loon team

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I am a nervous traveller. The day before I am scheduled to leave, I start to worry what could go wrong. Could I miss my flight? What personal items will I forget to pack? Which tasks on my to-do list will I leave unfinished?

So it was two days ago as I drove from the house where I had been staying to meet up with my Minnesota field team before flying home to California. I had spent the morning collecting data on territorial loon pairs — six on Ossawinnamakee, and one each on Fawn and Pig Lake. I relish every moment spent with loons, especially when I am on my own. But anxiety about getting my field work done, entering my data, and tidying up the place before my departure gnawed at me all day.

I tried to work backwards. Arrive at Brainerd Airport at 5:15, so leave from storage box at 4:30. Be at storage box by 4:00 to pack up canoes and check banding supplies for next month. Arrive at tech’s lodging by 2:30 to review field procedures and check in before my trip. Finish entering data in online database by 1:30. Tidy up lodging by 1pm. Leave my last study lake by noon.

When I set off to visit my techs on Ossie, I was still on schedule. As I began to round the hairpin curve on County Road 39 next to the Ossie boat landing, I thought: I just might make my flight. In a brain-staggering moment, though, I spotted an adult loon sitting on the shoulder on the east side of the highway displaying a clear intention to cross. “Oh no!”, I screamed, as I pulled to the side of the road and flicked on my emergency flashers. I ran across the highway and placed myself in the middle of the northbound lane, intending to block any traffic from passing close to the loon. As I crept cautiously toward this adult, I noticed two newly-hatched chicks huddling against it, trying to shield themselves from my view. “Oh no!”, I repeated.

Despite my shock at the loons’ predicament, I understood immediately what was happening. Six hours earlier Keith and Dawn Kellen had given me a tour of the six breeding pairs on Ossie. The Ossie-Muskie Bay pair had stumped us all spring. The Kellens had seen them together early in the year, had seen only one out on the water on multiple occasions thereafter, and yet neither they in their pontoon nor my team in our canoe could find a nest in the far east bay of the lake, adjacent to County 39. The pair had simply vanished. The sudden appearance of an adult and two small chicks told me that they had not nested on Ossie, where we had been looking for them, but on Rat Lake,

Location on County Road 39 where I found the adult male and two small chicks.

across the highway from Ossie’s eastern end. Thus, the Muskie Bay pair was in the awkward situation of seeking to nest on one lake and raise their chicks on another. That ambitious plan set them up for a difficult land crossing.

I had stumbled upon the loon family at the most dangerous point of their overland journey. The adult wailed and tremoloed as I stood in the highway 30 feet away. A southbound car and truck slowed down to rubberneck but continued by despite my frantic waving for help. My mind raced. I could not handle all three loons. If I picked up the adult, its flailing might injure the tiny chicks. Furthermore, the chicks might decide to strike out on their own across the road without their parent to guard them. I was not sure that I could discourage them from putting themselves in harm’s way while holding the adult.

Knowing that the field techs were a few minutes away, I pulled out my phone. “Call Owen”, I demanded of Siri. Owen answered in his calm baritone. But I screeched, “Drop everything and come to the Ossie boat landing. There is a loon here in the road, and I need your help!”. “On my way”, he responded.

While I waited for Owen, more southbound vehicles came by, each carrying a driver wearing a puzzled expression. But no one stopped. As I was debating the odds of getting help from a stranger, the panicked adult abruptly turned, lined himself up with the roadway, and began to run down the highway with wings flapping, leaving his chicks with me. I watched and listened in horror as his feet repeatedly thwacked against the hard pavement during this takeoff attempt and was relieved when he aborted it and skidded to a stop about 40 yards away in the southbound lane.

At that desperate moment, Mitch Carlson arrived in his pickup with his friend, Leo, and stopped in front of the grounded adult. Sensing that the window to save the loon family was closing, I scooped up the tiny chicks and marched hastily in Mitch’s direction (see photo below). He opened his door and looked at me questioningly. “Can you take the chicks?” I asked. “Okay”, he replied quickly, sensing my urgency and smoothly accepting them. He volunteered, “My wife raises chickens!”. I turned my attention to the adult in the road.

After his aborted takeoff attempt, the male loon sits in the southbound lane of County 39 while I approach carrying his chicks. Photo by Mindy Schenck.

Quick, decisive action yields the best results when capturing animals, I have found. When I drew close enough, I lunged at the rearing adult and managed to grasp it. I then folded its wings against its body, held it to my side, and did my best to fend off its bill. Meanwhile, Owen had arrived. I struggled towards the boat landing with him guiding me. Mitch followed with the chicks, while Leo walked alongside, gawking and snapping photos.

The chicks were so small that I was afraid the adult might leave them behind in its haste to put distance between us and himself after release. So I asked Mitch to let the chicks go, waited a moment, and gently

Mitch holds the two newly-hatched chicks moments before we release them at the Ossie boat landing. Photo by Leo Carner.

lowered the adult — which felt like a male based on size and ornery demeanor — into the water at the end of the boat landing. Fortunately, he dove, surfaced quickly, spotted the chicks, and promptly resumed his parenting responsibilities. It was an ample reward for Mitch and me to see them all together so quickly again in the middle of the lake.

The male and chicks reunited quickly after we let them go off of the Ossie boat landing. Photo by Leo Carner.

I will always be a nervous traveler. I do not think one outgrows that. And I need to put a schedule together to convince myself that I can meet a deadline. But perhaps on my next trip I will remember to include 30 minutes of wiggle room for unforeseen events.

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Last year I reported precocious territorial behavior by one two-year-old in Wisconsin and another two-year-old in Minnesota. These sightings were extraordinary. Before 2023, we had no record of an adult loon younger than four years of age holding or attempting to hold a territory. Naturally we were excited to see whether those youngsters would return at age three and continue to show assertive territorial behavior well ahead of schedule.

We were not disappointed.* “Junior”, as I reported recently, is firmly ensconced on the Oneida-West territory in our Wisconsin Study Area. Meanwhile, the now three-year-old who seemed determined to settle on Pig Lake on the Whitefish Chain last July appears to have claimed the Ossawinnamakee-Boozer’s Bay territory…..and is nesting! This young Minnesota male** was hatched in 2021 by the Ossie-Muskie Bay pair. So he has settled only a few miles from the territory on which he was raised three years ago.

It is cool to see two loons in different states set the record for youngest territorial breeder simultaneously. This finding suggests that all adult-plumaged loons, even very young ones, are capable of breeding. The result also implies that many young adults would settle and breed if the habitat were not already occupied by older loons.

Could it be just a wild coincidence that two such unlikely settlements transpired at the same time? Yes, it could be. As someone whose job it is to look for patterns, though, I think I see the beginning of one here. We know from past work in Wisconsin that four, five, and six year-old adults are bigger, stronger, and more competitive for breeding territories than two and three year-olds. We know also that the pool of four to six-year olds looking for territories has become depleted by poor breeding success over the past decade. In other words, fewer chicks fledged has led to fewer young competitors scoping out territories to claim. The sudden settlement of two very young adults in Wisconsin and Minnesota suggests that territorial competition has softened to the point that two- and three-year-olds can now compete for and claim territories.

So the excitement of watching territory settlement by very young adults is tempered by the nagging concern that these events are further evidence of a downturn in the breeding population. But maybe I am overthinking it. For now, let’s savor the spectacle!***

* These cool findings are not mine. Hayden and Claudia, our scouts in Wisconsin and Minnesota, found and ID’d each of these adults on territory. Kudos to these two outstanding field workers, who have braved cold, damp conditions to ID returning breeders in both states!

** I initially called this bird a female on the basis of size. It seems I was wrong. Its settlement so near its natal territory makes the loon almost certain to be a male.

*** The featured photo above is by Claudia Kodsuntie, who scouted our study lakes in Minnesota. It pictures the hind 3/4 of the 3-year-old adult on Ossie-Boozer’s Bay. The photo is not beautiful. I like it, though. It shows the kind of quick underwater view of colored leg bands that one often gets during the early census period. So it gives you a good idea of the challenges that Claudia and Hayden have oversome to make this blog post possible.

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I left you hanging last July. A young adult male in Wisconsin seemed on the brink of achieving two spectacular firsts for our long term study. He was attempting to settle at the age of two, two years younger than any male or female loon had ever settled. And he was making a play to claim his natal lake as a breeding site, which we have never observed. In the end, his effort fell short. “Gs/C,Y/S” — whom Linda calls “Junior” because he is the son of Clune, the long-time male on her lake — could not sustain his hold on Muskellunge Lake. For a time, he fell off our radar.*

But the Loon Project scout for Wisconsin this year, Hayden**, found Junior — now all of three years old — on Oneida-West earlier this week. (Oneida Lake is just over 7 miles from Muskellunge Lake, Junior’s natal lake.) Junior has not been idle. He has paired with one of our best-known females, “Silver/Blue,Orange-dot over Orange-dot”. Let’s call her “Dot”.

Dot is the second oldest adult loon in the Wisconsin Study Area and an accomplished breeder. She was banded in 1997 on the Oneida-East territory, where she reared 22 chicks to adulthood between 1997 and 2013 with two different males. Dot was evicted from Oneida-East in 2013, but that did not stop her. She moved around a bend in the lake to the Oneida-West territory. Between 2014 and 2020, she raised 3 more chicks to fledging with two different males on Oneida-West. In 2021 she again lost her breeding position to a younger female. I thought we had seen the last of Dot. But female loons are nothing if not resilient, and Dot was not ready to quit.

We are not sure what to expect from this unlikely pairing. Three-year-old Junior would shatter all records by merely building a nest and beginning to incubate eggs. And 31-year-old Dot is astounding us simply by remaining in the game. We have never seen such an inexperienced male pair with such an accomplished female. Whatever happens from this lopsided pairing will be a surprise. I guess this is why I continue to study loons.

*The featured photo is by Linda Grenzer. It shows Junior on her lake back in June of last year.

**Hayden is doing his own impression of Junior. Although he knows Oneida County well, Hayden is new to loon field work and ID’ing loons from leg bands. Not a problem! Hayden is sweeping efficiently across the study area, identifying territorial adults like a seasoned pro. If you see him out on your lake in his canoe, give him a pat on the back for his incredible efforts this spring!

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A few years ago, a non-scientist collaborator of mine suggested that I place transmitters on loons. This was a cool idea in many respects. Transmitters would permit us to monitor loons’ locations in real time and share those data with the public on a splashy website. I agreed that the technique would be thrilling and draw lots of public interest. But when the surge of adrenaline subsided, I was left with two troubling questions. First, what scientific hypothesis could we test with transmitters? Second, how would attaching transmitters to loons help us conserve loon populations in the Upper Midwest?

I am not knocking the technique. Transmitters are a potent tool used by animal ecologists to learn about patterns of migration, dispersal, and nomadism. Kevin Kenow and his collaborators employed satellite transmitters to show that typical adult loons breeding in Wisconsin and Minnesota spend the fall on Lake Michigan before heading south for winter. Kevin’s team also learned that juveniles remain on or near their natal lakes until late November, at which time they make a beeline for their winter quarters. So transmitters have helped us pinpoint times and places that are crucial to the annual survival of Upper Midwest loons. At present, though, there is no burning question concerning loons that transmitters might address.

What questions are most pressing with respect to Upper Midwest loons? With another year behind us and the 2024 field season looming, let’s take stock. How healthy is the population of loons in the Upper Midwest? And how can we best use our resources to protect them?**

Population Surveys

Two broad censuses carried out by armies of volunteers look at loon populations across large swaths of Minnesota and Wisconsin during late July. These counts are prone to fluctuations caused by changes in personnel and weather conditions during a narrow window of data collection. Still, they provide valuable large-scale “snapshots” that, in the long run, tell us how each population is faring. Furthermore, by comparing Minnesota and Wisconsin snapshots side by side, we might discern a broader regional trend.

Wisconsin’s LoonWatch survey has been carried out every five years since 1976. The survey showed robust statewide gains in loon numbers during the 1980s, 1990s, and 2000s. The most recent survey, however, revealed a decline in the Wisconsin loon population between 2015 and 2020. (The next survey will occur in July 2025.)

The Minnesota Loon Monitoring Program generates data annually and is based on six “index” areas. The enhanced geographic dimension to the MLMP survey suits Minnesota’s loon population, which is three times the size of Wisconsin’s. From 1994 to 2010, populations in two of six areas increased, two declined, and two were stable. But trends have shifted downwards in recent years. Since 2010, two areas have been stable, two have declined slightly, and two have fallen sharply. Surprisingly, the strongest, most consistent declines have occurred in the two most northerly areas (Cook/Lake and Itaska).

If we stitch Minnesota and Wisconsin surveys together, we can see that the Upper Midwest loon population as a whole increased (Wisconsin) or remained stable (Minnesota) during the 1990s and 2000s. We can also detect an apparent decline across the region that began in about 2010 in Minnesota and five years later in Wisconsin.

Poor Breeding Appears to Explain the Wisconsin Decline

Our breeding data from Wisconsin shed light on the recent population decline there. During the 1990s and 2000s, Wisconsin breeders raised healthy chicks with high survival. Brood size was split 50/50 between one- and two-chick broods. Beginning in 2010, however, chick survival and mass fell, and only 20 to 30% of broods contained two chicks. Furthermore, young adult survival plunged by 60% in Wisconsin from 2000 to 2015. Thus, poor breeding success and loss of young adults seem to be driving the population decline. There are simply not enough young loons being produced to replace adults that die.

Wait a minute. The breeding decline began around 2010, whereas the population did not begin to fall until after 2015. Are these results consistent? Indeed they are. Most loons do not settle on territories until they are five to ten years old. Therefore, several years must pass before poor breeding success is “felt” in the adult population. Hence, a statewide population decline beginning in about 2015 is what we would expect from a reproductive downturn 5-10 years earlier.

Hints of a Similar Pattern in Minnesota

We have only three years of detailed breeding data from the Minnesota Study Area. These data are too few to make robust comparisons with population trends from the MLMP. Still, we can report two preliminary patterns from the state. First, the adult return rate in Minnesota (80 to 83%) has consistently run 5% below that in Wisconsin.* Second, 31% of all fledged broods in our Minnesota Study Area from 2021 to 2023 contained two chicks. This number puts Minnesota in line with Wisconsin, where the paucity of two-chick broods reflects challenges faced by breeders since 2010. The 2022 MLMP report too cites reduced chick production in recent years as a potential cause for concern. At first glance, then, the loon population in Minnesota seems to be facing the same difficulty as its neighbor to the east.

Environmental Causes of the Decline

Thus, the loon population across the entire Upper Midwest seems to be in decline owing to reduced breeding success. This is vital information. But if our knowledge ended there, we would stand no chance of fixing the problem. To do so, we must identify the precise environmental factor or factors that impair loons’ ability to breed. In the past few years, of course, we have learned that decreased water clarity and increased black flies are two such factors in Wisconsin. That is a good start. However, it will improve our understanding — and strengthen any case we might wish to make for using local, state, and/or federal resources to mitigate the problems — if we can extend these findings from Wisconsin to Minnesota.

The Plan for 2024

2024 is going to be a pivotal year for the Loon Project. Why “pivotal”? Because we have built a conceptual and logistical platform in Wisconsin for understanding the entire Upper Midwest loon population. And we have painted a clear picture of a declining Wisconsin population and its causes. In 2024 we must pivot towards Minnesota.

Thanks to the hard work of our field crews, seed money from the National Loon Center, and the growing ranks of folks in Minnesota, Wisconsin and elsewhere who support our work logistically and financially, we have spent three productive years in Minnesota. We have identified 115 territories in Crow Wing and Cass counties that constitute our Minnesota Study Area and marked adults in about 3/4 of these territories. Our task now is to place a large enough team in the field to collect high-quality breeding data from our new Minnesota study lakes.

We will use methods in Minnesota that have proved successful in Wisconsin since 1993. In the spring we will clear cobwebs from our canoes, head to our 115 study lakes, and confirm the return or non-return of each pair member. On subsequent weekly visits single team members will locate and identify each pair member and document their nesting status or number of chicks. Most critical to our effort will be recording causes of nest failure and chick loss, because, of course, poor breeding success is the root cause of the Upper Midwest population decline.

Our growing sample of survival data from adult return rates will allow us to build a population model for the Minnesota Study Area. In addition, accumulating return records will allow us to determine whether the curiously high annual mortality of Minnesota adults that we have measured by three separate means holds up over time. If so, we will try hard to identify the source of the mortality, which would be very costly to the population.

Following the field season, we will determine whether the low breeding success in our Minnesota Study Area persisted in 2024. Then we will turn our attention to environmental factors that are causing nest failure and/or loss of chicks in Minnesota. That is, we will follow up our increased field effort with a statistical search for likely causes — especially water clarity, black fly populations, and weather patterns — that might be driving a breeding decline. It will likely take several years of intense field work to get a clear picture of such causes.

Support for Our Low Tech Approach

As you have surmised, our future promises to be unglamorous and low tech. We will not use drones, satellite transmitters, amphibious vehicles, or hovercraft to collect data. Instead, trained observers will employ the field techniques that have gotten us where we are today. We will carry our canoes to boat landings, put paddles in the water, find loons, and collect as much data as grit and elbow grease allow.

Now I am asking for your help as we do this important work to save loons in the Upper Midwest. If you believe in our work and wish for it to continue, please consider a tax-deductible donation to support us. In keeping with our theme of simplicity, we run a lean operation. None of our funding goes into the pockets of senior researchers. This year we will use our funds to support: 1) field interns who visit study lakes by canoe and collect data (about $6,000 for each of four interns covers a monthly stipend and reimbursement for gas); 2) lodging for the interns and myself (about $10,000, if recent experience is a useful guide); 3) economy airfare for me to make two trips to and from the Upper Midwest and gasoline for the motorboat we use to cover breeding pairs on the Whitefish Chain ($1800); and 4) color bands for marking loons and costs to replace broken equipment and needed supplies ($4,000). So I estimate our need to be about $40,000 for the expanded 2024 field effort in Minnesota.

By the way, we currently have enough funding in place to support a modest field effort in Wisconsin. However, increased funds directed to Wisconsin would also strengthen our effort in this most valuable long-term study population. You may earmark your donation to go towards our Wisconsin work, if you so choose.

You may use this link to go to our “Donate” page. Thanks for any support you can give us. We promise to make every penny count! 

The Future

Our future prospects seem bright. In addition to cultivating a large number of supporters across the Upper Midwest, we are forming an Upper Midwest research team. Obtaining funding is always uncertain, but our new collaborators have a good track record of acquiring major regional funding. We will apply for such funding this year and, if we are fortunate, might receive it by late 2025.

If all goes well, lake dwellers in Crow Wing and Cass counties will soon get used to the same peculiar sight to which lake residents in Oneida and Lincoln counties have become accustomed: paddlers in solo canoes, wearing bleached PFDs and binoculars, scanning the lake’s surface ceaselessly for loons.

FOOTNOTES

* This pattern is enigmatic. I can think of no reason why Minnesota loons should die at a higher rate than Wisconsin loons. One hypothesis is that the pattern is the higher density of loons in the Minnesota Study Area than the Wisconsin Study Area results in greater competition for territories in Minnesota. If so, what appears to be a low adult survival rate might instead be a higher rate of eviction. From a conservation standpoint, we must hope that eviction explains the apparent difference. If Minnesota loons truly die at a substantially higher rate than Wisconsin loons, Minnesota birds would have to offset that mortality rate with considerably higher breeding success.

** The beautiful featured photo, as usual, is by Linda Grenzer. It shows a foot waggle by two-year-old male that tried to claim her lake as its territory this past summer. We are slightly worried that this youngest-ever settler is a sign of population decline in Wisconsin, because four-, five-, and six-year-old nonbreeders would normally outcompete it for this territorial opening.

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I awaken bleary-eyed after two hours of deep sleep and three hours of tossing and turning. It is time to get up, grab a banana and coffee, choke down my usual peanut butter sandwich, and face the day. I wrap a flannel shirt around my waist — smiling as I recall how my daughter would tsk-tsk at the sight of me — and walk unsteadily down from my fleabag motel in Breezy Point to the convenience store/gas station at the highway intersection where I eat my meals. My whole body aches from lifting and carrying two motorboats in and out of small lakes. My knees are skinned and bruised from squatting for hours on metal boat seats. My hands bear dozens of small nicks and cuts — this one from the Nelson Lake female, this one from the Pelican-Breezy Point chick, this one from nipping myself with needle-nose pliers when closing a steel band on the Star Lake male. My nails are thickly encrusted with the plastic glue we use to seal the bands.

Exhausted and beaten up as I am, I become obsessed with not making a mistake on my trip home. “Don’t forget the blood drops and feather samples. Don’t forget to return the motel room key. Don’t run into a curb and damage the rental car. Don’t leave your laptop in the trunk at the Brainerd Airport. Don’t lose your boarding pass. Don’t forget to text Linda and ask if she can help Molly stow the Loonmobile in Wisconsin.”

I make it to the Brainerd Airport. The Delta ticket agent kindly and somewhat inexplicably checks both of my bulky suitcases for free (!). My Pre-Check status does not show on the boarding passes he prints out for me, though, so I am forced to wait in the security line as passenger after passenger is guided through ahead of me. But at last I am in my seat on the plane. The hardest part of this travel day is over.

At brief moments, I reflect on the past three weeks of loon capture. While most teams have fixed roles for each team member — e.g. Martha runs the motorboat, Steve spotlights the loons, Kevin handles the netting, Emma prepares the bands and data sheet on shore — we use a “musical chairs” model, so that each intern gets a chance to play each role. (The exception is netting, which is tricky to learn and which would cost us many captures during the learning process.) Because of our quirky approach, I as netter am working with a different spot-lighter and different motorboat operator on each lake. This means that I am constantly coaching, constantly adjusting to different spotlighting and boating styles, and all the while just hoping to catch the birds. “Keep the light right in his eyes!”, I whisper. “Lean way forward so that you don’t spotlight the bow!” “Angle the light higher on the water so we can see the loon if it surfaces at a distance!” “Quickly and broadly”, I bleat, after a loon dives right next to the boat, because such a bird could resurface in any direction but will likely be close at hand and easy to see when it does so. “Stay on him!” I cry, helpfully, when a chick dives and swims away but remains within a foot of the surface so that we can track it and pounce when it comes up. Our odds of capture seem long for each loon we spot. Yet somehow, despite our inefficient and high-stress rotation of roles, we manage to catch most of the loons we find. The interns, I learn again this year, pick up each role quickly. They and I are pleased by their rapid improvement. I hope they forgive my occasional impatience during the hunt for each loon. I tell them, “Great work, everybody!” and give an occasional fist bump, when we net a particularly evasive individual. Considering the steep learning curve, they do an amazing job.

In fact, capture went well in both Wisconsin and Minnesota. In large part because of the generous help of Kevin Kenow and his USGS banding crew that spent six nights out, we caught and banded more loons in 2022 than we have in any other year: 94 individuals in Wisconsin and 95 in Minnesota. (Kudos and thanks also to Mike of the National Loon Center and Terri and Richard, NLC volunteers.) We collected crucial mass data from our loons in both states. Comparison of these masses with past years — and with water clarity data from Landsat satellites — might be enough to tell us if Minnesota loons, like Wisconsin loons, have suffered weight losses over the past quarter century owing to declines in lake clarity related to increased rainfall.

We have now caught enough loons in north-central Minnesota that our Minnesota Study Area has taken shape. It includes Nisswa and Pequot Lakes to the southwest, the Whitefish Chain to the north, extends in a northeasterly direction to Outing and Emily, and ends at about the hamlet of Mission to the southeast. In all, the new Minnesota study area comprises some 110 territories. These territories will be those we use to gauge the status of the loon population in north-central Minnesota. These territories will tell us whether Minnesota loons face the same dangers that loons in northern Wisconsin do. I have seen enough similarities between my two study areas that I am concerned. But we must wait to see what the data show.

So as I scrape glue off my nails, rub my sore knees, inspect the healing lacerations on my hands and forearms, and take deep breaths to try to clear my fuzzy brain, I smile. We did well this year. We are well on the road towards assessing the status of loons across the Upper Midwest. And I love my job.

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Sometimes during a night of capture, when we have finished color-banding a loon and are releasing it back into its territory with its family members, I say to the bird, half jokingly, “Welcome to the Loon Project”. But I mean it. Once we place colored leg bands on a loon, we start to feel a kinship with that loon and take an active interest in its well-being.

The bond we feel with each banded loon grows as team members report its trials and tribulations across many years of its life. “Red over blue-stripe on Lumen is soooo tame!”. “Omigosh, that female on Lumen was super aggressive when two intruders landed in her territory this morning”. “Red over blue-stripe really scared a kayaker that came too close to its chicks today”. “Red over blue-stripe fed its chicks 58 times during the hour I was observing the family; those chicks begged relentlessly.” “Red over blue-stripe just skulked around the southern end of the lake this morning while her mate foraged with a new unbanded female. She looked so bummed out.” “There is a new breeding female on Birch today; she is red over blue-stripe!”

Just as we mourn when a male or female is evicted from its territory by a young adult, we cheer when it bounces back and claims a new territory nearby with a new mate. If one of “our” loons should be injured by a lure or fishing line, we spring into action to save it.

Knowing and caring about our study animals makes it more enjoyable and rewarding to observe them. But the warmth and connection we feel towards our loons is really just a pleasant byproduct of a coldly pragmatic research philosophy: mark every loon you can, and track marked individuals obsessively throughout their lives.

Why are we so fixated on marking loons and studying marked individuals? Because marking and reobservation allows us to turn anecdote into science. If one watches five unmarked adult loons circling and diving together in early July on Brandy Lake, and two of the five birds yodel at each other, one might conclude that two members of the group must be males that became aggressive for some reason. If, on the other hand, the five loons are color-banded, we can begin to make inferences about behavior. We might observe that the group consists of two territorial pair members from Brandy and three intruders: a 3-year-old male floater reared on Johnson Lake, a 7-year-old male floater raised on Bullhead, and an 11-year-old female breeder from neighboring Arrowhead Lake. We might further note that the two yodelers are the 9-year-old territorial male and the Bullhead floater. And finally, we might observe that the 3-year-old and neighboring female fled from the group of 5 following the yodeling incident and flew off shortly afterwards, while the 7-year-old male engaged in many simultaneous dives with the male breeder and stayed 36 more minutes before departing from the lake.*

Of course, one visit to a breeding territory does not by itself lead to any useful scientific conclusions, even when loons are marked. But when this day’s observations are combined with those by scores of other field observers on hundreds of marked loons and thousands of early mornings, statistical patterns begin to emerge. Indeed, in a paper we just published, we document how floaters (nonbreeders too young to claim a territory) behave differently as they age, how territory owners tailor their aggressive behavior to floaters of different ages, and how loon parents optimize defense of chicks differently as they grow. So the accumulation of observations on marked, well-known loons made possible several steps forward in our understanding of territorial behavior.

Marked loon populations have value over and above the strides they help us make in understanding loon behavior. Since loon numbers have clearly declined in Wisconsin in recent years and apparently also among the less-well-known loons of Minnesota, our study animals in both states suddenly have special significance. In the coming years, we hope to use our study populations in Minnesota and Wisconsin to ascertain the causes of the declines and work with others who love loons to turn things around.

*Linda’s cool photo above is of Nelson Gould, a Chapman student, who worked with us for three years.

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I am fearful of new challenges. In 1993, when I began to study the behavioral ecology of loons on a cluster of 12 Wisconsin lakes, doubt gnawed at me. How can one carry out meaningful, publishable, scientific research, if one’s study animals are large, aquatic, diving birds that range over huge territories, dive constantly, and must be followed in boats? Would my work be severely limited in scope, like that of researchers on porpoises, whales, and sea turtles? I had no training in field techniques for study of aquatic animals, only my childhood experiences paddling canoes over vast stretches of Lake Temagami in central Ontario. But my fascination with loons — which also grew during summers on Temagami — and my sense that canoes could be an effective means of tracking them without altering their behavior pushed me forward. And so, for reasons that I do not understand, I began to treat seemingly insurmountable problems with funding, logistics, and personnel as mere nuisances. And I ignored warning signals that any reasonable young scientist would have heeded. I began to study loons.

So it was in Minnesota. Although one might surmise that beginning a field project on loons in one state would be much like doing so in another, this is not so. True: loons are loons. We see many of the same behaviors, hear the same basic calls, and witness the same sorts of human-loon interactions in Minnesota that we have seen over the past 29 years in Wisconsin. But all else is new. Starting a major field study in the Crosslake area has reminded us that we have an army of friends, lake residents, and supporters in Wisconsin. These folks have housed us, fed us, carried us around in their boats at times, and — most important — provided us with a trove of information on our study animals to supplement our field data.

And our Minnesota study lakes are far larger than those in Wisconsin. Only a masochist would attempt to study loons on the massive Whitefish Chain — where about half of our Minnesota study animals reside — by canoe. So a growing list of Minnesota friends and supporters have provided us with boats — thanks, John, Mike, Mary, Keith, and Dawn! — that permit us to cover the big water. (By the way, several others have made our work possible by providing housing — thanks, Melanie, Charlie, Mary, Jim and Jon!) In fact, we have learned that we can move about far more easily on huge lakes than on the tiny lakes where most of our Wisconsin loons live. Moreover, we can hold our position in the water more effectively and work in greater comfort on the Chain, providing winds are calm.

However, loon capture is another matter. Having caught rather few loons on huge lakes in Wisconsin, I was concerned that my team would waste many hours each night scanning the dark water before our spotlight came to rest upon a tiny light smudge that would become, on approach, a loon parent and a chick that we could capture. In truth, we do spend somewhat more time searching for Minnesota loon pairs that we are accustomed to. Furthermore, locating loon families acoustically is more difficult in Minnesota, because Minnesota loons seem less vocal at night than their small-lake brethren in Wisconsin. But once located, loons in Crow Wing County have proved easier to capture. So my irrational fear that loon capture would be slower and more difficult in our new western study area was unfounded.

What progress have we made in Minnesota so far? Despite the ill-timed failure of an outboard motor that forced us to cut short our night and limp back to our boat landing using only a single canoe paddle and three tote box lids, we have marked 37

adults and chicks in four nights. We banded sixteen loons on Ossawinamakee alone last night. In a few hours’ time, five anonymous territorial loon pairs on Ossie have become a valuable set of individuals whose behaviors, life histories, and survival rates we can track to enrich our understanding of loon breeding behavior and population dynamics. Moreover, our experience in Wisconsin tells us that the brief capture and marking process leaves little or no imprint on loon behavior. Loons caught and marked one night act the next day as if the event never happened. They display the same casual indifference towards us and other humans that they showed on the day before.

On the other hand, we ourselves are greatly changed after we capture and mark loons. Marked loons are individuals to whom we are committed forever afterwards. Yes, we get scientific data from them. But marking creates a lifetime bond between observer and loon. We know these birds. We cheer as chicks we marked return as adults to the study area and claim territories. We mourn when marked parents lose a chick or abandon a nest. And we move heaven and earth to guard these individuals and come to their rescue, if they need it. It has proved impossible to maintain pure scientific indifference to our study animals.

In short, Minnesota loons are excellent study subjects. They ignore our visits to their territories and forgive us immediately after capture and marking. My initial fears and doubts about marking and observing Minnesota loons have subsided. We can now see that we will learn an immense amount about territorial behavior, breeding ecology, and population dynamics of Minnesota loons — if we are willing to shoulder the burden of an intensive field project in a new state on these most engaging birds.

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Yes, it has come to this. Chick production of breeding pairs in northern Wisconsin has declined steadily during the past quarter-century. Black fly outbreaks have made hatching success even worse in the past five years. So we are searching desperately for a positive outcome that we can greet with a sigh of relief. And we have one: breeding success has ticked slightly upwards in 2021.

I wish I could report that breeding success has rebounded with a vengeance. After a dreadful 2020, I felt that a strong rebound might be in order. But the recovery has been modest. Looking at the numbers, only three breeding pairs in our study area had chicks as of this date in 2020. That laughably low number resulted from 97% abandonment rate of May 2020 nesting attempts owing to black flies. Meanwhile 59 pairs were incubating eggs on this date in 2020. As of August of last year, 36 pairs were rearing chicks. This amounts to about 33% chick production in 2020 (36 of 110 breeding pairs). At present, we have 24 pairs in Wisconsin raising chicks and 41 other pairs still sitting on eggs. If we use the 2020 nesting outcomes to project 2021 success, we should end up this year with roughly 46 of 110 pairs with chicks in northern Wisconsin. A 42% breeding success rate is nothing to crow about. But since I am a positive person, I will choose to focus instead on the 28% increase in chick production between last and this year!

What about Minnesota? We have only just arrived in Minnesota and have no data from 2020. So we are not able to provide a very calibrated picture of breeding success in the Crosslake area, where we are located. Furthermore, Crow Wing County, where we work, is running about a week behind Wisconsin, so our data are even more preliminary in Minnesota than in Wisconsin. Still, we can already say that 2021 was a light black fly year in north-central Minnesota, as it was in northern Wisconsin. And that is a good thing. Out of 104 territorial pairs we are currently following in the Crosslake area, Jordana and Katy reported a few days ago that 13 have chicks and 42 are on nests. We estimate that the total pairs with chicks will number about 40, by the time August rolls around. But we are still scouting many of our Minnesota lakes, so that number could grow to 50.

Scouting new lakes is a tricky business, by the way. Going onto a new lake with no information on previous loon usage or breeding success forces you to read the behavior of loons on the lake to infer if those you see are: 1) an established pair that has is not currently incubating eggs, 2) a pair that hangs out together but never breeds, 3) an unpaired young floater, or 4) the “off-nest” member of a pair, whose mate is on a nest on the lake. Katy and Jordana’s daily sleuthing has been effective so far. But sometimes you misread the signs, which, in fact, can be thrilling. No doubt a few lakes where K and J found no loon or only a skittish loner on their first visit will offer a view like that in Linda’s photo on their second.

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In many recent posts, I have emphasized a certain theme: male loons begin to die off at a rapid rate after age twenty, while females linger on. Part of the reason for this contrast is the nature of territorial contests in each sex. Territorial males fight hard in attempting to hold their breeding position on a lake and commonly die in territorial battles. With rare exceptions, territorial females survive eviction from a territory, move to an unoccupied lake nearby, and resettle on a new territory when opportunity permits.

While the escalation of male territorial battles is interesting in itself, it also impacts the composition of the breeding population. Specifically, adult male loons’ propensity to die frequently in battle skews the sex ratio towards females in the breeding population.

These excess females are “floaters” — adults capable of breeding but prevented from so doing by the lack of a mate and/or a territory. Floaters are the loons that one sees living alone on small lakes, drifting about aimlessly on large lakes, and intruding into territories from time to time to confront breeders. A large proportion of the loons that gather in flotillas of five adults or more during July and August are floaters. Floaters can be thought of as “hopeful breeders”; that is, they are always ready to settle and breed with a mate and territory, if they can find one. The excess of female floaters means that there are always far more of them looking to settle and breed than there are male floaters able to pair with them. In effect, males are snapped up by females as soon as they become available for breeding.

In May of this year, we re-encountered one of our veteran breeders, “Silver over Blue, Green over Orange” (or “S/B,G/O”), whose breeding history illustrates the striking contrast between males and females brought about by male-biased mortality. S/B,G/O was first captured and marked as an adult in 1997 on Dorothy Lake, where she raised two chicks with her mate. Her mate was evicted in 2001 and died either during eviction or shortly afterwards. But she lingered on. When an opening became available in 2002, she settled and nested with a different male on Hasbrook Lake, just a few miles to the northwest. Having failed to raise chicks on Hasbrook, S/B,G/O (now at least 14 years old) evicted the female breeder on Hodstradt in 2004, paired with a third male, a six year-old, and reared four chicks there during the next three years. She followed this young male to Horsehead Lake in 2008, when he was driven off of Hodstradt, and the pair fledged 3 more chicks over the next four years on their new lake. When the male was evicted yet again in 2013, S/B,G/O traded experience for youth and found a new six year-old male as a breeding partner. We breathed a sigh of relief when she broke up with this youngster after a year together, as he was unfortunately her son from Hodstradt! Then 23+ years old, S/B,G/O again became a floater, forced to return to the breeding grounds in 2014 and 2015 with no clear prospects for breeding.

I have become attached to the birds in the study area, so I was delighted to find S/B,G/O back at Hodstradt in May of this year with her fifth recorded mate. At 26+ years of age, she is perhaps fortunate to be paired again. Her mate this time: a four year-old hatched on Clear Lake. We observed no breeding attempt by this new pair – only a small percentage of four- year-old males that settle on territories actually nest – but it is likely they will nest in 2017.

As a human, I like to think of S/B,G/O’s life as a lesson in resilience – the dogged refusal of an animal to forsake breeding despite repeated setbacks and advancing age. But, as a behavioral ecologist, I think of this female more as a striking example of how animals adapt to maximize their breeding capacity regardless of the breeding environment they face. By the way, S/B,G/O is not the only female in our study area who has continued to breed despite frequent changes of partner. S/R,O/O, another 26+ year-old from Swamp Lake that we recaptured a few nights ago (see photo with Eric), has gone through at least 5 younger mates during her 20 years of breeding there. Clearly the pairing of tough, old females with much younger males is – as my daughter says – a thing.