human impacts

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Don’t tell me it never rains in southern California. I just spent Sunday morning getting drenched while hiding under an umbrella in Huntington Beach. My task: walk a concrete flood channel — we Californians call them “rivers” — while trying to protect my binoculars from a steady downpour and identify every soggy bird I could find along the waterway. Why would I subject myself to these miserable conditions? I was a proud participant in the Coastal Orange County Christmas Bird Count. (The photos above show: 1) me with another damp colleague on the count team, and 2) a rare reward that I got after birding on the Newport Pier.)

To those unfamiliar with them, Christmas Bird Counts (CBCs) are all-day bird censuses that take place within 15-mile diameter circles. Hundreds occur each winter. Each count happens on a single day between December 15 and January 4th. The location of each 15-mile circle is fixed; that is, observers count the number of every species of bird they see or hear within exactly the same count circle each year. And observers keep close track of how many people are out watching birds, over what distance they travel, and for how long, in order to have a record of how much effort was spent on the count. 

Why go out in cold, wet weather to count birds — sacrificing time that could otherwise be spent gift shopping, visiting with family, or arranging seasonal greenery in our homes? Because CBCs have become an important tool to track bird populations. If you count birds meticulously in the same area, in the same way, and for many years running, then any differences that you detect in counts between years are likely to reflect real population differences. Christmas Bird Counts have been used to document increases and decreases in the numbers of different species of birds over time and also expansions or contractions in the species’ geographic ranges. In short, CBCs produce useful scientific information; they are not just an excuse to dodge awkward political conversations with your brother-in-law over the holidays.

Of course, birdwatchers are insatiable. CBCs are just a slightly more glamorous and rigorous version of what birders do on their own throughout the year. That is, hundreds of thousands of birdwatchers in North America cover every nook and cranny of the continent, keeping track of the date, time, and number of each bird species they identify from January 1st to December 31st.

In recent years, Cornell Laboratory of Ornithology has sought to collect the information gathered by birders on their outings. No longer do most birders scribble down what they have seen in notebooks that get old and musty in a closet somewhere; they submit them to eBird, CLO’s online database. The eBird folks make the data that birders submit on their phone available to all others online and also analyze the data to infer changes in the abundance and distribution of birds. eBird has quickly become much beloved by birders as a way to keep track of and share their bird sightings. Because of eBird, we birders are no longer outright lying when we stride pompously towards the door, grasp the handle, and announce, “I am going out to do science!”

What does all of this have to do with loons? Loons appear on birder’s eBird checklists just as other birds do, of course. Because they are confined to territories, it is awkward to track loon breeding populations via eBird checklists. (Furthermore, the Breeding Bird Survey already does that.) But since birders from across the continent submit their birding results to eBird throughout the year, we can get a sense of loon population trends during winter from eBird data.

I was, of course, very excited to see the population patterns that eBird shows for loons. First, though, I wanted to see what trends showed up in eBird data from other species that popped into my head. The picture is mixed among the several land birds that I happened to check. Downy Woodpeckers, it turns out, have been increasing substantially in the past decade throughout North America. So have Red-bellied and Pileated Woodpeckers. Northern Flickers, on the other hand, have been declining across the continent since 2012. Among thrushes, Hermit Thrushes are down throughout the range; Swainson’s Thrush populations are down in the east and across the Prairie Provinces but increasing along the Pacific coast from Alaska southward to Washington state.

Looking at population trends among aquatic birds that share northern lakes with loons reveals a mostly bleak picture. Double-crested cormorants are declining almost everywhere within their range (with a few exceptions). Hooded Mergansers show declines in wintering populations along the Atlantic coast and southeastern U.S. — except along the Mississippi River, where they have increased in number. Ring-necked ducks, which we see on shallow lakes in Wisconsin and Minnesota, are down in about 85% of all winter count areas covered by eBird data, but up in the remaining 15%. Canada Geese, on the other hand, are increasing almost everywhere in the northern half of the continent (including most of Wisconsin and Minnesota), but are sharply down in northern Ontario and Manitoba.

Having convinced myself that eBird is picking up both upward and downward shifts in bird populations and also exhibiting the patterns we have seen ourselves in familiar species like Canada Geese, I turned to winter trends in common loons from 2011 to 2021. As the figure shows, almost all coastal regions from the Atlantic to the Gulf of Mexico show a decline of between 20 and 30% for this period.* There are a few exceptions — chiefly inland reservoirs, in which perhaps 2 to 3% of all loons winter — most of which show increased numbers of loons seen in winter. (The tiny widely scattered blue dots indicating these increases represent very small populations and are hard to see in the figure.)

Trends in wintering populations of common loons from 2011 to 2021. From eBird online.

If you are seeing red after studying this map, join the club. It is not a pretty picture. Winter ranges do not map onto breeding regions cleanly, so it is a bit difficult to infer population trends in breeding areas directly with this figure. However, the fact that wintering loon populations are declining everywhere in North America — even along the Pacific coast, not shown here — suggest that common loon populations have fallen broadly.**

What about Wisconsin and Minnesota? If you have followed my blog for awhile, you probably recall that loons from both states winter primarily along the entire Gulf Coast of Florida and that the remaining 20% winter in the Atlantic from Carolinas southwards. So the entire wintering range of Upper Midwest breeders is covered with red dots indicating 10 to 40% declines over the past decade. While it is important to remember that loons from other breeding populations — notably the massive Ontario and Quebec populations — winter in these coastal regions also, this across-the-board pattern is disturbing. It is, of course, consistent with what we have documented in Wisconsin and what others have documented in Minnesota.

How do we respond to this new piece of bad news about the common loon population as a whole and in the Upper Midwest? Do we fold up our tents…throw up our hands…throw in the towel? No, indeed. We get busy. Multiple problems that loons are facing and that impact the population negatively are fixable and must be fixed. So we get back to work.

WATER CLARITY GOAL

As stated on our Current Goals page, we are currently probing the loss of water clarity that is harming loon chicks to learn precisely what is making lakes less clear by testing three main hypotheses:

  • water clarity falls after rainfall because of dissolved organic matter that washes into lakes.
  • clarity declines as a result of suspended sediments carried into lakes by rainfall.
  • the decline in clarity comes because of fertilizer, waste and other human-related substances from lakeside lawns, which spawn algal blooms.

By pinpointing what is causing the loss of water clarity, we can call attention to the problem and urge state and local agencies to take action to curb it.

WINTER OCEAN CONDITIONS GOAL

We will also continue to investigate negative impacts of Florida ocean conditions on Upper Midwest loons through statistical analysis using a large long-term dataset from Tampa Bay. If deteriorating ocean conditions during winter are driving our loon population downwards, we would like to learn that now, leaving ourselves time to identify the problem precisely and — through publicizing our findings and working with state and local water quality agencies — attempt to turn things around.   

CAN YOU HELP US?

We rely solely upon private funding to support our vital fieldwork in Minnesota and Wisconsin. Our teams — wildlife students and myself — collect data throughout the summer to address our goals. Funds never go for my salary; I am paid by Chapman. Rather, funding that we receive from you supports: 1) small monthly stipends for our student workers, 2) lodging for students and me, 3) travel costs to, from and within our study areas in Minnesota and Wisconsin, and 4) supply and equipment costs (canoes, binoculars, banding supplies, and other miscellaneous items).

Thanks for any support you can give us as we work to protect Upper Midwest loons.

DONATE TO THE LOON PROJECT

* You may look at the trends reported by eBird yourself by: 1) going to their site; 2) scrolling down and clicking on “eBird Status and Trends”, 3) entering a species name, 4) grabbing and spinning the world around to see North America, 5) clicking “Trends”, and 6) zooming in and panning, as needed, to see the region you wish to see.

** This figure suggests that loon populations are falling across the breeding range. Yet we know that there are pockets, like Vermont and perhaps other portions on New England, where loon breeding populations are either stable or up in the past decade. Therefore the falling loon numbers shown for the Northeastern Seaboard must mean that other breeding populations — perhaps the very large ones in Quebec or the Maritime provinces — are responsible for the decline.

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

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

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

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

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

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

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

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

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

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

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

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

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It was just a bag in the water. But it was a large white plastic bag, one flap of which protruded above the surface of Little Pine Lake in our Minnesota Study Area. As Evrett, Isaac, and I paddled across the southern end of Little Pine to begin our observations of the Dream Island loon pair, the bag caught our eye and sullied the otherwise idyllic Northwoods scene. Looking to leave the lake a bit cleaner than when we had arrived, we fished the bag out of the water.

The writing on the bag told the story.

I have a confession to make. I come from a family of non-gardeners. When we see a beautiful tree or flower, we savor it. But the notion that some act of ours might alter the health or appearance of a plant is altogether foreign. A product of suburbs of large cities, I have grown accustomed to gazing at the verdant, manicured lawns and gardens of neighbors — then turning to look ruefully at my own. Yet jealousy of my neighbors’ lawns is not enough to induce me to follow their lead.

Of course, the suburbs are one thing. Lakeshores are quite another. The bag that Evrett fished out of Little Pine suggested that a resident on Little Pine was placing fertilizer on their lawn. While the decision of how to treat one’s lakeshore is up to each individual, it has consequences for all of us. Inevitably some of the high-nitrogen and -phosphorous fertilizer that produces a lush green lawn by the lake washes into the lake when it rains. Lake phytoplankton — free-floating, microscopic algae that inhabit all lakes — are starved for nitrogen and phosphorous just like grasses and trees on land. So adding fertilizer to lakes causes higher-than-normal growth of phytoplankton, which reduces water clarity and can have a variety of more serious impacts on lake-dwelling animals and plants.

It is too early to tell whether lawn fertilizer is at the root of the water clarity loss in the Upper Midwest during the past quarter century. We do know that heavy rainfall causes low water clarity. And we know that low water clarity hinders loon parents’ feeding efforts and produces emaciated chicks. But while we investigate the specific cause of water clarity decline, wouldn’t it be prudent for lake residents to stop using fertilizer on lakeside lawns, in case loon chicks are unintended victims?

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By the way, Wisconsin Public Radio did a short segment on our study and on the decline in water clarity we have reported recently. If you wish to hear how I sound after a day of field work and a bit too much coffee, you can find it at this link.

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When humans search for answers to complex problems, we often spend a good deal of time casting about in the dark. And our quests for answers commonly conclude with limited success or total failure. At least that is how it goes for me.

I suppose my quests are nerdier than average. In my research, I try to answer questions like: “Why do young loons seek to settle on lakes that resemble their natal one?” or “Why do female loons not yodel like males?” Still, the vexing puzzles I face in my work are not wholly different from the gnarly ones I confront in everyday life. “Why does the cupboard door under the sink never close properly?” “Why do plants keep dying in the southeastern corner of our yard?” Regardless of their origin, life is full of riddles that are challenging to address — and rewarding to solve.

This fall, I have been investigating factors that influence masses of adult loons and chicks. Most predictors of adult male mass* are easy to understand or, at least, lead to highly plausible and testable hypotheses. Males show a long-term decline in average body mass that began thirty years ago and continues today. This result suggests that human encroachment of some kind has made it harder for loons to maintain optimal body condition — and is getting worse. Recently we also found that adult males have lower mass on territories with a high density of docks. Again, we can understand how more docks — and more angling — might hinder adult male foraging and lead to lower mass.

Likewise, most predictors of chick mass are easy to explain. Short-term water clarity affects chick mass strongly. We have known for over a year that lower aquatic visibility hinders loon foraging. And I was not surprised to learn that a chick’s mass is correlated with that of its mother. It stands to reason that body size would be heritable in loons, as it is in other species. Finally, like their parents, chicks show a long-term downturn in mass over three decades that hints at environmental degradation. These three statistical relationships make perfect sense.

In fact, a brain twister did not emerge from this recent analysis until I looked at the relationship of dock density and chick mass. You see, chick mass is positively correlated with dock density. That’s right: the more docks there are on a lake’s shoreline, the fatter the local loon chicks become! The result is astonishing for two reasons. First, it runs counter to logic; second it is opposite to the male pattern. How could more docks — and thus more boaters and anglers — help chicks gain mass, when the same factor is harming their male parents?

I checked and double-checked the statistics. I scanned the data for abnormalities. Many days of fruitless pondering passed. At last I hit upon an idea that was hiding in plain sight: maybe the anomalous pattern had to do with food. Now, the data on fish abundance in our study lakes is of poor resolution and contains many holes. In fact, there are not enough data from any of our 205 Wisconsin study lakes to compare fish abundance with chick mass directly. Still, scientists have collected reams of data on abundance and size of fishes statewide. So we know a good deal about broad patterns.

A recent long-term analysis of fisheries shows that small fishes favored by loons — bluegill, yellow perch, crappies — have been declining in average size across the state for 70 years. The decline in panfish sizes — a consequence of overfishing, according to fisheries biologists — provides a plausible explanation for the long-term loss of mass in adults and chicks. Loons, it seems, must work harder each year to capture enough panfish to sustain themselves. This broad decrease in panfish size in Wisconsin lakes, therefore, might explain why masses of chicks and their male parents have declined in recent decades.

But how do we explain why loon chicks gain mass in busy lakes while males lose mass? Remember, when young, chicks can only swallow very small fish (as Linda Grenzer’s photo shows). Even at five weeks, chicks consume fish smaller than those that adults do. This appears to be the key point. Young chicks ingest small fishes — the very size-class of fishes that thrives when larger fishes are removed from the lake by anglers.**

So I have solved a puzzle related to loon feeding ecology. Well, more accurately, I have generated a highly plausible hypothesis that is consistent with the data but will require further testing. For the moment, I am quite satisfied with this outcome. Because I am a scientist, and that is how we roll.

*We have a large sample of males than females, so our analysis of male mass is more robust.

**While we might celebrate that young loon chicks appear to benefit from human overfishing, this news is not cheering. The first five weeks of a chick’s life, after all, is only one critical phase that it must pass through. This year’s hatchlings are 13 to 18 weeks old now. Their diet is now identical to their parents’. Like their parents, 2023 juveniles are finding fewer large bluegills, perch, and crappies. So they too must spend more time foraging than they did 30 years ago. Could the dearth of large panfish on the breeding grounds help us understand why loon survival from the late juvenile stage to adulthood has declined precipitously in the Upper Midwest?

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Many of my colleagues fear ChatGPT. They fear that students will use this new online tool based on artificial intelligence to generate papers and answer questions on homework assignments that students are meant to tackle themselves. Their fear is legitimate. Why? Because if you read ChatGPT’s answers to a range of questions, you notice something rather quickly. ChatGPT generally produces plausible, thoughtful, coherent responses. Furthermore, ChatGPT writes well — at least compared to what I see from most of my undergraduate students. In short, ChatGPT creates headaches for instructors. It is forcing us to reconsider how we evaluate our students.

On the other hand, I was excited to learn what this new AI tool would produce when asked about loon biology. I asked ChatGPT: “Do loons mate for life?”. It responded:

While common loons often return to the same breeding territories and may reunite with the same mate from the previous year, these pair bonds are not necessarily permanent. After the breeding season, loons typically migrate to coastal or open water areas for the winter, and their social behavior can be more flexible during this time. When they return to their breeding territories in the following spring, they may or may not reunite with the same mate.

Now, this is not a terrible answer. ChatGPT is correct when it suggests that loons do not mate for life. But its mention of migration is off-topic. Its point regarding “social behavior” during winter is irrelevant. Its statement that loons “may or may not reunite with the same mate [in the spring]” is grossly misleading. And ChatGPT has entirely failed to mention the chief reason why loons do not mate for life: territorial eviction.

ChatGPT’s responses to loon-related questions are similar to its answers on other topics. The program searches the web for information from which to build its responses. But because these responses draw information from countless online sources, they include the good, the bad, and the ugly. In short, ChatGPT gives you a blur of “conventional wisdom” about any topic, not rigorous and precise scientific truth. Its answers are, for the most part, uncontroversial, vague, and riddled with caveats.

I turned my attention to loon conservation. When I asked, “Are any common loon populations in trouble?”, ChatGPT came back with:

As of my last knowledge update in September 2021, the status of loon populations, particularly the Common Loon (Gavia immer) in North America, varied by region and was a subject of concern in some areas. Common Loons were classified as a species of “Least Concern” by the International Union for Conservation of Nature (IUCN) due to their relatively stable population at the global level.

However, it’s important to note that local and regional populations can face significant challenges, including habitat loss, water pollution, lead poisoning from ingesting fishing tackle, disturbance from boating and recreational activities, and climate change impacts on their breeding and wintering grounds. These factors could affect specific loon populations and lead to localized declines.

ChatGPT is spot on in some respects. Loons are in no trouble globally. And the status of populations varies from one region to another. But the program uncritically lists many anthropogenic factors that might harm loon populations and provides no specific information. One might infer from ChatGPT’s statement that we must solve all of the problems listed in order to preserve loons. Or perhaps loon populations face many obstacles but none is severe enough to cause serious harm. In truth, we do not know which, if any, of the listed factors might endanger loons. Furthermore, ChatGPT has failed to mention two factors — exploding black fly populations and decreased water clarity — known to harm loon populations in the Upper Midwest. If this had been a class assignment, ChatGPT would have earned a “C-“.

ChatGPT’s take on factors threatening loons sounds eerily familiar to what we loon conservationists often say. (I include myself in this group.) That is, we often settle for a ChatGPT-caliber pronouncement about loon conservation. We say or imply that if we: 1) enact a lead ban, 2) reduce human settlement on northern lakes, 3) eliminate water pollution, 4) keep boaters away from adults and chicks, and 5) halt climate change, then we can save loons. These goals, of course, range from difficult to impossible to achieve.

A ChatGPT-like approach will not save loons. We simply cannot eliminate all threats. In fact, many factors that loon conservationists perceive as threats pose little or no hazard. The best example is human recreation. While lead sinkers are a danger to loon populations because of the many breeding adults they kill each year, loons are well-equipped to handle boaters. Loons tremolo, wail, or yodel when boats are too close to them or their chicks. They penguin dance, charge, and dive noisily at boats that creep close to their nests. Humans usually interpret these warnings correctly and back away in short order. Moreover, the low rates of mortality and nest abandonment attributable to boating activity indicate that loons tolerate human interactions well.**

How do we distinguish between relatively benign environmental factors, like boating, and those that truly endanger loon populations, like black flies, lead sinkers, and water clarity? Science. Only science will save loons. If the Minnesota loon population is declining and 50% of loon deaths result from lead poisoning, the folks in Saint Paul will take notice. If Wisconsin loons fledge 40% fewer offspring nowadays than in 1995 because of lower water clarity, that will make headlines in Milwaukee. And if the fledging rate across the Upper Midwest is 30% lower owing to black fly-induced nest abandonments, that might turn apathy concerning climate change into action.***

So if you are an unprincipled student being taught by an inattentive instructor, ChatGPT might earn you a “B” on your history paper. And if you cannot get the wording right in a letter to a client or colleague, ChatGPT might provide suggestions. But we loon conservationists should resist the uncritical, shotgun approach that ChatGPT takes to addressing questions. If we are going to preserve loon populations that we treasure, we must first collect data. And then, in our communications with the public, politicians, and the media, we must highlight the specific environmental hazards that science has shown to be dangerous to loons.

* The featured photo was taken a week ago by Linda Grenzer of an adult male from Lake Winter, Wisconsin that swallowed a lead sinker. Though the sinker was surgically removed by Raptor Education Group in Antigo, the male died two days later from the lead it had already absorbed.

** I might be biased by my work in Wisconsin and Minnesota in my conclusion about loons coping with boating activity. It is conceivable that boats do cause enough nesting failure and/or chick mortality in some regions to threaten loon populations. We do not have data to show such a pattern, however. If you know of such data, please let me know.

*** I made up these three numbers. We are still collecting data on loon mortality caused by lead sinkers. Only recently have we learned about the threats of black flies and loss of water clarity. We and our partners are recording many lead-poisoned loons these days. We will publish an estimate of lead’s impact within five years. Robust estimates of the impacts of black flies and water clarity on loon populations in Wisconsin (and possibly Minnesota) should be available by sometime in 2025.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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Ensconced as I am in the endless summer of southern California, it is easy for me to forget what loons are facing. As we know from Kevin Kenow’s excellent work, about half of all adults have now left their breeding lakes in Minnesota and Wisconsin and are on their way southwards. Many of these birds are hanging out in the Great Lakes before making the long overland journey to Florida. Some adults remain faithfully with their chicks, hoping to stuff a few extra fish into them before abandoning them to their own devices.

Adults’ departure leaves only chicks on the breeding grounds. Thanks to the the work of our fall observation teams and Brian Hoover, who pulled the data together and wrote it up, we know that most juveniles leave their natal lakes in the fall but hang out nearby. They search diligently for large, food-rich lakes, especially favoring those that resemble their natal one in pH. Their strategy is clear. First, stuff your face with fish where they are abundant and similar to the ones you first learned to hunt. Next, wait until the last possible minute to build up your energy stores. Finally, bolt for Florida before the ice makes it impossible to take off.

The juveniles’ plan has a touching pragmatism to it. There is no subtlety. Birds of the year are not burdened with territorial responsibilities or pangs of parental guilt. They just wish to survive long enough to reach the wintering grounds. And, generally speaking, they do.

But a few get left behind. Thus it happened with the Lake Thompson juvenile this fall. A great strapping youngster when we caught him in late July at five weeks of age, he continued to grow and thrive in the 12 weeks since we last saw him. Ultimately, he had no more need of his parents and moved five miles west to Boom Lake in Rhinelander to fatten up for migration. There, however, he ran afoul of a reckless hunter. Linda and Kevin Grenzer caught him last night and quickly saw that his left wing was fractured. X-rays at REGI confirmed the break — caused by goose shot visible in the x-ray.

I cannot think what else to say.

Top photo by Linda Grenzer. X-ray by REGI staff.

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We all love loons. So naturally we should take any step we can to help them. Right? In that light, artificial nesting platforms (ANPs), or loon rafts, would seem to be a no-brainer. Platforms make it easier for loon pairs to produce chicks.

ANPs fit neatly within the framework of loon conservation. Accepted enthusiastically by most loon pairs, they would seem to provide a perfect, low-cost solution to increase loon populations. They are easy to construct; a person with a modicum of carpentry experience can find plans online and build a platform in a day or less. So platforms provide a simple method by which a single loon enthusiast can improve the breeding success of a pair of loons for many years. Across the loon breeding range, platforms have become a panacea for bolstering reproductive success.

But are nesting platforms all that we need them to be? Now that loon populations appear to be in trouble in Wisconsin and perhaps even in Ontario — and now that some of the causes of declines are beginning to come into focus — maybe it is time for us to step back for a moment. Maybe we should ask whether platforms address the actual problems that loon populations face. To state it technically, can platforms mitigate the specific negative factors hurting loon populations and make populations viable in the long term?

We first need to recognize that platforms address a single, very narrow problem faced by loons. Loon pairs must sit on their eggs — in an exposed location — for 28 days. If a mammalian predator wanders by during that month, the nest is lost. Platforms solve this problem beautifully. They increase the rate of hatching by about 70%. But putting chicks in the water is all platforms do. Platforms do nothing to help chicks reach fledging age. They do not feed chicks; they do not protect chicks from predators. They do not boost adult loon survival. They have no effect on the rate of boat strikes or angling casualties or lead poisonings of adults and chicks. In short, if loon populations suffer declines owing to reduced hatching success, then nesting platforms are just what the doctor ordered. If declines are caused by anything else, then platforms would appear ill-suited to the task.

What do we know at this point about the status of loon breeding populations and factors that might threaten them? Precious little, if we are talking about the entire species range. But we have begun to narrow down the list of population threats in the Upper Midwest.

At present, the four most significant hazards to loons in northern Wisconsin appear to be: 1) larger populations of Simulium annulus, a black fly that targets incubating loons and causes massive abandonments of loon nests in May and early June, 2) decreased water clarity during the chick-rearing period, which increases chick mortality, 3) increased deaths of adult loons and chicks from ingestion of lead sinkers and jigs, and 4) a die-off of young adults resulting from poor feeding conditions that they experienced during the first five weeks of life that has a delayed negative impact on adult survival.

How well does the use of nesting platforms to boost hatching success of loons map onto the quadruple threat of increased black flies, decreased water clarity, lead poisoning, and spiking mortality of young adults? With respect to black flies, platforms might mitigate the problem somewhat. Platform-nesting loons suffer abandonments just as severely as do loons nesting at natural sites, but the increased hatching success of second nests on platforms offsets the hit to hatching success caused by black fly-induced abandonments of first nests. Platforms, of course, have no impact on the decreased growth rate and increased mortality of loon chicks owing to declining water clarity and the resultant difficulty of feeding chicks. Likewise, platforms do not affect the incidence of lead poisoning. And platforms provide no relief to loons from the silver spoon effect, whereby individuals reared with limited food survive poorly as young adults.

On the whole, then, floating nest platforms do not appear to address effectively the major threats faced by loon breeding populations (to the extent that Wisconsin represents loon populations generally).

While that quick analysis might seem reasonable, I have ignored one crucial fact about loon nesting habitat and platforms. Platforms often provide loons with an opportunity to breed in lakes or parts of lakes where they otherwise could not because of the absence or poor quality of nesting habitat. In other words, platforms actually create new nesting habitat. If the new nesting habitat that platforms make available contains enough food that parents can fledge the chicks they hatch there, platforms might provide “bonus chicks” that give the loon population a boost. *

Of course, platforms are so enticing to loons that they must be deployed thoughtfully. A platform placed on a very small lake might lure a pair of loons to use it but result in starvation of the chick(s) because of food limitation. Since a pair lured into such a tragic situation might otherwise have nested and reared chicks successfully elsewhere, such misuse of nesting platforms exacts a cost on the breeding success of the population. (Loon conservationists recognize the pitfalls of using nesting platforms thoughtlessly and only deploy them where they are likely to do more good than harm.)

While loon platforms seem effective at boosting loon populations in some respects but ineffective or even harmful in other respects, what conclusion can we reach? We cannot be too confident of any conclusion at this point. But since it is becoming clear that poor foraging conditions during the chick phase is the greatest problem for loons and that limited food during the chick phase can doom a loon to a short adult life, we would do well not to pat ourselves on the back too hard for adding a platform that puts a few extra chicks in the water.

* Population ecologists will recognize a potential flaw in my reasoning. Even if platforms result in a huge increase in fledged chicks in a population, density-dependent mortality during winter or migration (e.g. owing to food shortage) might wipe out all of these extra individuals. In that case, platforms would not be an effective conservation tool. In fact, increased adult mortality from a variety of causes could produce population decline even in the event of huge “bonus” chick production via platforms.