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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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Although it has been over a decade, I still remember that morning vividly. I was observing the banded male and unbanded female on Brown Lake as they foraged on the wide portion of the lake’s eastern side. As is the case with most of our study animals, the loons were quite tame. They reacted indifferently to my red canoe as I tracked their progress slowly down the lake.

The loon pair’s relaxed foraging seemed odd during what had been a most tumultuous year on Brown. Though the female had resided on the lake since April, three different males had vied for and held the position of male breeder for portions of the season. Ultimately, “Mint-burgundy over Silver, Green over Blue-stripe” (Mb/S,G/Bs for short) drove off his competitors and became the male breeder. Evicted from Two Sisters-West in 2008, Mb/S,G/Bs had drifted about for two years before finally seizing control on Brown. Sadly, his victory in late June 2011 came too late for successful nesting to occur. So on the day of my visit, August 3rd, Mb/S,G/Bs and his mate were merely killing time before molting and readying themselves for the southward migration.

As I watched the laid back pair forage, an intruder appeared overhead. The pair watched the intruder as it slowed, descended, and parted the water’s surface to land twenty meters away. The intruder — a female hatched and reared 15 km north on Moon Lake, near St. Germain, three years earlier — was clearly uneasy. She bowed her head, dipped her bill in the water repeatedly as she drew near the pair, and initiated many brief dives as she circled them. For their part, the male and female breeder seemed to be going through the motions. They circled slowly with the intruder and peered at her when she dove but seldom dove themselves. The video below from South Two Lake depicts a similar scenario.

Afterwards I reflected upon the encounter. More clearly than ever before it seemed to me that I was watching a jittery youngster confronting two old, confident territorial loons. I am not sure why it had taken me eighteen years to do so, but I felt that I suddenly understood something very fundamental about loon territorial behavior. Loon pairs watch the behavior of an approaching intruder closely, quickly size it up — estimating the level of threat it poses to their territorial ownership — and then behave accordingly. As a result of this particular lake visit to Brown, my research team began to recognize and record “initiates dive” behavior (i.e. being the first loon in a group to make a short dive) and also “declines dive” behavior (refusing to dive when another loon nearby has done so). These advances led to new data collection and new insights into age-related territorial behavior.

Intruders, we have learned recently, provide ample signals of their age, fighting ability, and level of interest in battling for territory ownership. As the above figure shows, one of the clearest hallmarks of youth among intruders is the “initiates dive“ behavior. Young, timid intruders with no intention of vying for territory ownership are nervous Nellies, like this three year-old female was, and carry out many initiates dives. At the same time, these youngsters almost never show the “simultaneous dive“ behavior (which signals a willingness to escalate conflict), nor do they yodel or show aggression of any kind. Without question, there are dozens of other small signals that territorial pairs pick up from intruders to assess their age and degree of threat they pose.

And territory owners act upon the information they glean from intruders. That is, they treat a harmless visitor within indifference; they behave aggressively toward a dangerous intruder. The keen ability of territory owners to distinguish between intruders helps us understand how they can survive hundreds of intrusions each year without becoming exhausted. They save energy where they can and only get worked up and aggressive when they must.

These conclusions might sound obvious and intuitive. They are. And yet it took some 20 years and dozens of statistical tests to recognize and analyze the age-related patterns in behavior that allowed us to infer how both intruders and pair members betray their motives and strategies during such encounters. Fortunately, our perseverance has been rewarded. A few days ago our paper on interactions between intruders and territory owners was accepted for publication in a good behavioral journal. It should appear in print early next year. Thus, we are incrementally closer to understanding the entire territorial system of common loons.

If you would like to support our work in understanding territorial behavior, measuring population parameters, and conserving loons in the upper Midwest, consider a donation to the Loon Project HERE. At the moment, we are hoping to buy two canoes and a small motorboat, which would allow us to continue our long-term Wisconsin research while adding new lake coverage in our new Minnesota study area in 2022. Thanks for any support you can give us!

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Many scientific journals are trying to add some color. That is, amidst the dry, highly-condensed scientific analysis and interpretation that is their standard fare, they are sprinkling lively photos and vignettes. These science tidbits vary from one journal to another in form and length. But all are much easier — and more fun — to look at than run-of-the-mill scientific articles.

In the past decade, I had observed the increasing frequency of short, splashy stories from a safe distance. Now that I have got scientific writing figured out, why should I diverge from it? (Okay….this blog is a dramatic departure from scientific writing, but I have settled into a good groove, so I do not count it!) In mulling over the possibility of a little splashy piece, I was not sure: 1) what I might write up as a colorful little story, 2) whether such vignettes are likely to be read widely, and 3) how hard it would be to get one published. So for many years I made no effort to report a loon finding in this new format.

The hypothesis of “spotlighting” by loon parents with chicks changed my mind. Having stumbled upon Frontiers in Ecology and the Environment and read a few of their delightful little photos and attached stories, I thought: “Well, I could do one of those!” I was encouraged by the fact that my current “hot” idea, the spotlighting hypothesis, is perhaps the most exciting one I have ever had. When I made statistical findings that provided strong support for the hypothesis, I was just bursting to share them with other scientists.

Sad to say, sharing of a finding or hypothesis in the form of an “Ecopic”, as Frontiers calls their little photos/stories, is not a thorough and rigorous means of sharing. 250 words is simply too few to provide evidence in support of any idea. If you are a cynic, you might even claim that Ecopics and their ilk allow scientists to get their half-baked ideas out there without thorough scrutiny by their peers. Please take my word for it when I say that rigorous testing of the spotlighting hypothesis is very much on my mind!

Ignoring for the moment that not all is nailed down with regards to the spotlighting hypothesis, take a look at the Ecopic. My text and Linda’s photo tell a story that we had not dreamed of when intensive study of loon territorial behavior began 30 years ago. So for now, let’s put aside the uncertainty and simply enjoy what loons might be doing!

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One of the challenges of studying loons is that they are so well-loved. Many people have observed them, written down notes about them, and — here’s the problem — shared their speculations about all aspects of loon biology with others. Those of us who study loons are in a position of power, because the public looks to us for information. It takes some humility, when a journalist asks us a question about loons, to admit that we do not know the answer. Admitting ignorance is embarrassing. It disappoints the questioner. It makes us feel inadequate and uninformed. Yet admitting ignorance is vital. Our willingness to say we understand fully some aspect of loon biology that we do not — on websites, at conferences and in print — poses great problems for loon science and conservation.

Wait. Published material on loons should help move our understanding forward, right? Yes and no. Well-researched, robust science on loons improves our understanding; anecdotal, speculative work based on small samples of loons, inexpertly analyzed, and passed off as fact does not. In the field of loon behavior and ecology, a huge “grey literature” exists, which consists of popular loon articles, books, websites, unpublished Master’s theses, and low-brow pseudo-science that eked its way into the lower echelons of science journals. When such sketchy information makes up the majority of the material publicly available about loons, there is a real danger that speculation and pseudo-science might drown out real science.

There is good news, however. Our understanding of loon biology is better now than ever before. Across the continent, loon researchers have started to mark individual loons, examine many aspects of their ecology and behavior, use powerful statistical tests, and publish their findings regarding loons in peer-reviewed scientific journals. This last step is critical, because peer review means that three or more scientists are criticizing a paper submitted for publication anonymously and candidly before publication. In most cases, scientists who review loon research do not themselves study loons, so they can bring an important bit of objectivity to the process and read what a loon scientist writes without preconceived notions about the species. Reviewers who are not loon researchers, in effect, are helping pull the study of loons into the mainstream of scientific research. If scientific studies on loons are treated with the same level of rigor as those on fruit flies, downy woodpeckers, wolves, elephant seals, and angelfish, loon science will eventually become as robust and reliable as science carried out on other species.

Such rigor in loon study is long overdue. Now that we see multiple populations of loons declining in number or reproductively, we must do better. We need to advance from “there are still loons on my lake, so the population is stable” to careful, longitudinal quantification of adult survival, juvenile survival, breeding success, and other demographic parameters that can contribute to a valid statistical population model.

Why does it matter? Because when we fall into that very human trap of expounding upon a topic without a foundation of scientific fact, people sometimes listen and use our pronouncements in ways that we did not foresee. Case in point: the Minnesota loon population. Any population ecologist who looks at the data — well, lack of data, in this case — will tell you the following. We truly have no idea whether the population of loons in Minnesota is rising, falling, or remaining steady. We simply have not marked adults, carefully recorded their rate of return to their territories, measured the number of chicks they have produced, marked those chicks, measured the rate at which those chicks return, and plugged all of these data into a statistical model. Without such a thoughtful, complete analysis of survival and reproductive success, any statements about the Minnesota loon population are simply speculation — speculation that could be seized by others to undermine conservation efforts. Indeed, one difficulty faced by the “Get the Lead Out Minnesota” campaign (which anyone who loves loons and wildlife should support strongly) is that there are many baseless statements to the effect that the Minnesota loon population is stable in the media and the grey literature.

So, a plea. Let’s emulate population ecologists in describing our knowledge of loon populations in Minnesota and elsewhere. Let’s apply rigorous techniques and wait until the research has run its course to reach any conclusions. In the meantime, let’s have the courage to utter those most honest but difficult few words: “We don’t know”.

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We have had an exciting last few weeks. First, our paper on population decline in northern Wisconsin has been the most frequently read paper in Condor: Ornithological Applications every single day during the past three weeks. Of course, I jinxed it, and when I looked just now I found that we have fallen and are only the second-most read paper! In any event, we seem to be getting the word out about problems that loons are facing in the Upper Midwest.

Second, Brian Hoover’s paper that describes and explains lake preferences of juvenile loons — those that have just fledged and become independent of their parents — has just come out. Brian’s paper shows that juveniles tend to visit lakes that have similar pH to their natal lakes and also that they use large lakes with a variety of fish species present. In other words, if we are to preserve the Upper Midwest loon population, we must look out not only for lakes where loons nest but also those lakes nearby where juveniles fatten themselves up to prepare for migration.

Third, our collaboration with Sarah Saunders of Audubon has borne fruit; Sarah’s paper has just been accepted by Journal of Animal Ecology and should appear as an accepted article in the next week or two. Her model, which combined measures of land use, climate, and our study population, indicates that the North Atlantic Oscillation — a fluctuating climatic pattern that is projected to increase under climate change — is having a net negative impact on both adult loon survival and chick production in northern Wisconsin. The pattern is complex, but it dovetails logically with the population trends we have seen in northern Wisconsin. The simplest interpretation of her findings is that the North Atlantic Oscillation affects food levels on the loons’ wintering grounds, which, in turn, impact survival and subsequent chick production. Sarah also found that increased human development reduced adult loon survival. Most alarmingly, Sarah’s simulations of the next decade all project decline for the northern Wisconsin population, just as our Condor paper did. So, we must look for more ways to boost loon breeding success and adult survival on the breeding grounds in an effort to counter what is a most worrisome trend.

Sarah’s findings place new urgency on my efforts to understand all 12 months that constitute a year in a loon’s life. Most recently, I have batch-plotted recoveries of loons banded in northern Wisconsin that covered distances of more than about 200 miles. As you can see from the featured image above, we have a lot of these data. (You might have to click on the title in the e-mail to see the map.) Leaving aside the small number of interesting shifts westward and northward, the photo confirms the wintering pattern that I mentioned in a recent post. Our Upper Midwest loons winter in large numbers along both coasts of Florida — especially the Gulf Coast. About a quarter of our loons, however, winter off of the Carolinas, especially North Carolina. Concerned as I am with the increased rate of mortality among adults in recent years, I cannot help thinking that hazards along these coastlines are creating trouble for them. Clearly while I can use the fall, winter, and early spring to rest and recover after intense field work during May, June, July and August, my study animals do not have that luxury.

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We have had a good week on the Loon Project. A few days ago, the November 2020 issue of Condor: Ornithological Applications came out that contains our article on the declining loon population in northern Wisconsin. Our article was selected as an “Editor’s Choice” for the issue! Linda’s photo graces the cover, and it

features Linda’s “own” loons in a touching embrace. Of course, there is brutal irony here. The article documents the fact that there are fewer and fewer two-chick broods in the Northwoods these days. Linda’s picture, therefore, displays an exception to the trend of reduced breeding success in the past quarter century.

  • Condor’s list of the articles most often read by visitors to the journal website.

Speaking of our article, as of today it is the one most frequently read by visitors to the journal’s website. I take heart to see this; maybe that means that we are getting the word out that Wisconsin’s loon population should not be taken for granted. During my optimistic moments, I hope that attention focused on the fragility of our population and its current downward trend might help us take the first easy and obvious step to help loons. What is this step? First, we must get rid of lead sinkers and jigs, which kill many Wisconsin loons each year painfully and needlessly. This requires simply having the sense of responsibility to replace all of the sinkers and jigs in our tackle boxes with lead replacements that work just as well but do not kill loons and other wildlife. If we take this simple step and — here’s the hard part — have the chutzpah to ask our friends and relatives and neighbors to do the same, we can start a wave and get it done. Are you willing to step up and do this for Wisconsin’s loons?

A second piece of good news for the Project this week was the acceptance for publication of our collaborative paper on climatic and land-use impacts hurting the northern Wisconsin loon population. As with the just-published Condor article, this accomplishment is decidedly bittersweet. While it is nice to have your work recognized as important and worthy of publication, it is a shame to see yet more scientific evidence that spells trouble for loons.

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Having just posted about our discovery that loons with chicks are in a desperate struggle to protect long-term territory ownership by hiding their own chicks and “spotlighting” neighbors’ chicks, I kept thinking: “That is pretty cool! How can I let others in science know about it?”

In looking for a suitable journal where I could submit our new paper detailing that finding, I came across the high-impact journal Frontiers in Ecology and the Environment. Our entire data paper turns out to be too long and the subject matter not appropriate for a full-length paper in Frontiers. But, while leafing through the journal, I saw that it also publishes 150- to 250-word blurbs accompanied by crisp photos that together describe an “Aha!” moment you had as an ecologist — a moment when you discovered some pattern that answered a burning question or opened up a new field of study.

That piqued my interest. Since I study the most photogenic animal on the planet and work with a talented photographer, I thought I would take a flyer, work up the nasty neighbor story, include a couple of Linda’s photos, and see what the journal said.

The writing was sheer agony. 250 words is a laughable number for explaining a tricky concept like spotlighting of neighbors’ chicks, because you have to introduce the species, explain the territorial system, describe loon chicks and their behavior, and — most challenging of all — explain the complex system of information-gathering by floaters and intrusions by territory owners that underlies the nasty neighbor story. I wore out my “delete” key writing this tiny, unbelievably dense piece.

But it was worth it. Less than 24 hours after I sent the blurb in, the editor accepted it. Linda and I are thrilled. I think my tofurkey will taste a little better this year! Sorry…..I am unable to show you the piece here because we have signed a form preventing that until publication. I promise to post a link as soon as Frontiers publishes it.

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Several months have passed since our paper on the population decline in northern Wisconsin was accepted for publication. But the wheels of science turn slowly, and only just now has the online “issue” come out that contains our article. To accompany their published articles, the journal invites authors to publish also a blog post on the journal website, and I jumped at this opportunity to spread the word about the peril that my study population now faces and its particular meaning to me.

Rather than repeating that blog post here and incurring the wrath of the journal, I will include this link. The article itself is freely accessible to the public, according to the website.

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What is better than finding out that your just-published article has been featured by an online science media outlet? Finding out from your dean! An hour ago this happened to me as I strolled out of our new science building.

We were excited to learn this article has excited some attention. It was a bit of a sleeper. Published in a good — but not spectacular — journal, our investigation of the flies’ impacts and loons’ logical responses to them caught the eye of the journal’s media department. I will not bore you by rehashing our findings, which I have discussed before. By the way, a related media blurb included Linda Grenzer’s cool photo of the male on her lake sticking on the nest in 2017 despite flies biting him mercilessly. (Another of Linda’s related photos appears above.)

Fortunately, this year has been a mild one for black flies. So while pondering the harsh negative impacts that black flies often have on loon nesting behavior and breeding success, we can all relish their absence.