Science, of course, is cumulative. Solving scientific riddles generally requires multiple studies by diverse authors using a broad range of scientific techniques. In fact, scientific conclusions are more compelling when they rest upon findings from many scientists using different techniques and with different backgrounds.

So I was quite anxious to learn what Kevin Kenow had found. Kevin, a scientist with the U.S. Geological Survey and also a member of the Scientific Loon Council at the National Loon Center, has studied common loons for about as long as I have. But while I have focused on the behavioral ecology of loons exclusively and established two fixed study populations for this purpose, Kevin has collected data on many species of migratory water birds, tackled questions related to human impacts and conservation, and worked across a variety of states and waterbodies in the Upper Midwest and beyond.

Kevin’s just-published article pulled together data from loons in Michigan, Wisconsin, and Minnesota. In contrast to my low-tech methods, Kevin’s team used satellite transmitters and geolocator tags to either: 1) track loons’ migratory movements in real time or 2) reconstruct their movements, following recovery of the geotags.

Kevin’s team confirmed several migratory pathways that we had known about or suspected through recoveries of dead birds. First, adult loons from the three Upper Midwest states typically “stage” on Lake Michigan in the late summer and early fall, before departing southwards to the Florida Gulf Coast. Second, juvenile loons (those only a few months of age) do not visit the Great Lakes prior to migrating south. Third, first- and second-year loons that are too young to return to the breeding grounds instead migrate northwards in the Atlantic, summering off of the Canadian Maritime provinces. The quirky patterns in loon migration and wintering behavior are important. They make it clear that a loon’s survival to the breeding stage requires that it survive and remain healthy across a period of many months, a variety of water bodies, and a number of geographic areas.

But one of the patterns that Kevin’s team identified loomed above the rest. They found a high rate of mortality among first- and second-year loons, especially in the spring. If you are following this blog and have an excellent memory, you recall that this finding appears to dove-tail with a recent one of ours. We found that “floaters” — the segment of adult loons that are two to five years old and are looking for breeding territories — have been disappearing at a high rate. Floaters alone, you might recall, account for most of the decline we have detected in the Wisconsin breeding population.

Do Kevin’s findings of high first- and second-year loon mortality solve the riddle of what is ailing the loon floater population in Wisconsin? Unfortunately not. In fact, we had long suspected that young adults would die at a higher rate than older adults, because they are less experienced. High mortality among young adults is a common feature of avian populations everywhere. But these new findings might help narrow down the “period of vulnerability” in the life history of loons. And our findings of high young adult mortality in the last decade combined with those of Kevin’s team might tell us where to look. Perhaps conditions along the Florida Gulf Coast and/or the Atlantic have deteriorated recently, causing higher than normal mortality during this trying time of life for young loons. This is only one hypothesis, and it will require rigorous testing. Thanks to Kevin’s team’s cool recent findings, though, the wheels of science are turning.

By the way, follow us on Instagram, if you like, at @loonproject. The whole LP team works together to post cool, informative “loonstagrams”!

It is one thing to lose your own young very early and then — at a weak moment — adopt young of another species that resemble your lost young. Adoption after hatching is an inherently risky move, and one likely to saddle you with the responsibility of rearing young very unlike yourself.

But how can things go sideways when you spend four long weeks on a nest and observe carefully as young emerge from the eggs you warmed with your own body? Surely any creature that fights its way out of an egg that you have incubated lovingly beneath you for so long must be worthy of your protection.

So it must have seemed to a breeding loon pair in northwestern Montana two days ago when three fluffy youngsters hatched and dutifully followed their parents onto the water. Yet the fluffy youngsters that popped out of the eggs the loon parents had spent countless hours incubating were not loon chicks, but Canada Goose goslings. So those cold nights, scorching afternoons, and relentless flying pests that the parents endured for four long weeks have produced a surprising outcome.

The loon parents do not seem disappointed. They have spent the past two days attending untiringly to their adorable, if unexpected, brood. And the goslings themselves betray no hint of alarm or discomfort — even when their parents vanish suddenly beneath the lake’s surface.

But Bob LeBlanc, the photographer who discovered this mismatched family, was left scratching his head. After hearing him recount the story of how a loon pair ended up with three goslings, I could shed no new light on the situation.

Certain facts seem clear. First, a goose pair nested on one of Bob’s three carefully constructed (for loons) nesting platforms but then inexplicably abandoned a clutch of eggs soon after incubation began. Finding an attractive nesting location, a later-arriving pair of loons apparently skipped the step where they deposit their own eggs there and instead simply decided to warm the eggs already on the platform.

I’ll be honest. As someone who has devoted his last three decades to learning about common loons and promoting their conservation, I have decidedly mixed feelings about loons raising goslings. The Canada Goose population in the Upper Midwest does not need loons to raise more of them. In fact, according to a recent study, there are about five times as many geese in North America now than in 1970. Goose numbers continue to rise in the Upper Midwest, where I do my research, leading me to worry that they are seizing good nest spots and keeping loons from using them. But for the moment, and in this one loon family, I have to admit that the fuzzy misfits are awfully cute.

Since we band hundreds of loon pairs, we get used to losing pair members here and there. The female on Sunday Lake, newly-banded in 2020, did not return in 2021. Likewise there is a new male on Clear2-Seven Islands, a new female on Towanda, a new male on Harrison Flowage. Some losses of old pair members are gut-shots. The absence of both pair members at Arrowhead reminds us of the tragic close to that lake’s 2020 breeding season. The Baker male’s disappearance is bittersweet; it brings back the recollection of his having reared a mallard duckling in 2019 with his mate. But after many years of watching breeders vanish, I now greet most such losses with only a sigh.

A bit more unsettling than mere disappearances of single birds — and far more interesting to a behavioral ecologist — are cases where breeder loss on one lake has ripple effects on lakes nearby. Since such domino effects seem to occur shortly after ice-out, when our lake coverage is spotty, we must usually guess at what transpired. In 1998 for example, the McGrath and North Two males, which defended adjacent lakes, seemed to switch places for no obvious reason. We inferred at the time that the huge North Two male flew over and evicted the smaller McGrath male, while the McGrath male assuaged his loss by settling on North Two, which his conqueror had just vacated. But we will never know for certain. A similar mystery occurred last year on Upper and Lower Kaubashine, whose males swapped lakes early in the year, before we were there to see how it happened. Again, we surmise that one male evicted the other, and the loser merely filled the victor’s breeding slot.

This year, we had enough observers present at critical moments to read the ripples more precisely. Following the eviction of his mate on May 3rd (Linda’s photo shows that evicted female), the Upper Kaubashine male — yes, the same male that had swapped territories in 2020 — must have decided that his breeding prospects were dim on Upper Kaubashine. So he looked nearby for an alternative. He found it on Silver, a small lake with an artificial nesting platform and a resident, Pat, who misses nothing. On May 9th, the Upper Kaubashine male intruded onto Silver, where the pair was incubating eggs, beat the resident male severely, and forced him to take refuge in a swampy area. The defeated male has not been seen since.

There is a ray of sunshine to share. The Upper Kaubashine male had no interest in sitting on the eggs of his predecessor at Silver, so the lake’s first nest was abandoned. But the usurper wasted little time renesting with the old female at the opposite end of the lake. Boosted in part by the earliness of ice-out this year, the Upper Kaubashine male might actually survive the loss of his mate and a vicious territorial battle of his own and still hatch chicks in June!

The events of the past few weeks on Upper Kaubashine and Silver reveal that chaos on one lake can spill over to others nearby. So if loons are capable of hope, they should hope for peace and tranquility for their neighbors as well as themselves.

As promised, we have begun to cover not only our original Wisconsin study area — in Oneida, Lincoln, and Vilas counties — but also territorial loon pairs in and around the Whitefish Chain, near Crosslake, Minnesota. This has not diminished our research in Wisconsin at all; we have exactly the same number of interns and field effort as in recent years. But we have increased the size of our field team and added Minnesota to the mix.

I have spent the past three days in the new Minnesota study area with three team members. Two of these folks — Katy and Jordana — will remain in Minnesota for the rest of the summer. They will scout out territories that we will begin to cover and also locate pairs with chicks, which we can capture and mark with leg bands. Following an intense banding campaign in July and August, we hope to have 40 or so territorial pairs in Minnesota marked and ready for study by late summer 2021 and perhaps 60-70 pairs by August 2022. We have learned quickly that Minnesota loons are even more tame and easy to observe than Wisconsin loons on average. So things look very promising for our research in the new study area.

After an early ice-out and a less severe black fly emergence than usual, both Wisconsin and Minnesota are seeing their first chicks. The featured photo for this post, taken by new team member, Kimi, shows some new arrivals and their tame parents from the Whitefish Chain. Many more pairs in northern portions of both states are within a week of hatching, like the incubating female below from Upper Whitefish, which was well hidden in

vegetation. So we are seeing the beginning of a wave of earlier-than-normal hatches in both Wisconsin and Minnesota. Breeding productivity looks to be far better this year than in either 2019 or 2020. In light of my concerns about the Wisconsin population, I am relieved to see reproductive numbers bounce back up this year. Let’s hope that this apparent breeding recovery continues.

By the way, we are now on Instagram! If you wish to see loon photos and video from Minnesota and Wisconsin in this much splashier format, follow us at @loonproject.

Few territories in the Wisconsin Study Area rival Flannery Lake in the futility of its breeding efforts. Despite at least one breeding attempt annually, Flannery has hatched only nine chicks since 1996. If that does not sound too bad, then consider that only two of those nine chicks reached ten weeks of age — the age at which young juveniles can be considered to have fledged. Moreover, one of those two fledglings was severely emaciated as a consequence of its father’s death, the father’s replacement by a new male, and the stepfather’s cruel treatment of it. We are quite doubtful that this unfortunate juvenile made it off the lake and migrated.

We cannot blame Flannery’s poor breeding record on the ineptitude of a few breeding adults. Over the quarter century of fruitless breeding attempts, four different males and four different females have ruled the lake, incubated eggs, and witnessed the loss of the nest or young. Each adult, in turn, has — it would seem — fallen victim to the lake’s curse. The breeding drought of the lake appears even more peculiar when one considers that Flannery was the most consistent and productive lake in the study area from 1991 to 1995. It is as if someone threw a switch in winter 1995, and the lake’s fortunes turned.

A cruel irony of Flannery’s reproductive struggles is that it possesses two clear hallmarks of a successful loon territory. The lake is both large enough — at 141 acres, counting its attached sister lake — and rich enough in nesting habitat — multiple islands — that we might have expected better. Indeed, every regular lake in the study area has outproduced Flannery in chicks, including dozens far smaller and with less suitable nesting areas. How has Flannery been able to do so little with so much?

Does Flannery merely typify the pattern of reproductive decline that I have mentioned so many times in recent blogs? That is, is Flannery simply a victim of the reproductive downturn that has hit all lakes in the area? No, the downturn of Flannery occurred much earlier and is far steeper than the downward slide of other study lakes. Flannery is truly unique.

I cannot solve the puzzle of Flannery’s demise as a chick-producer. I have consulted lake residents to learn why so many nests placed in safe locations have been inexplicably lost, so many healthy chicks have vanished without explanation. Some residents, like me, are getting a bit paranoid about the pattern. One said, years ago, that they thought “teens” might be to blame for disturbing nests and perhaps even taking eggs. But that possibility does not pass muster; surely teens that started hounding the loons or grabbing eggs in 1996 would have grown up and ceased this behavior by now.

Despite my unpleasant experience in tracking Flannery’s breeding history, I hold out hope for them each year. This year, I always think…..THIS year will be the one when they turn it around. In 2021 and from now on, perhaps, Flannery will come to resemble Muskellunge, a lake of similar size to Flannery and less breeding habitat — and one that has produced ten times as many chicks. Owing in part to the diligent egg-turning of the male and female there (see Linda’s photo), Muskellunge should hatch their eggs (again!) within a few days. Maybe Flannery will become the Muskellunge of the 2020s. Quite frankly, I do not see why not.

Many species of animals have evolved behavioral rules or mechanisms that help them avoid pairing, mating, and producing offspring with close kin. Plants face this danger too, and the majority of plant species have evolved their own ways of not fertilizing themselves (“selfing”) or doing so only as a last resort. The reason to avoid such inbreeding is a simple one; mating with one’s self or a close relative increases the likelihood that two unfavorable alleles (“versions” of a gene like the “A”, “B” and “O” types in the human blood system) can come together in an offspring and produce an unfavorable outcome.

I thought I understood the mechanism for inbreeding avoidance in common loons. Twenty-nine years of research supported a simple conclusion. Loons avoid mating with close kin, it seemed, because males never settle to breed on their natal lakes. Thus, they avoid the obvious danger of forming a mated pair with their mothers.

Let me back up. Male loons, like males of most birds, do not move very far from their natal lakes to breed. Indeed, males often claim breeding territories on lakes adjacent to where they were hatched and reared. Females show much longer distance natal dispersal, typically breeding a half-county or so away from where they were raised. So the main inbreeding threat that loons face is the possibility that young males will return and pair with their mothers. Father-daughter pairs are not an issue.

In fact, males do occasionally pair with their mothers. On four occasions we have recorded young males to return to the breeding grounds and settle on lakes next door to their natal lake, only to meet and pair with their mom there. How? Females are sometimes evicted from their territories. When this happens, they commonly re-settle near the territory they lost. This places females in the path of any son from four or years before that also happens to also settle there.

The fact that males and their mothers only interbreed in instances when female eviction coincides with settlement of a son appeared significant to me. I reasoned that, since young adult sons were unlikely to happen to choose the same lake where their mother had taken refuge following eviction, loons were using a pretty reliable rule to avoid mother-son pairings. The rule seemed to be that males never chose to settle on their natal lake, thus avoiding the great risk that they would pair with their mother on the lake where she reared him.

Many of you are thinking: “Wait, why would close kin ever form mated pairs? Don’t loons recognize close kin?”. We do not know the answer to this question definitively, but the fact that there are any mother-son pairs at all suggests loons do not know their relatives. If either moms recognized sons or vice-versa, then that recognition would cause them to avoid incestuous pairings.

Let’s turn our attention to Arrowhead Lake in 2021. The tragic fracture of the breeding male’s humerus in 2020 created an opening for a new male on Arrowhead. But the non-return of the female in 2021 meant that both male and female breeding slots were open. The female that took over ownership was a 16-year old from Vilas County. This event was unsurprising. But the new male — at least as of five days ago — was the first-ever male to settle on his natal territory. What is remarkable about the settlement of this four-year-old is that it coincided precisely with his mother’s disappearance from the lake.

As a scientist, I habitually view coincidences not as such but as meaningful statistical patterns that can teach us about the world. So I have an inkling that the first-ever settlement of a male on his natal lake is the beginning of a revealing pattern. Perhaps loons really do recognize close kin in some instances. Perhaps this male, only four years removed from the egg, remembered his mother, recognized that the new female on his natal lake was not her, and seized a rare opportunity to settle at home while dodging inbreeding.

The problem with my hypothesis is that it will take a long time to test. I suppose that we can satisfy ecologists’ desire for statistical significance if we detect three more settlements of young males on natal lakes just after their mother’s disappearance. At a rate of one such event each 29 years, it will take 87 more years to reach statistical significance.

So…..we have some time. That being the case, take a moment to study the photo I took today on Long Lake, which shows two eggs that became a raccoon’s snack a few nights ago. Don’t worry. The pair is safe and sound and has plenty of time to attempt a second nest.

As I mentioned a few posts ago, the Loon Project is expanding into Minnesota, the state that contains more breeding loons than any other. Of course, our plan to establish a second study area 200 miles west of the current one in Wisconsin is ambitious. So I have enlisted the help of five LP veterans to help us cover our sprawling study area. These sturdy souls include Gabby and Linda, who are keeping track of our Wisconsin birds until the bulk of the team members arrive in a week, and Kristin, who, joined by new team member Katy, is taking our first look at the Minnesota study population. All of these folks have really stepped up for the Project.

Early-season work is both arduous and exciting. Arduous because we have so many loon pairs to visit. Arduous because these now hundreds of pairs must be visited one at a time and each pair member observed until we are confident we know its identity. But also exciting because we have not seen these birds since the previous summer, if at all. During the fall, winter, and spring periods, many of our loons have died or been evicted by younger rivals. And many of these young upstarts are birds we banded as chicks five to ten years ago on adjacent lakes.

Minnesota is a whole different ballgame. When we decided to take on the task of starting a new study population on the lakes in and around Crosslake, we knew that we were making a pledge to cover brand new lakes whose loons were abundant but little known. We also understood that, unlike our breeding pairs in Wisconsin, most of the Minnesota loons defended territories on the massive Whitefish Chain, where our protocol of dropping solo canoes in at boat landings and paddling to the birds was unworkable. In short, we were pledging to take on a new study population that required a completely different mode of research.

I couldn’t wait to get started. Though tethered to my instructional responsibilities in California, I gazed at these unknown Minnesota lakes on Google Earth and felt my excitement build. I collected what information I could about the lakes and loons from folks in the area. I studied maps of loon activity and banding logs provided by Kevin Kenow of USGS, who captured and marked a few dozen birds on the Chain five to six years ago and generously shared his knowledge and data. And I scratched my head.

Since I was out of commission, I needed to find someone with great knowledge of loons and a willingness to confront the daunting challenge of making our first visit to the Chain. I told Kristin that I needed her to: 1) visit an unknown study area, 2) census dozens of unknown pairs, most of which would be unmarked, 3) travel by large motorboat on an unfamiliar lake with tricky wave and wind conditions, 4) work out all of the logistics of this work with a group of unfamiliar (but enthusiastic) Minnesotans, and 5) get permission from her advisor to suspend her Ph.D. preparation and take on the project at all. I am not sure how I managed to ask her with a straight face. Predictably, though, Kristin’s response was: “Oh – that would be a blast!”. And so Kristin has begun this crucial reconnaissance. Joined

Kristin and Katy study a map of the Chain before setting out to find loons.
One of the ten nests found by Kristin and Katy on the Whitefish Chain.

by Katy, a new LP team member who is fluent in the local dialect and has turned out to be a quick study, Kristin has now covered all but a few nooks and crannies of the Chain. As of this writing, K and K have found 45 breeding pairs on the Chain and ten active nests, like the one shown above. Most of the pairs are unmarked, but they report 14 of Kevin’s banded adults are still on territory. (These marked individuals will be most valuable, as they will permit us to make preliminary estimates of territory eviction and survival for the new study population.) K and K will wrap up their coverage of the big water today, they say, and spend the next few days visiting small lakes adjacent to Whitefish. These small

Katy attempting to ID a loon.

lake visits will no doubt bring a tear to Kristin’s eye, as they will recall the work she used to do back in the Wisconsin study area.

By starting before sunrise, Kristin and Katy made the most of windless conditions.

Kristin and Katy’s effort to establish a foundation for our Minnesota work epitomizes the work of the Loon Project. We pride ourselves in carrying out research that is uncomfortable and physically-demanding, yet also exacting and painstaking. We tackle research questions that most others deem inaccessible. The work just seems too difficult, our study animals too recalcitrant. How can one accumulate sufficient data to test hypotheses about animal behavior and ecology under these conditions?

One of the 14 banded loons found on the Chain.

I was on pins and needles. Gabby had moved steadily northward and westward in her censusing of our study lakes. She started in Rhinelander. This from her datasheet Thursday:

Mildred:

  1. O/Ts, W/S (O & left leg double confirmed)
  2. Unb, Unb (both legs double confirmed)

Maud:

  1. P/S, G/G (P & left leg double confirmed)
  2. Unb, Unb (both legs double confirmed)

Coon:

  1. Ronly, Bs/S (both legs double confirmed)
  2. Unb, Unb (almost positive it’s unbanded – never saw its legs out of water, but had many chances to see bands in good light underwater if there were any present)
  3. Intruder = Y/Y, Bs/S (both legs double confirmed). Interacted with pair for 10 minutes.

Ole:
No loons

Soo:

  1. M/S, W/B (both legs double confirmed)
  2. Bs/M, Mb/S (right leg and Mb double confirmed)

At the rate she was covering lakes, I gauged that Gabby would get to Upper Kaubashine on the 3rd, 4th, or 5th. I almost asked her to jump ahead to Upper Kaubashine, but I did not want to kill her momentum. But it was hard to wait and see whether the oldest known loon in Wisconsin, thirty-three-year-old “Red-Green”, had returned to her breeding territory.

When Gabby’s report came, it was not what I had expected:

Upper Kaubashine
Sooo the good news is I found the male (Cc&S, G/G – all confirmed) and that old female (S/Y, R/G – all confirmed). The bad news is the old female may have met the end of her tenure and potentially her demise at the hands (wings??) of an Unb, Unb (confirmed) intruder who was on the lake interacting with the pair when I arrived. I witnessed a VICIOUS 12 minute battle between the female and the UNB where they were latched onto each other’s throats and beating each other with their wings (both were covered in blood) for about 8 minutes, until the old female started fleeing underwater. But the UNB was relentless and pursued her, beating her the whole way. Then the old female finally made it to little islet and looked like she was trying to find a place to go on shore, but ended up being trapped against the islet while the UNB continued to stab her with her beak and beat her. The old female finally gave out a two note wail and then the UNB finally stopped and left to go preen elsewhere. I thought the old female could be dead already, but when I left her at the shoreline she was still turning her head. I hope she can hide long enough to recover to get off the lake, but the way she was being attacked, it did not look good.

Although we have studied them for decades and know their behavior well, we find it freshly shocking to watch loons battle. The brawl that Gabby describes was more violent than any of the few dozen or so that I have seen over the years. Despite the whipping of wings and jabbing of bills that these fights entail, one almost never sees blood. However, what began as a stereotypical head-grasping and wing-beating contest, she reports, quickly morphed into an all-out struggle for survival — once resident Red-Green recognized that she was overmatched and her goal changed to self-preservation.

Physical features of a lake can play a role in territorial battles. In fact, a lake’s shape, size, clarity, and peninsulas and islands often determine whether a fleeing bird eludes its victorious opponent and flies off to a nearby lake to lick its wounds or fails to do so, suffers repeated pummeling, and ultimately dies on the lake it used to own. After the Upper Kaubashine battle, the clarity of the lake water made it simpler for Red-Green’s pursuer to track her underwater, complicating her efforts to reach safety. Thoroughly defeated but unable to elude her opponent, Red-Green was ultimately pinned against the long peninsula near the southern end of the lake, as Gabby describes.

We have no idea how Red-Green managed to escape the unbanded female’s grasp. What we do know, thanks to Linda’s visit to Upper Kaubashine today, is that, despite her dire circumstances two days ago, Red-Green is still alive. Linda was relieved to find her hugging the shoreline — as her photo shows — and skulking about under piers at the north end, while the male and his new mate cavorted far to the southwest in the protected nesting bay. Though clearly beaten up, Red-Green seems safe for the time being. Indeed, maybe she will emulate thirty-one year-old White-Yellow, a long-time breeder on West Horsehead. Evicted in 2019 after breeding on one lake for a quarter century, White-Yellow resurfaced this spring as the new breeding female on productive Little Bearskin Lake. In their tireless efforts to cope with defeat, bounce back, and resume productive lives, Red-Green and White-Yellow exemplify the dogged tenacity of female loons.

Although I am stuck in California teaching for another few weeks, others have been hitting the lakes. Based on thirty or so lakes from which I have had reports — mostly Linda’s work, but also a few lake residents — we have an early read on the return rate of adult loons from last year.

Let me explain. April and May are exciting months for the Loon Project, because we hustle from lake to lake to see which of our banded adults have returned and which have not. In a typical year, the vast majority of our study animals have managed to survive the winter, navigate fall and spring migrations successfully, and take possession of the territories they occupied the previous year. The figure hovers around 80 to 90%. A high rate of annual survival is vital to our population. The low reproductive rate of loons is sufficient to sustain the population only because most adults survive each year.

During years when I am able to steal away from my pedagogical commitments, I find these “censusing” visits oddly thrilling. On my first lake visit of the year, I fancy that the male and female both pause for a moment, wheel in my direction, and think, “Where’s he been?” This might not be pure imagination; after all, I have been observing most of these individuals for a decade or more.

Last year seemed an exception to the typical high rate of adult return. Fully a quarter of the adults that we left behind safe and sound in the early fall of 2019 failed to come back in the spring of 2020. While some of these adults had merely been evicted from their territories, most were dead. Coupled with our recent finding of population decline in northern Wisconsin, the low 2020 return rate weighed on my mind last spring. On the other hand, return rates bounce around. So I tried to avoid jumping to the conclusion that adult survival was going downhill.

Recent reports from the lakes this year have placed concerns about adult survival front and center again. Each of Linda’s almost-daily census visits seems to bring fresh news about a missing adult or breeding pair. Early on, Linda reported that a new male had replaced the long-time resident male on Manson. Okay, that happens, I thought. Nothing to worry about. The Deer Lake female, freshly marked in 2020, also turned up missing. A Halfmoon Lake visit brought no better news; the 2020 female from there was gone as well. Hildebrandt and Julia, always occupied by pairs and frequent chick producers, were vacant. Linda’s trip to Nokomis Lake was most devastating of all. Towards the eastern end of the lake, both members of a long-term pair with a consistent record for rearing chicks were AWOL. And Linda turned up only one unmarked loon from the entire 2200-acre Nokomis flowage, which usually supports three breeding pairs.

He did not know it, but Al from West Horsehead produced the straw that broke the camel’s back. His report from this morning that the 8-year-old West Horsehead male had been replaced by a 6-year-old male from neighboring East Horsehead hit me especially hard. The sample had become large enough that I could not longer deny the pattern. Looking at the number of returns right now, we have found only 21 of 31 adult loons that should be on territory. Now, we will track down some of these missing birds. A few will be alive and breeding on a seldom-visited lake near their old territory. And that will give us a momentary lift. But an adult return percentage in the low-70s, as we are seeing for the second straight year, will not sustain our breeding population for long.