected loon families on Roy Lake, Minnesota, in a manner that we had not seen before. We knew that surges in boating, fishing, and general hijinks would force loons to spend much of the holiday ducking, dodging, and diving. But we did not anticipate that fireworks and boats might scramble up loon families.

The precise events are difficult to discern. Here — according to Sheila Johnston and folks on Roy who watch the two breeding pairs closely — is what we know. On July 2nd, the Roy-South loon pair had two huge chicks. That night, many boats criss-crossed the waters of Roy-South to watch the Grandview Lodge — a large resort on Roy — shoot off a massive fireworks display. The following day one of the two chicks from Roy-South was missing. On the same day, the Roy-North breeding pair, which had two medium-sized chicks on July 2nd, suddenly had three: their own two and a much larger one. The only plausible explanation for these events is that one of the two Roy-South chicks became disoriented by the boisterous flotilla during the previous night, blundered into the North pair, and unwittingly abandoned its own family to join a new one. (Sheila Johnston took a photo that shows the “monster chick” from the south end next to one of the smaller chicks from Roy-North.)

There is good news. The adoptee has been fully accepted by the Roy-North pair and its two smaller step-siblings. All three young are being fed by the parents. So what could have been a human-induced disaster became a sweet story of a loon family willing to accept an unrelated chick that had lost its way. Loon lovers can, in this case, breathe a sigh of relief.

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Sibling rivalry is a fascinating but intellectually thorny behavior pattern. Why would a young animal hurt its own flesh and blood? To put it scientifically, why would an animal harm its full sibling when that sibling shares half of its genes and when the ultimate goal of animal behavior is to increase the abundance of one’s genes in the next generation?

But normal rules do not apply when food is limited early in life. If the food supply is inadequate to keep all members of a sibling group alive, then the only sound evolutionary strategy for each sibling is to battle mercilessly and become a survivor.

Such is often the case in loon families, especially those living on small lakes. Even with only two chicks to care for, loon parents are all out to keep them alive. This scenario creates the haves — chicks that hatch two days before their siblings and use their size advantage to pummel them and gain a greater share of the limited food that parents can find — and have-nots.

What of the have-nots? To avoid beatings from an aggressive older sib, a typical younger sib lags behind its family and, as a result, receives fewer feedings. It becomes weaker over time, is less able to defend itself, suffers more beatings, and begins to avoid its family altogether. Unable to escape this downward spiral, most beta chicks perish from starvation. Some undoubtedly fall prey to eagles.

But not all starving beta chicks die quietly on their home lakes. Sometimes a chick in such dire straits abandons its home and kin and strikes out over land in hopes of finding a new family of loons that will feed and protect it. If it sounds preposterous that a weakened, helpless loon chick would trek through the woods in hopes of being welcomed by a foreign loon family, it is. Only the prospect of certain death at home could induce a chick to make such a reckless, fanciful journey. And yet such “chick odysseys” happen commonly at this time every year.*

We are four weeks into the chick-rearing period in both Minnesota and Wisconsin study areas. So this is the time when a small cohort of starving second-hatched chicks from small lakes across the Upper Midwest are abandoning their abusive older siblings to seek a better life elsewhere.

A two-week-old chick in north-central Minnesota took this desperate approach. A good samaritan stumbled upon the brown puffball on a roadside and carried it a rehabber. But the rehabber had no future to offer the chick. Only loons can raise loons. In fact, only adult loons who currently have chicks of their own are (sometimes) willing to accept these waifs.

It is a chancy business to match a parentless chick with a foster family already rearing a chick. The chief danger is lack of acceptance by the biological chick. If the natural chick attacks the chick you are trying to add to the family, you are back to square one. Folks who attempt fostering of this kind report a success rate of about 35%.

The loon pair of Island Lake on the Whitefish Chain had a single two-week-old chick — very close to the size of the chick found on the roadside. As shown in the video below, the homeless chick quickly joined and bonded with the Island family. After an initial tussle with its new sibling ended in a draw, the biological chick seemed to resign itself to the new addition. Both chicks remained peacefully together this afternoon, three days after the introduction.**

Introduction of rehabbed chick at Island Lake, Whitefish Chain, Minnesota.

We have no idea what the future holds for the adopted chick. Starvation, predation, a boat strike, or fishing entanglement might end its life before it reaches fledging age. Yet a chick that was a longshot to survive two days ago is suddenly ensconced with a protective new family. And this former have-not now stands a decent chance of reaching adulthood. It is hard not to feel good about that.

* Though these journeys are the most desperate of long-shots, they do not always fail. In fact, we had one case where a chick that fled across land reached a new lake, gained two new siblings, and lived happily ever after.

** The top photo shows the Island Lake pair and their two chicks as of June 28th at 1pm. Evrett Fiddian-Green, who took this photo, reports that both chicks are being fed by the parents. Most important, the chicks are not fighting.

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I was skeptical when I first got the news from Melonie and Gin on East Fox Lake in Minnesota. “Larry”, they said, “has been missing for weeks.” Melonie and Gin have a bird’s eye view of the bay where the East Fox-South pair nests.* They know the bands of both adults, whom they call Larry and Lola. Very little that occurs on the territory escapes their notice. “We watch our pair like others watch TV”, Gin told me recently.

I should not have doubted them. And yet I am a scientist and have studied loons for 32 years. I am used to hearing reports of loon behavior that range from strictly factual and incisive……to 50% truth and 50% dramatization to….well, pure fantasy. So I followed up. “Missing?” I said dubiously. “He has not been positively identified since June 5th,” Melonie replied, “and we have seen only Lola incubating the eggs since at least a week before that.” She added that stretches of many hours had passed in early June during which Lola was off the eggs. Larry, who should have been incubating at such times, was not present. My team’s visits too confirmed Larry’s sudden absence.

I was convinced. Larry had vanished sometime in late May or early June.

Members of breeding pairs occasionally disappear. That alone is not news. Lead poisoning from fishing tackle, boat strikes, disease, and territorial battles sometimes claim one pair member in the middle of a breeding attempt. Faced with the loss of a mate, most adult loons — male or female — make a gut-wrenching but rational decision. They suspend the breeding effort, wait to find a new mate, and attempt to breed again later in the season, if time permits.

But Lola did not give up. In fact, hers is the first case we have documented of a loon of either sex losing its mate during incubation and incubating the eggs alone.** When both eggs hatched successfully on June 7th, Lola became a single mom.

Parenthood is a stressful business among loons. Lola had already challenged herself by choosing to warm the eggs on her own. Her obligation to protect and feed the two helpless hatchlings that emerged from those eggs raised the bar considerably.

I am not knocking Lola herself or females generally by describing the pickle she is in. Lola is a seasoned breeder who has proved she knows how to raise young. But female loons are 20% smaller than males. Indeed, at 3580 grams, Lola is slightly smaller than the average female. The real handicap that single loon moms face is the lack of a crucial vocal tool. You see, male parents save their families considerable time and energy by yodelling to discourage intruders from landing near the chicks. Lacking this vocalization, Lola must respond to territorial intruders either by hunkering down and hoping to remain unseen or confronting the intruders while stashing the chicks near shore.

The two chicks at East Fox-South are now two weeks old. As Melonie’s photo shows, they look good and are being fed steadily by their devoted mom. They are also of similar size, which suggests that Lola has been able to satisfy the needs of both chicks and prevent the corrosive sibling rivalry that often occurs in two-chick broods. But the family still must survive countless territorial intrusions and eagle flyovers before the chicks reach independence. Keep a good thought for them!

* Thanks to Melonie Elvebak for this nice photo of Lola alertly watching out for her brood.

** Back in 2005, a male on Alva Lake in Wisconsin faced a similar choice to Lola’s. An eagle killed his mate on the nest. Like Lola, he incubated the eggs alone for several days. But ultimately he could not balance his breeding attempt with his need to keep himself alive and healthy. So he gave up.