Early spring research takes a special kind of mettle. With winter merely loosening its grasp on the North, but not letting go entirely, many boat landings remain iced in — like the one Linda found at Hilts Lake today. Meanwhile, inconvenient portions of each lake become ice-free, and returning loons hang out there. In the photo above, for example, Linda is trapped at the public landing, far from an ice-free strip of lake on the northwest side. So the birds are, for the next day or so, inaccessible. Sometimes, too, entry roads are blocked or impassable, as Linda found yesterday on O’Day Lake, where one of our oldest females (marked in 1996) breeds. We will have to come back to these lakes when conditions are more favorable for our work.

Early-season census, which involves visiting lake after lake to verify IDs of all loons found, can be a frustrating business. Not only are conditions unpleasant, loons move around. As part of their ceaseless quest to stay a step ahead of raccoons, loon pairs that lost eggs in one year will check out adjacent lakes in early spring of the next year to search for better nesting sites. Thus, one can fight one’s way to a boat landing and dodge ice slabs to reach open water, only to find that the breeding pair is off scouting a nearby but unknown lake.

The upside of observations of loons in April and May is the excitement of seeing which of our marked study animals have returned. As many of my posts have made clear, we get to know and love our loons, especially the tame ones that permit us to approach to within a few meters and identify them from their bands easily. So each year I read with great anticipation the list of returning breeders that Linda, Nelson, and other scouts have found. These birds — and this does not feel like an exaggeration — are my friends.

This year I get to help with scouting. While normally I would be bogged down with teaching until the middle of May, my sabbatical this spring allows me to join Linda in the challenging task of identifying our returning breeders. Within a week, I will be zipping around from lake to lake, hoping at each stop that both pair members will be right off the boat landing, roll-preening to show off their leg bands. A few weeks later, Elaina, who worked with us last year, will join us as well. We are short-handed in 2019 and will not have a banner year for data collection, but the three of us will do what we can to hold down the fort.

 

Several events were happening at once last June. I was about to turn 60. The entire college of science at Chapman was moving to a new building. We had just brought our loon research goals to a conclusion, which left me uncertain what questions to tackle in the future. Most important, the money was running out. These events conspired and left me thinking: should I keep studying loons? Or is it time to step back from field research and devote my energy to service to the University?

This question loomed over me for many months. When anyone asked, I was pushing ahead with plans to look at causes of aging in loons through our study of telomeres, but doubt nagged at me each day. Why continue? Have I answered all of the important questions? Should I just rest my back and write my book?

Strangely, I pulled out of this funk not through some unexpected statistical breakthrough or spellbinding discovery but by writing a grant proposal.

To me, grant proposals are a necessary evil. I do not enjoy marketing my ideas to colleagues in my field, who will weigh in with a thumbs up or down – perhaps for the wrong reasons. Selling ideas in an effort to secure funds seems shameless and mercenary. I became an academic in the first place partly to avoid such work. Yet to many scientists, grants are the bread and butter. Without funds to purchase equipment and supplies and hire personnel, most of us are quite limited in what we can study. So we write grant proposals.

Although I had pieced together the rudiments of an outline during this past summer, it was not until November that I started to turn that outline into the introduction and body of a proposal. Even then, I moved at an almost comically glacial pace. Each finished sentence, it seemed, was a great victory and warranted taking time off to recharge. I would find a clever opening phrase and birdwatch for two hours; locate a useful journal article and birdwatch for three. I was going nowhere.

Oddly, I gained momentum. As I added a reference here, ran a new statistical analysis there, a robust, compelling set of hypotheses began to emerge. In the process of constructing a document to convince other ecologists that I had ideas worthy of testing, I convinced myself that I had such ideas. What had begun as a hollow, pro forma exercise culminated in a thoughtful, executable plan for ten years of future loon research directed at the question of why loons settle and breed on small lakes that produce few offspring.

So I am back on track. Far from drifting numbly towards a new research season, I am energized and anxious to hit the lakes again. The sense of dread at facing a year of field work short‑staffed has lifted. Now I relish the challenge of keeping tabs on all of our study animals this summer with fewer field workers – as long as my back holds out.

 

 

We have known it for some time. Young loons looking for territories observe chicks on a lake and return the following year, hoping to evict one of the resident pair members and take over the breeding position. The effect is dramatic; the intrusion rate increases by 70% following a year with chicks.

From the viewpoint of a young floater (a young bird that has not yet settled), chicks are a boon. The mere sight of young encapsulates all of the information necessary to size up a potential breeding location. Instead of having to learn about breeding success by trial and error, the floater need only seize an existing territory that has proven to be a chick producer. (Of course, seizing a territory has costs.)

From the breeders’ standpoint, raising a chick is like painting a great big target on their backs. Those little brown fuzzballs look cute in the moment, but their presence portends many battles with floaters the following year. No wonder parents take steps to hide their chicks, when they can.

A week ago, during the writing of my proposal to NSF, I made another finding related to chick production and its impact on a territorial pair. In this case, I was examining our data related to aggression between breeders and floaters, which can take the form of grappling battles between two loons, lunges by one loon at the other, chases across the water, or severe feather damage to the head of the breeding bird — evidence of a recent violent encounter. In a few cases, I could infer aggression because a pair member was injured on its territory after having been healthy a few days beforehand. When I threw all of observed aggression or evidence of past aggression together and asked whether it was related to chick production, I found that more aggression occurs per visitor both in a year in which chicks are present and also in years following chick production.

Now you might wonder whether I have moved the needle here. We already knew that chick production causes a spike in territorial intrusions the following year; what extra information do we get from knowing that aggression also spikes? The answer relates to costs. Just visiting a chick-producing territory more frequently expresses interest in the territory. The fact that floaters elicit a greater rate of aggression per visitor tells us that floaters are willing to incur costs (i.e. the cost of injury) while visiting such territories. In short, floaters flock to successful loon territories — and they mean business when they do so.

 

It is only a glimmer — the kind of glimmer one often gets when eyeballing new data. But the implications of this small discovery are enticing.

You see, I have been looking at our data on tameness, Since 2014, our team (mainly Kristin, Seth, Mina, and Nelson) has measured tameness of loons by creeping up to birds resting on the surface. We do this by first measuring our distance to the loon with a rangefinder and then paddling slowly in its direction, taking distance readings every few strokes. The final distance reading — just before the loon dives to avoid us — is our measure of tameness. Determined in this way, tameness varies from well above 50 meters to less than 2 meters. (In fact, some of our marked birds, like the male in Linda Grenzer’s photo above, find our approach so unremarkable that they simply veer slowly out of our path, instead of diving.)

We can examine the origins of tameness in far greater depth than most other studies, because we have tameness readings on many sets of close relatives in the study area. In fact, owing to the duration of our study, the limited natal dispersal of many individuals (especially males), and our efforts to find adults that we banded as chicks, we now have tameness measured for 60 sets of relatives. These include Linda’s male (“Clune”) and his son, who breeds on tiny Virgin Lake; the notoriously skittish male on Oneida-East and his full brother on Hughitt; and the Bear female and her full brothers on Cunard and Gilmore (all three banded 13-15 years ago on North Nokomis Lake).

As the figure below shows, we have noted a strongly and statistically significant relationship in tameness between parents and offspring. This pattern implies that either: 1) offspring inherit their tameness from parents, or 2) parents teach their offspring to be tame or skittish during the chick-rearing phase (or both). Either way, similarity in tameness between adults and their young means that despite being measured on different lakes, many years apart, and at very different ages, tameness is stable within individuals and is largely fixed early in life. A loon’s degree of tameness is, in effect, part of its personality.

Screen Shot 2019-02-17 at 10.00.46 AM

Parent/offspring similarity in tameness is more than a hollow novelty. Since tame parents produce tame young (either via genetics or rearing environment), those young should respond to the habitat in much the same way as their parents. I am in the process of writing a proposal to the National Science Foundation to study, among other topics, the possible impact of loon tameness on habitat selection. Specifically, I wish to test the hypothesis that tame loons might be suited to lakes with lots of human recreational activity (generally large lakes) and skittish loons to lakes with limited human activity (generally small ones). If this logical hypothesis holds up, then pity skittish individuals. Since human activity is increasing, and even many small lakes now see frequent human usage, skittish loons appear to have a small — and shrinking — set of lakes on which they can breed. Moreover, the reduced chick production of small lakes might also doom skittish loons to poor breeding success, so that fewer skittish individuals are produced each year.

The long-term consequences of parents passing skittishness to their young and fewer offspring produced by skittish loons are easy to guess. Tame loons will produce a large proportion of all offspring in the northern Wisconsin population, and tameness should increase in frequency in coming decades to the point where skittish loons are hard to find at all. This vast behavioral shift might go unnoticed by most observers, since there will still be loons on the lakes. But to an ecologist, it is exciting to think that we might be on the brink of learning the precise mechanism by which a population of an important animal can become tame.

 

 

I have touched upon this theme before. A peril of longitudinal investigation is that one decides, after a period of time, that one understands the system. So it has been with the Loon Project.

For many years I have thought I had a good handle on territorial behavior. Indeed many aspects of the loon territorial system have become clear during the course of my work and are not in doubt. Both sexes usually fight to claim their territories and face the constant threat of eviction. Males, which establish strong ties to a territory through controlling nest placement and learning where the best nest sites are, fight harder than females, and sometimes die during territorial battles. Early senescence among males sets the stage for them to become very territorial and aggressive as they reach their declining years (their mid-teens in many cases), which seems a means to help them eke out another year or two on a familiar territory.

But I might have been off in my understanding of the role of lake size and body size in territorial behavior. I have always thought of breeding territories on large lakes as much sought-after, because large lakes have ample food for rearing chicks. (Small lakes, you might recall, run low on food for chicks, resulting in lower fledging success.) If large lakes produce more young, I reasoned, large-lake territories must be highly desirable. Competition must be fierce, then, for these territories. A recent analysis of territorial tenure — how long a male or female can hold onto their territory before getting evicted from it — has forced me to rethink the effect of lake size on territorial competition. The figure below is a plot of territorial tenure versus body mass for males on lakes smaller than 20 hectares (50 acres) in size (like Langley, whose current pair is pictured). As you can see, small males — especially those below 4600 grams — have very short stays on small lakes, in most cases, while large males — notably those heavier than 5000 grams — often enjoy very long territorial tenure. This pattern suggests that, contrary to my expectation, territorial competition is fiercer on small lakes than large.

impact of lk size, male body size, on terr tenure

Let’s look at the same pattern on medium-sized lakes (20 to 80 hectares; or 50 to about 200 acres). You can see that the overall pattern is still evident, although it is weaker here, because a number of very large males (5400 to 5800 grams) have anomalously short tenure.

i2 mpact of lk size, male body size, on terr tenure

Finally, let’s inspect the data only for males on lakes larger than 80 hectares (200 acres). In contrast to my earlier hypothesis, large males are not holding their territories any longer on large lakes than are small males, as you can see from the plot below. Males of all sizes may enjoy long tenure on large lakes.

3impact of lk size, male body size, on terr tenure

How on Earth do small males hold their territories much longer on large lakes — which  seem much in demand, get more intrusions, and appear difficult to defend — than on small lakes, which get fewer intrusions and should be more easily held? I don’t know exactly how males hide in plain sight on large lakes, but it might have to do with the difficulty that territorial intruders have in simply finding a nesting pair and identifying nesting habitat on large lakes. Consider the Lake Tomahawk-Little Carr pair. This pair nests in a marsh at a well-hidden location. When one bird is incubating, its mate is usually far off in the wide open portion of Lake Tomahawk, which is many kilometers long and has an area of 1400 hectares (about 3500 acres). A male intruder might well find and socialize with the off-nest pair member on on the big water, but it would have no way of knowing that the mate of this loner was on a nest hidden far away in a marsh. Similarly, when the eggs hatch, the pair quickly leads the chicks to the main bay of the lake, far from the critical nesting area. Pairs with chicks provide an enticing cue to young males seeking territories, because the presence of chicks tells of the availability of nesting habitat. But a male intruder that encounters the Tomahawk-Little Carr pair and their chicks on the main bay of the lake would face the needle in the haystack problem in locating the precious nesting area that yielded the chicks. A dangerous battle might win the territory, but the knowledge of how to use the territory (that is, where to place the nest) would vanish with the old male’s departure. Hence, large lakes appear to be less valuable to males.

A male intruder bent on taking a territory likely to yield chicks in the future would be better-served by evicting a chick-rearing male on a small lake. Such an intruder would have a much smaller set of nesting areas to inspect and would likely find and use the nesting area that produced the chicks. Thus, we might expect stronger competition among males for small, easy-to-learn territories — a pattern that dovetails with the longer tenure that large, competitive males enjoy on small lakes, compared with small, easily-evicted males.

What about females, you might ask? Do large females on small lakes, like large males, have an advantage in holding their territories when compared with large females on large lakes? If my hypothesis is correct, and the value of a territory depends upon knowledge of safe nesting areas, then large female size should not be especially beneficial on small lakes. Indeed, any impact of female body mass on territorial tenure should be equal across all lake sizes. Why? Because females do not control nest placement in this species. An intruding female that evicts a breeding female with chicks and pairs with the breeding male would have access to that male’s knowledge of nesting sites on a lake of any size. As predicted, large size is no more beneficial to small-lake females than large-lake females. (Indeed, size has an overall weaker effect on competitive ability in females.)

So my post hoc hypothesis for the fierce territorial competition on small lakes holds for the time being. The explanation I have given is not the only one consistent with these data, by the way. In fact, the entire complex pattern described above might be explained by a completely different scenario. Large males might hold small territories longer simply because they are in better body condition. This is highly plausible, because mass is a good predictor of health and condition. Thus, only large males might be able to hold onto small lakes for a long time, because they are in good enough condition to survive in a habitat with limited food. Small males, by this logic, are already in sub-prime condition, so they are destined to have short territorial stays on lakes with limited food. In contrast, medium-sized and large lakes do not show the pattern, because food is not limited on them.

As you see, we have a long way to go to figure out exactly what the above graphs are showing us. Distinguishing between the “small-lakes-are-highly-competitive” and the “holding-small-territories-requires-good-body-condition” hypotheses will take some years. The difficulty of using what seem like beautiful, clear data to reach a firm conclusion provides a nice window on what it is to be a scientist.

 

 

Behavioral ecologists are human. Although we try hard to view biological events critically – to look for confounded factors, biased samples, untested assumptions – we miss a lot. So it is when we look at the nesting behavior of birds.

Ecologists around the world have made a simple, elegant discovery about how birds respond to nest failure. Once they have settled on a breeding territory and reared young successfully once, breeding birds get conservative. They reuse the same nesting site again and again. On the other hand, if they try to nest in one location and the nest fails, they shift to a new location. We call this simple strategy the “win-stay, lose switch” rule.

Let’s think a bit more about the win-stay, lose-switch (”WSLS”) nesting rule. What is it about a nest’s location that links it so critically to success or failure? The main answer is predation. Most predators are long-lived mammals (raccoons, squirrels, foxes), reptiles (mainly snakes), or birds (crows, jays, hawks, or gulls) that travel within fixed small ranges looking for food throughout their lives. If a bird’s first nesting attempt is not found and gobbled up by a vertebrate predator, a second one at the same site will likely escape predation as well. On the other hand, a raccoon, blue jay, or rat snake that found and ate your eggs at one site in mid-May will likely do so again in June, if you reuse the nest site. By moving away from the site of a failed nest, you might find a new site that does not fall within the predator’s home range – or is better hidden or otherwise inaccessible to the animal – and the prospect of successful breeding is renewed. That is the simple beauty of the WSLS rule.

While predation is the most obvious and important reason for using the WSLS rule, there are other reasons why moving a nest might be beneficial following failure. A species like the cliff swallow, whose nests become infested with swallow bugs – blood-sucking insects that attack and kill nestlings – should (and does) respond to infestations by moving the nest. The key point: vertebrate predators and tenacious parasites are persistent and location-specific nesting threats. To place a new nest at the same spot shortly after losing a first one to such a threat is to court disaster.

The WSLS rule has been confirmed as a logical and successful nesting strategy by ecologists around the world. Numerous theoretical papers have been written about it (including one by me). The rule is so widespread that scientists often think of it as “the way” that birds respond to nest failure. But closer inspection of nest failures shows that we have oversimplified the picture.

Nest failure can also occur owing to threats that are fleeting and non-location-specific. Fleeting, non‑location-based threats are those that occur at a brief moment in time, are not likely to recur soon, and are no more likely at one location than another. Examples are “freak” weather events, like early spring snowstorms or heat waves. Fleeting threats of this kind usually end quickly – so quickly that they abate before the nesting pair can even lay a new clutch of eggs. Fleeting threats make very different demands on nesting birds than do persistent threats and should be countered with a different strategy. Why? Think of a pair of loons whose nest has been flooded by a 6-inch rainstorm. If the pair were to use the WSLS rule to respond to this fleeting threat, they might move their nest away from a traditional nesting location (say, a favorite island) that they had used to produce many fledglings in years past and choose a new, untested nesting location. In so doing, the pair would discard years of accumulated knowledge about their territory and  dim their breeding prospects.

What is the proper response to a fleeting threat of nest failure? Nothing! That is, the logical and adaptive response (i.e. that which maximizes the chance of breeding success) is to ignore fleeting causes of nest failure and consider the next nesting attempt a “do over”. Do birds have the capacity to respond differently to different causes of nesting failures? It is too soon for a general statement, but loons can do so. If a predator gets their eggs, loons use the WSLS rule (i.e. they move the nest). If a fleeting threat causes them to abandon their eggs, loons ignore that nesting attempt, often placing a new set of eggs right back in the same nest they started and abandoned a week or so before.

Followers of the blog will know that loons face a fleeting (but very severe) threat to nesting that most other birds do not: black flies. Perhaps their vulnerability to black flies — which typically only cause nest failure for a week or so in late May —  has caused loons to evolve a more sophisticated response to nesting setbacks than other birds. I have begun combing through the literature on avian renesting behavior in order to determine if, indeed, the nuanced renesting behavior of loons is unique. Since I have just started, we can bask for the moment in the possibility that loons are a cut above the rest.

Loons are always with me. With its fires, mudslides, and Mediterranean climate, southern California could hardly be more different from northern Wisconsin, but the loons winter here. I see them at Newport Pier, a bustling wharf that juts out into the Pacific and draws scads of Vietnamese anglers…..and me. The chattering fishermen are after pacific mackerel, which feed beneath the wharf in great whirling clouds. I am looking for pelagic birds that might fly by, like red-footed boobies, pomarine jaegers, and common murres. But I always see loons too. In fact, common, pacific, and red-throated loons all occur along the coast of southern California in good numbers.

My first sighting this morning was auspicious; I spotted a fast-flying parasitic jaeger as I reached the end of the pier. Small pods of common dolphins surfaced at intervals as they too pursued mackerel, exciting the gulls and pelicans near them. Great rafts of western and Clark’s grebes stretched out north and south of the pier. Experience told me that these circumstances were likely to produce a rare bird sighting.

As I completed my initial scan of the water adjacent to the pier, I saw a common loon with a buoy near it — at least, the odd dayglow-pink item near the loon registered as a buoy on my first glance at it through my spotting scope. (A photo taken with my phone through the scope appears above.) As I studied the loon and pink item further, I realized it was a bobber connected to one of the legs, because it followed along a foot behind and bobbed up and down rhythmically as the bird swam slowly along the surface. I groaned. Even in winter, apparently, loons face fishing entanglements.

My relaxing birding trip at an end, I watched the loon for an hour to learn how it was coping with the fishing gear. Fortunately, it swam southward during this period, which, bit by bit,  brought it closer to the pier. Despite the cheerful fishermen whose casts and puttering about blocked my view at intervals, the loon was simple to track. Early on, another common loon approached and preened within a few meters. The entangled loon remained alert but showed no other obvious response. Similarly, it ignored a smaller pacific loon that came near while diving. A second common loon came over and showed a hint of social behavior, such as we see in the breeding season. For a third time, the loon with the bobber made no response. The bird did not even react noticeably when a juvenile western gull flew over, settled beside it, and began to pick at the bobber. At all times, the entangled loon sat high in the water; it never dove, preened, or even gave a wing flap.

The lack of social interaction, disinclination to dive or exhibit other normal loon behaviors, and posture of the loon in the water speak volumes about its condition. These signs indicate that it has probably been dragging the unwanted bobber for some days and is severely impacted. Fortunately, bald eagles, the loons’ nemesis during summer, are rare in southern California, so the loon is not likely to succumb to predation. But its inability to dive means it has already begun to lose weight and become weak. It will surely starve if the bobber is not detached soon. I will visit the pier tomorrow to see if I can relocate the bird. If so, and if its status appears unchanged, I will see if I can put together a capture team. With great luck, we might free the doomed bird.

 

In the dream, I am swimming in a tiny lake – a lake so small that two residents on opposite ends of it could converse without raised voices. The lake is completely encircled by cottages. Docks overhang almost every inch of shoreline, looming menacingly over the water and rendering the lake smaller still. The lake, in fact, looks more like a pond hastily dredged by developers for a suburban apartment complex than a pristine aquatic habitat where loons might live. But in the dream a pair of loons swims about the lake with me, investigating future nest sites after having lost their first nest of the year to a predator.

I awoke yesterday with this dystopian scene vividly in mind. The dream reflects, I suppose, my growing unease over the future of loons along the southern fringe of the species’ breeding range. My concern is fueled by an ongoing analysis of the decline in chick survival since 1993.

That analysis has progressed since I first mentioned it. The investigation started as just a hunch — an uneasy feeling that singleton broods were becoming more common. Now, having looked at the data formally in a controlled analysis, I have brought the decrease in brood size more sharply into focus and verified that it is real. There has been a systematic, highly non-random decline in brood size over the past quarter century in Oneida County.

My worst fear took shape in the dream. I fear that growing recreational pressure, shoreline development, and perhaps environmental degradation have conspired to rob breeding pairs of a chick here, a chick there — to the point where the population might be affected. My recent analysis provided a hint about the cause: the decline is far greater on large lakes than small ones. Large lakes, of course, are those most affected by increased human recreation.

It is early still. I have much investigation yet to do, especially testing specific measures of human activity (like fishing or boating licenses issued in Oneida County) to see if they are tightly correlated with chick losses. But for a worrywart – and a vivid dreamer – these are unsettling times.

As my family and friends will tell you, I am judgmental. When an event happens that could be attributed to mindless error, I am inclined to view it, instead, as deliberate selfishness or irresponsibility. I derive my hypercritical worldview in part from my profession. As a behavioral ecologist, I presume that much of the behavior we see in animals (including humans) has evolved in order to promote their evolutionary fitness. Put another way, I assume that a good deal of animal behavior is selfish — evolved because it allowed the ancestors of living individuals to survive better and leave more offspring than others of their species.

The presumption of selfishness is a helpful touchstone in my field. It provides a starting point when one is interpreting a new and unexpected behavior pattern. For example, if I notice a new soft call emitted by female loons during courtship, I am apt to hypothesize that this call might help mates synchronize their breeding activities so that each will be prepared to do its share of the incubation duties, once eggs are laid. (Such synchronization, which involves rising prolactin levels in the blood, has proved crucial to successful breeding in many species of birds.) So the presumption of selfishness can  be a useful prism through which to understand animal behavior.

A week ago, the folks at REGI learned of an event that pushed even my cynical viewpoint to the limit. Following a report from a lake resident, they found an injured loon on Metonga Lake, which is just south of Crandon, Wisconsin. After Linda and Kevin Grenzer captured the loon (pictured in Linda ‘s photo above) and the REGI team examined and x-rayed it, they learned that it had been shot at close range with a shotgun and had lead shot throughout its body. Despite efforts to save the unfortunate shooting victim, it died in their care. The story might have ended there, except that the loon was banded.

Since Metonga is outside of our study area — some 20 miles east of our southeasternmost lake — we do not know the lake at all. Sleuthing by Linda and me revealed that this oval 2000-acre waterbody supported two breeding pairs in 2018. According to the loon ranger, both pairs hatched chicks this year, although only one of the pairs fledged their two hatchlings. Most important, neither pair contained a banded individual. Thus, the shooting victim was not a member of either resident pair.

Some of the circumstances surrounding the tragic shooting make sense. As many of you know, breeding loon pairs become restless in September and October, often leaving their territorial lakes. Moreover, large, clear lakes like Metonga are favorite spots for wandering adults to visit, as they forage intensively and lay down fat stores to fuel their southward migration. So it is not at all surprising that a breeding adult from a neighboring lake — as we presume the victim was — would be found on Metonga. Finally, virtually all of the loons that we band that show up that far from our study area are females, because females are the more dispersive sex. (On average, females settle 24 miles from their natal lake, while males settle 7 miles from their birthplace.)

The identity of the shooting victim allows us to speculate about its tragic end. When I looked up the band colors and partially-obscured USGS band number that Linda provided, I learned that we had banded this female nine years ago as a chick on Bear Lake in Oneida County. We have not seen her since. The father and mother of this female were among the most approachable loons in the study area. (The male still holds the territory there, as he has since 2001 or earlier.) As Chapman student Mina Ibrahim showed a year ago, tameness (the minimum distance that a resting loon will permit a canoe to approach before diving) is similar between parents and offspring. So it is almost certain that the dead female was a tame individual, like both of her parents.

If our simple inference is correct, then this incident has exposed one hazard of extreme tameness in loons. While the vast majority of humans who approach loons closely are merely curious and would never dream of harming them, an occasional human might do so. It is easy to reconstruct the chain of events that led to the shooting. In the opening week of duck season, a hunter got an easy shot at a duck-like diving bird and took full advantage.

This analysis might well be correct, but it has one hitch. Loons are so well-known across the heart of their breeding range that they can scarcely be confused with ducks. None of the species of ducks that a hunter in northern Wisconsin would be looking to bag is patterned much like a loon. Furthermore, all duck species in the area are far smaller than loons and are prone to fly, not dive, when approached by humans. And since we know that the hunter blasted this loon from very close range, it is even more difficult to believe that the incident arose from a misidentification.

Call me cynical, but I believe that the hunter who killed this loon was not foolhardy, as generous and forgiving people might believe, but rather purposely wicked. Of course, this conclusion further erodes my opinion of other humans. What kind of person deliberately shoots a loon?