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?

Last year I wrote a blog post in which I concluded that late-hatching chicks returned at a rate no different from early-hatching chicks. I found the result surprising, as one would expect early hatchlings to have a head start in learning to feed themselves, honing their flight skills, and preparing for their first migratory journey. The photo and story I got from Linda Grenzer a few days ago has forced me to wonder if I need to collect more data on this question.

The breeding pair on Squaw Lake had an eventful year in 2018. Delayed, like all other pairs, by the late thaw, they initially nested along the shoreline near the boat landing. After a predator snatched both eggs off of the nest, they nested again not far away. This time they were more fortunate; the eggs hatched, but not until about July 22. When we captured the family on August 3rd, we found the chicks almost comically small — two little puffballs that did not approach the size of the many other juveniles we had encountered. Chicks are cute in their first few weeks, and we enjoyed observing them and handling them cautiously while giving the female a new set of bands.

Our delight at seeing the adorable chicks was tempered by the fear that chicks hatched so late would not mature in time to complete the southward migration. The fear is justified; parents must balance the energetic demands of their demanding offspring against their own need to maintain good body condition and prep for their autumn journey. Inevitably, adult loons spend progressively less time on their home lake in September as they forage intensively, molt into drab winter plumage, build up fat levels, and, in late October or early November, head south. This goes for parents and non-parents alike.

So it was not surprising to get a report from Linda that the Squaw adults had left their breeding lake, leaving their late-hatched chicks to fend for themselves. What was alarming was that one chick had chased someone’s jig, managed to hook itself above the base of the bill, and was no longer diving or foraging normally. Further evidence of its desperate condition was that it was not difficult to capture and weighed a mere 1750 grams — roughly 1 kg less than it should have at 9 weeks. Following an X-ray at Raptor Education Group, Inc. in Antigo, the chick was found to have swallowed a second hook from a separate encounter with an angler.

Since we have long since ceased our routine visits to study lakes, we can only speculate about the series of events that put the chick in this bind. Marge Gibson of REGI suspects that, without parents to help it satisfy its foraging needs, the chick was struggling to feed itself. In its desperation, the chick began to attack fishing lures until the hook in its cheek and weakness conspired to incapacitate it.

If Marge is right, and late-hatched chicks are sometimes left with too little feeding capacity to maintain themselves, then this pattern should show up in our data. Specifically, we should see fewer very-late-hatched chicks return as adults to the study area. This plausible scenario will fuel another round of data analysis…when I find time!

To end on a positive note, the angling victim is bouncing back at REGI and feeding voraciously. If you do not believe me, look at this video from the REGI website.

https://www.facebook.com/RaptorEducationGroupInc/videos/470615703434171/

If it continues to thrive, the REGI folks will face another challenge: what to do with a healthy juvenile, but one whose stay in captivity and recovery made flight practice impossible.

 

Recently, I made the kind of finding that gives scientists fits. It came about in the same manner that findings often do initially: a hunch.

Since I spend much of my life either working closely with loons or poring over data that describes their breeding success, I am in a good position to notice subtle changes that occur over time. Occasionally when out on a lake, I observe a breeding event and think, “Wow…..that did not happen in the old days!” Then I retreat to my computer, look at data from years past, and see if I am correct. I have to confess: in many cases, I am wrong.

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This past August, I noticed what I thought might be a growing pattern in breeding ecology. Mated pairs, it seemed to me, were less often rearing two chicks to fledging. That is, they were either hatching one chick and rearing the singleton only or hatching two chicks and losing one. At least that was my impression. In this case, field data confirmed my suspicion, as the above graph shows. The proportion of singleton broods has risen during the study. In three of the past five years, in fact, two-chick broods were quite uncommon, making up only 1/5 of all broods. Most of the pattern, moreover, appears to result from failure of one of two eggs to hatch, rather than loss of the second chick after hatching.

Faced with a puzzling and unexpected finding, I looked immediately at the usual suspects. Black flies, which have also been worse in recent years, are an obvious possibility. Flies harass incubating loons, reduce incubation times, and might reduce hatching success. In fact, I was convinced when I wrote our recent paper that black flies were the culprits. But then 2018 happened. This season featured a warm spring, a rapid die-off of flies, and very few fly-induced abandonments. So we could not blame flies for the low hatching rate of eggs in 2018.

What about the changing climate? As I have emphasized in a recent post, warm weather is projected to drive loons northwards; could it also be the root cause of the lower hatching rate? I looked to see if warmer May temperatures are correlated with reduced hatching, but they are not. (In fact, warmer temperatures are associated with a slightly higher hatching rate.) Likewise, precipitation might, in theory, reduce hatching rate. Again, years of higher May rainfall were not years of lower hatching success. I breathed a sigh of relief to learn that the lower rate of hatching does not (preliminarily) appear to represent the harmful leading edge of climate’s impact on loons.

Two possibilities remain. First of all, there is a small chance that the pattern is a statistical anomaly — that hatching rate is not actually falling, but that the result occurred by sheer chance. Scientists must always be circumspect about their results, and the statistical test says that there is a 0.6% chance that the finding does not represent a true pattern. (That is roughly the likelihood that you toss a fair coin 9 times in a row and get “heads” every time.) Second and more likely, some unknown factor is at work here. Might there be an environmental contaminant, picked up by loons, that increases developmental abnormalities in embryos or perhaps causes adults to cease incubation of the second egg prematurely? Might disturbance of incubation by humans be the cause of lower hatching success? These possibilities — and numerous others — generate testable predictions, and I will test them. In the meantime, let’s all keep our fingers crossed that the distinct decline in loon hatching success over the past 20 years is, after all, just a blip.

 

 

 

Humans are not good at thinking about the distant future. We are not alone in our short-sightedness. Living things, in general, are obsessed with the here and now and oblivious to what lies far down the road. There is a very good evolutionary reason for focusing on the present. Animals that succeed at surviving and protecting their progeny leave more young than other animals (in this case, hypothetical ones) preoccupied with what conditions might be like for their grandchildren and great-grandchildren. Animals that attend to their own survival and that of their offspring simply leave more offspring. Thus, natural selection can be said to favor animals that focus on the present — and animals within natural populations are chiefly descendants of parents and grandparents that cared for their own survival and that of their offspring. The short-term view makes sense evolutionarily.

Our very logical tendency to heed the here and now at the expense of the future has a limitation. Focus on the present adapts animals well to a stable environment, but leaves them poorly adapted to an environment that changes rapidly. Over evolutionary time, environmental change has generally occurred slowly enough to cause little problem for animals that live only for the present.

But humans have hastened environmental change. Anthropogenic changes have taken many forms, including introduction of invasive species, environmental degradation, and wholesale alteration of landscapes and vegetation. Perhaps surprisingly, many non-human animals have been able to keep pace with human impacts. In fact, some — crows, gulls and raccoons come to mind — have benefitted enormously from human activity. Others, of course, have become extinct, endangered or have seen their geographic ranges contract because of humans. We could quantify human impacts of each and every non-human species, if we cared to, and place each on a chart from least- to most-impacted.

Where on the chart would the common loon fall? Considering that loons are often viewed as the “voice of the wilderness”, one might suppose that they would suffer greatly from human encroachment. In fact, loons are hanging in there better than many other vertebrate animals. Knocked back in the middle of the 20th century, the common loon population has rebounded. Breeding populations are now generally stable or even increasing across most of the northern tier of United States. My study area in northern Wisconsin is typical; loons have re-colonized many lakes in the past few decades from which they had retreated. So loon populations are thriving despite extensive shoreline development, entanglements with hooks and fishing line, and increases in methylmercury levels, among many other challenges.

A new anthropogenic threat now looms that is more extensive and unrelenting than others that loons have faced. Climate change has already caused many geographic ranges of North American animals to recede northwards. A recent study showed that bird species differed greatly in their northward shifts, but that, on average, breeding ranges are marching northwards by over 2 km per year. We have a bit of an apples and oranges problem here; the bird species included in the study varied greatly in their diets and habitats. Some, no doubt, are highly dependent upon temperatures (and related factors like vegetation) for their survival; others are not. So it is difficult to project precisely how the geographic range of the common loon might be affected. But do this: take a look at Audubon’s animated depiction showing the contraction of the loon’s breeding range.

Two patterns are immediately clear from the animation. First, the northern Wisconsin loon population (and abutting populations in Minnesota and Michigan’s Upper Peninsula) exist on an isolated “finger” that projects southwards from the heart of the range, which lies in Canada. Second, the model paints a very bleak picture of the future loon population in northern Wisconsin. According to the model, loons are projected to be much less abundant in northern Wisconsin by 2050 and gone altogether by 2080.

Now, a word of caution. Audubon scientists have attempted to distill the climate down to two main factors: temperature and precipitation. On the basis of these two climatic factors, the current distribution of the species relative to these factors, and the projected future climate based on the report of the Intergovernmental Panel on Climate Change (IPCC), they have produced the  animated graph that loon enthusiasts like us find so disturbing. Their projection is likely to provide a crude estimate of the impact of climate change on loons, not a precise one. That is, loons are likely to cope with climate change better than most other birds — as they have other environmental threats. Then again, loons might be especially sensitive to climate change and retreat northward more rapidly than the study predicts.

Like many other humans, I am obsessed with the day to day. I have studied loons as if they would be around forever. I have battled to obtain grants to keep my study afloat, to publish my papers in high-impact journals, to hire diligent field technicians who would collect reliable data. Now, forced by changing environmental conditions to glance towards the future, I can scarcely believe that the animals that I have learned so much about and grown so fond of might be well on their way to vanishing from Wisconsin in my lifetime.

 

 

 

In my last post, I told only half of the story of the explosion of the Cunard family — the cheerful half. If you read that post, you know that, following the eviction of the Cunard male and abuse or neglect of the chicks by the evicter, one chick made a daring 1/4-mile trek across land to Hasbrook Lake and is now happily ensconced in that loon family.

The other Cunard chick was not so fortunate. In fact, following interviews of campers and the camp steward, we now know that a day or so before the eviction that led to the desperate dash of one chick to Hasbrook, its sibling had swallowed the live bait and hook used by a camper. As he described it to me, the fisherman panicked and did what most do when they have hooked a loon: he cut the line. I discovered the aftermath of this hooking. The thoroughly consumed remains pictured above suggest that the injured chick became weak, took refuge on shore (as seriously injured loons do), and was attacked and killed by an opportunistic mammal or scavenged after death. Its four leg bands confirmed its identity; the threaded line and fishing snap I found confirmed the cause of death. So the eviction that occurred on July 30th and 31st was actually the second unfortunate turn for the Cunard pair during the last three days of July.

We have discovered several such hookings during our study, despite the fact that anglers do not trumpet them. Perhaps we should take a moment to describe what to do when a loon takes your hook. The best outcome is removal of the hook by the fisherman. Removal of the hook gives the loon a good chance to survive the encounter. Cutting the line, on the other hand, frees the angler but leaves the hooked loon with a death sentence. A hooked loon (or other animal) on the end of a cut fishing line has to contend with a hook or lure that it probably cannot dislodge on its own. Its feeding impaired or prevented altogether, a hooked bird will probably succumb to starvation or predation resulting from its weakened condition. The second best outcome is to cut the line and immediately inform a local wildlife official of what has happened so that he or she can get help for the bird. In many cases, a hooked bird can be captured and de-hooked by me or someone else trained to do so. In other words, if you cut, don’t cut and run. Those of us who study and love loons will do our best to save one that is in trouble.

The Cunard chick’s death is a case in point. Had we known about the hooking, we would have had little difficulty re-capturing the chick and likely removing the hook as well. In that case, Hasbrook Lake might have ended up with four chicks rather than settling for three!

To those of us accustomed to looking at loons during the summer, the sight of an adult caring for three chicks — as in Laura Unfried’s photos from two days ago — is peculiar. Loons, of course, almost always lay only two eggs. If they are lucky, two chicks hatch. It is by no means certain that those two chicks will survive to fledging age. In fact, 47 of 61 breeding pairs we study have one chick, not two. So the spectacle of two adults caring assiduously for three young was startling.

Close inspection of Laura’s photo from Hasbrook Lake reveals another peculiarity: the central chick is much larger — perhaps 10 days older — than the other two chicks. (Note that the left-hand chick is entirely downy with a small bill, whereas the center one has the anterior part of its head coming into adult feather and has a bill nearly as thick as the parent’s.) The obvious size disparity told Eileen Lonsdorf, who reported the third chick three days ago, that her nicely balanced family of two parents and two chicks had been joined by an interloper.

How could a huge, healthy chick somehow get separated from its biological parents and join another family? Territorial behavior among loons guarantees that each breeding pair will nest and rear its young far from other pairs. The likelihood of a chick straying from its own family to join another — fortuitously or by design —

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seems remote.

One lesson that you learn if you do something for a long time is that rare events do occur. Chicks do very occasionally leave their parents and territory to join other families. We have noted two causes for such chick dispersal. First, starving chicks, especially beta chicks on small food-limited lakes that are being physically beaten by their alpha siblings, sometimes attempt to escape the abuse and find an alternate loon family nearby that will feed and protect them. Second, chicks that lose one or both parents to territorial eviction are forced to flee their natal territory and seek parental care elsewhere, if the adult that evicted a parent physically attacks them.

Solitary journeys by displaced chicks seeking new homes are desperate enterprises. One reason for this is that many lakes with loon chicks simply have no neighboring pairs with their own chicks that might be joined. Even if a displaced chick is fortunate enough to find a nearby pair with chicks, they are likely to be much older or younger than itself. If so, it is unlikely to be accepted by the new family. I vividly recall a case in 1999, when an abused beta chick undertook an astounding 1/2-mile trip across woods and roads from Benedict to Bug Lake in Vilas County, only to land with a foster sibling three times its size that beat it mercilessly until it perished.

Since the monster chick that joined the Hasbrook pair is a robust, well-fed individual, we could rule out that it fled to Hasbrook because of sibling abuse or lack of food. So we were left to conclude tentatively that a nearby territorial eviction forced this young loon to relocate. We pulled out a map to assess the possibilities.

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Immediately, we pinpointed Cunard Lake, which is separated from Hasbrook by a quarter mile of woods and bog, as the likely source of the wandering chick. Cunard, a regular study lake of ours, had two large, healthy, 5-week-old chicks at our last visit on July 25th. Yesterday, however, I found the lake empty of loons, except a single floater adult. The steward of the campground reported that loons had been chasing each other repeatedly across the water on July 30th and 31st, which indicated a protracted territorial battle. The absence of the territorial pair suggested strongly that the breeding male had lost the battle to a usurper and either died or been forced to abandon his territory and chicks. This tragic event, in turn, would have scattered the rest of the family and subjected the chicks to attacks by the new male owner.

Last night we captured the peculiar but close-knit family of two adults and three chicks on Hasbrook. It will require genetic analysis to be certain that the huge new chick on Hasbrook is a refugee from Cunard and the offspring of the displaced Cunard pair, as we surmise. But we have strong reason to believe that he is a most fortunate survivor of a desperate overland journey.

Few loons have endured the frustrations that the current Mildred female (“Taupe Stripe”) has. Initially captured and banded on Soo Lake in 2004, she reared two healthy chicks with her mate in that year. But each year since has yielded no offspring for this bird, despite consistent effort.

Taupe Stripe’s struggles started when she was evicted from Soo by a stronger female in 2006. Thus began an itinerant lifestyle: temporary settlement as a loner on Goodyear Lake and frequent intrusion into other lakes in the area, probing for an opening. In 2010, she finally secured and defended a breeding position on Maud Lake. Like other small, shallow lakes, though, Maud suffers from a limited prey base. Efforts by the loon pair there in the three years before her arrival were excruciating — hatched eggs followed by starvation of chicks in the 2nd week of life, the first week, and then the fourth week. Taupe Stripe and her two mates fared no better, failing to produce young in 2010, 2011, 2012, and 2013. She fell off our radar in late 2013 and 2014, but resurfaced in 2015 and 2016 — again, as a floater.

When day to day survival is a challenge, as it is for loons, you focus on the present. Taupe Stripe ultimately settled on Mildred Lake in early 2017. Unlike Maud, Mildred is a large, clear lake with a strong record of fledging chicks that hatch. Although she and her unbanded mate lost a small chick on Mildred last year, they have turned things around. Last week we caught Taupe Stripe, her mate (now banded), and their strapping six-week-old chick. Things were still looking good for the family upon my visit there today. And thirteen years of pointless wandering, frustration, and disappointment are forgotten.