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Yesterday, I heard the cheerful, buzzy calls of Japanese White-eyes* flitting about in the trees in my backyard. They are handsome and engaging little birds, but they don’t belong in southern California. They never lived here before humans did. As recently as ten years ago, white-eyes were quite difficult to find in the area.

A few weeks ago my wife, son, daughter, and I visited my ailing mother in Houston. On our first morning there, we were awakened by the incessant cooing of White-winged Doves*. They too are a striking species. The flashy white stripes on their wings and tails set them apart from the more familiar and homely Mourning Doves. Even the ceaseless calling of White-wings is rather pleasant. Don’t trust me on this; the abundant murmurings of this species inspired Stevie Nicks to write an entire song about them. But White-winged Doves have not always lived in the Houston area. I remember scouring trees around the Galveston County Courthouse in vain for this species with my mentor, Fred Collins, on a Christmas bird count a half century ago.**

Of course, while new species colonize new regions; well-established residents also vanish. In the Upper Midwest, the Piping Plover, a cute little shorebird, has recently become severely threatened. Though I have never seen a Piping Plover in all my years in Wisconsin and Minnesota, I do have experience with a second threatened species, the Black Tern. These agile fliers flit about marshy areas, plucking insect larvae and small vertebrates from the water and vegetation. They are appealing birds — with jet-black bodies that contrast tastefully with greyish wings and tail. But it is a longshot to find them in the Upper Midwest nowadays. What seemed a healthy breeding colony fifteen years ago on Wind Pudding Lake in northern Wisconsin — where we have always had a breeding loon pair — has disappeared altogether. It has been so many years since I last saw Black Terns on Wind Pudding that I have stopped looking for them there.

In short, my years as a bird-watcher have taught me that populations of birds change dramatically over time. Some species magically appear in new places, and other species disappear. I suppose it is my first-hand experience with the dynamics of avian populations that infuses my current research on loon populations in Wisconsin and Minnesota with such urgency. This is why I sweat the black fly season in May and June, worry about boat strikes and lead poisoning, and am in a bit of a panic over the recent loss of water clarity in the region. I have now seen — as I had not in 1993 when my loon work began — that birds can disappear.

* Photos by Natthaphat Chotjuckdikul and Ted Bradford from eBird.

** In fact, the picture is a bit complicated in the case of this species. White-winged doves occurred commonly in the southwestern U.S. 100 years ago, but the population was devastated by the expansion of the citrus industry. However, in the past three decades, the species has begun to nest in citrus trees and has come roaring back.

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On May 27th, the Little Pine-Dream Island pair was in dire straits. Hounded by black flies, they could not stand to incubate their eggs for more than a few seconds. At the time of our visit, the female foraged a hundred meters north of the nest, having been relieved of incubation duties for the time being. It was the male’s turn to cover the eggs. We watched helplessly as he mounted the nest, settled on the eggs for a few seconds, and then retreated back into the lake, his nape thoroughly inflamed with bites of flies that still savaged him.

Yet even the short dives he made after leaving the nest did not help. Whether it was because the flies’ mouthparts were inserted too securely into his flesh or their six legs grasped too firmly to his feathers, the male failed to dislodge his tormentors as we looked on.

We did not linger on the ill-named Dream Island territory. Although both pair members are exceptionally tame, we did not wish to be an additional distraction to them during their struggles. As soon as we had freed our prop from a stubborn underwater snag, we departed.

Plagued by boat problems and poor weather, it was a full five weeks before we were able to return to the Dream Island territory. Kate and Emily were thrilled to locate the pair with two healthy 10-day-old chicks bobbing about in the light chop of Little Pine. Evidently this sweet pair had the toughness and determination to achieve an outcome that, five weeks ago, seemed a dream indeed.

Video by Katherine Marthens.

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The beginning of the tale is heart-rending. A gosling is orphaned before hatching. A loon pair fails to hatch chicks of their own and, seeking to fill the void, sits on eggs they find near their nest. When these two desperate parties converge into a single — if nontraditional — family, they produce a heart-warming story*.

To see two species coexist despite 90 million years of evolutionary time spent apart is surprising. To see them not merely tolerate each other but become thoroughly interdependent, as parent and offspring, is truly striking. Such an improbable scenario makes one hopeful. This story suggests that differences between groups — even vast ones such as between geese and loons — can be overcome.

On the other hand, the sight of a gosling nestled comfortably on a loon’s back is also strange. It is a reminder — like exploding black fly populations, loss of water clarity, devastating storms, and the sudden abundance of wake boats — that the loon’s world has changed.

*Thanks to photographer Brad Thompson, who shared his beautiful photo.

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It is often said of field biologists that we resemble our study animals. I guess it is true. No, I am not aquatic. Nor do I subsist on a diet of fish, crustaceans, insect larvae, and the occasional mollusk. I did not even engage in a dangerous battle to secure my mate and territory. But, like loons, I enjoy being alone.

One of the joys of my profession is the time that I spend alone in a canoe, watching loons and taking in the beauty and simplicity of their lives. When your world is distilled down to watching the sky for other loons and bald eagles, chasing fish under water, and preening from time to time to take care of your feathers, life seems pretty straightforward. During those moments when I am with loons, their few concerns are all that matters. At such times, the headaches of keeping a major research project afloat, supporting a young field staff, repairing or replacing broken equipment, publishing scientific papers, and sharing engaging stories, photos, and video via social media vanish.

Loons would seem to gain even more than I do from avoiding crowds, especially at this moment. As a migratory species that winters along oceanic coasts, summers on northern lakes, and uses a variety of lakes and rivers in between, common loons appear at great risk from the current outbreak of highly pathogenic avian influenza. After all, waterfowl like ducks and geese, which share these waterbodies with loons, are known to be important hosts for the virus. Yet to date, loons seem to have avoided the epidemic of HPAI that has decimated other aquatic birds in the United Kingdom and eastern North America. How have loons dodged this juggernaut? Mostly by breeding solitarily, instead of gathering in dense breeding colonies on oceanic islands, where the virus spreads quickly via saliva, respiratory droplets, and feces.

Loons’ ability to avoid massive mortality events from HPAI is welcome news. After all, they already have had to contend this year with a late ice-out that has delayed their reproductive efforts and a higher-than-usual population of Simulium annulus, the black fly that singlehandedly makes May a miserable month. Yet some pairs have remained steadfast. At long last this week, several breeding pairs in Minnesota and Wisconsin Study Areas have hatched chicks, like the ones in the photo above from Ossawinnamakee Lake (photo by Keith Kellen). Maybe things are beginning to turn around!

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One of the pleasing sights of spring in the Northwoods is that of a territorial pair of loons, foraging side by side. No doubt the myth of lifetime fidelity of loons to their mates arises, at least in part, from the tight association of female and male loons at this time. Their apparent devotion to each other, their compulsion to remain together at all times, the touching plaintive wails that keep them in contact when they chance to become separated for a brief period all recall young human couples with limitless possibilities before them.

During the past three weeks in Minnesota and Wisconsin, I have seen many loon pairs foraging, resting, and preening together. It is truly heart-warming — to a degree. You see, once the territory resettlement period — the first three weeks after ice-out, roughly — has come to a close, loon pairs should be nesting, which means that humans watching out for “their loon pair” should see only one pair member or the other on the water.

Egg-laying marks the start of the nerve-wracking 28-day period of incubation where innumerable things could go wrong. A raccoon could wander by; an eagle could flush the incubating bird and feast on the eggs; a sudden downpour could turn a nest that seemed safely above water level into egg soup, cooling the eggs and killing the embryos. But one single cause of incubation failure has emerged as the single greatest threat to loon breeding success in Wisconsin and Minnesota in the past decade. The agent, a single species of black fly with a peculiar taste for loon blood, has recently surpassed even egg predation by raccoons and their ilk as a cause of nesting failure. When hundreds of black flies surround incubating loons and bite them mercilessly on the head and nape, the agony can become too awful to bear, causing the pair to abandon the nest. In recent years, black fly survival and persistence dictate how productive an entire loon population will be. It is that simple.

Yesterday, five of us — four members of the loon research team and a reporter for Minnesota Public Radio — ventured out onto the Whitefish Chain to mop up the few territorial pairs that we had not yet been able to visit this year. The trip was memorable for more than loons. An unexpectedly stiff west wind turned Middle Whitefish into a seething Lake Superior, forcing us to beach our motorboat prematurely at Boyd Lodge. (It took four Blizzards at DQ in Crosslake to help us move on after that hair-raising experience!)

Despite sketchy conditions, we visited nine new territorial pairs. We were thrilled when Kate spotted an incubating loon in a protected cove of Pig Lake. But that was the only territorial pair we scouted that was sitting on eggs. All others behaved as if the ice had just come off: they preened, rested, and foraged side by side. What would have been a cheerful sight in mid-May causes consternation now. Sixty to seventy percent of all pairs should be incubating eggs at this point in the season. Sadly, the featured image from Sibley-South depicts the situation in many of these lakes at present: two perfect golden-brown eggs — and loons nowhere nearby.

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There was no good reason for the Crystal female to defend her nest. I had confirmed the colored leg bands on her mate, and he was no longer the male with whom she had mated and laid eggs on the platform. Instead, he was the neighboring male from Halfmoon, who had left there under mysterious circumstances. Lake residents had reported a “ruckus” early this morning, and that ruckus had turned the 14-year-old male who had been her steady partner for 5+ years (lake residents had nicknamed him “Walter” — not after me but after the largemouth bass in “On Golden Pond”, which features loons) from an expectant father into a displaced, childless nonbreeder. Walter’s eviction meant that any ongoing reproductive attempt was over, as evicting males and females have no interest in incubating eggs or feeding young that are not their own. Yet the Crystal female — lake residents named her “Katherine” because of Katherine Hepburn in “On Golden Pond” — felt an inescapable attraction to the nest. As I approached to inspect the four defunct eggs on the platform, Katherine showed classic nest defense, swimming twice under my canoe. The evicting male from Halfmoon preened indifferently 100 meters away, as if willing to indulge his new mate’s obsession with her past nest but hoping she would get over it soon.

I witnessed a related behavior pattern on Swanson Lake just yesterday. There a mammalian predator (probably a raccoon, according to a camera study conducted some years ago by the Wisconsin DNR) had taken the two eggs that the Swanson lake female had laid in a second nest on the west end of the lake to replace those abandoned during the black fly period (see photo). When I arrived at first light, the female was alone, wailing intermittently, as loons do when their partner is not present. Forty minutes after I arrived, the male flew in, and he swam purposefully over to the newly-failed nest and climbed onto it. For three minutes he sat contentedly on the nest, as if all was good in the world. Then, he stood up on his legs and reached his bill downwards to turn the eggs, as loons habitually do. He seemed to put two and two together when he found no eggs to turn; afterwards, he sat only a few moments more before climbing down off of the empty nest and joining his mate in the water.

Despite 28 years of observation, I had never witnessed loon behavior that reflected slowness or inability to adjust to a new, stark reality — or perhaps I had simply not seen such behavior twice in so short a time, which made it impossible to ignore. As humans, of course, we have all behaved in such a way. That is, we have forgotten for a moment that some abrupt, fundamental change has occurred in our lives and mistakenly acted as we had before the change. Over a longer timescale, I find myself behaving so now. On each visit I make to a study lake in mid-June I expect to see young loon chicks or a pair late in the four-week incubation stage and on the brink of a hatch. But like the Crystal female and Swanson male, I find myself slow to adapt to a new reality — almost universal abandonment of first nests, many pairs without chicks or nests, and a great big dent in the breeding success of the population.

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What has been most striking about the dozens of loon territories we have visited in the past week has been how similar they seem to be to loon territories in early May. At that time of year, pairs have mostly recovered from the energetic stress of migration and have shifted their focus to breeding. With ice gone from the lake surface and perhaps a territorial challenger or two repelled, breeding pairs can search for a nest site, build a nest, lay eggs, and — if lucky enough to have a safe nest site or to avoid attracting egg predators to a risky one — jointly incubate them for four weeks until hatching.

Though the ice is long gone and challengers long since defeated, most loon pairs (over 90%, by our preliminary estimate) now face the same long slog of incubation they encountered a month ago. Having had their first nesting effort obliterated by black flies, these pairs now must start over from scratch. Thus, the video below depicts a common sight: a pair that has chosen a new nest site, started to lay eggs, and must work together to hatch chicks. These two birds, a 7 year-old male from Hasbrook Lake (background) and a 10 year-old female from Day Lake in Vilas County, seemed to contemplate this task with a degree of circumspection.

As nasty and harmful as black flies are, they are not as bad as egg predators. Flies are only really abundant for three weeks or so, whereas egg predators are always present. Loons behave as if they understand the time-limited threat that black flies pose. How? They commonly reuse nest sites that contain eggs from an attempt ruined by black flies, whereas they almost never reuse nest sites in the wake of egg predation by a raccoon or another predator. (Our recent paper describes this logical response to black fly abandonments.) Sometimes a males’ love of a nest site is so strong that he chooses it even though it still contains two eggs from the previous nesting attempt. In such cases, a loon nest contains two viable eggs from the renesting attempt and two duds from the abandoned effort weeks earlier (see the photo at the top, from Little Bearskin Lake this year). We often wonder how the sitting birds manage to cover and warm the eggs such that the good ones hatch.

In short, there is a new round of nests in the Northwoods of Wisconsin. During the past several days, as we have found pair after pair laying a second round of eggs and forging ahead in the hopes of raising chicks, it has raised my spirits. We will never look back at 2020 as a banner year for chick production, but the loons are not giving up.

 

 

 

 

 

 

 

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My new team and I are racing around the study area, still catching up to our banded breeding population. At each lake, we record the bands of the female and male, look quickly for any active or failed nests — only in obvious places — and race to the next lake to repeat the process: (“Ok…the female has a yellow band on right and is red over green on left? Good enough….let’s go!”.) The work is frantic and exhausting, and we are only halfway through. We are all so busy covering lakes that there is little time to reflect on what we have seen. I have trouble remembering what lakes we have even visited at the end of each day, so anxious am I to eat a meal and hit the hay for the next 5am wakeup.

Yet some patterns have emerged from our lake visits that remain lodged in my brain. It has been a dreadful first round of nests for most breeding pairs. Typical pairs in the study area abandoned their first nesting attempt three to four weeks ago because of the clouds of flies that descended upon them and have only just begun to renest or think about doing so. Based on what we have seen, it appears that 70 to 80% of all pairs could not stand to incubate the first clutch of eggs they laid in early to mid-May, making 2020 even slightly more devastating a black fly year than 2014, the previous worst year on record. Our study population has seen a steady slide in chick production over the past quarter century; 2020 will only strengthen that demoralizing pattern.

So you can imagine how it warmed my heart to hear about Linda’s loon pair (“Clune” and “Honey”), who managed to buck the trend and stick it out through all four weeks of incubation. At a time when the population as a whole is reeling, the assiduous parenting on display in Linda’s video below took my mind off of the population’s struggles for a moment and reminded me that good things can still happen.

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There was something distinctly wrong with the Buck male. He had never been tame. Indeed, he was one of those loons that made you work to see his leg bands on each hourlong visit. So, a few days ago, as I hefted my canoe down the steep paved road to the public beach that we use as our access to the lake, I knew I would face a challenge to get enough good looks at his legs to produce a convincing ID. But the male that foraged all around the lake with the usual female was well beyond a challenging ID. He was somewhere between highly vexing and impossible to identify. While the female gave me occasional good looks at her leg bands as I tracked her loosely during her foraging routine and seemed indifferent to my presence, her mate clearly avoided me and gave me no close looks at all. This was a reversal from two decades of past observations on the lake during which the female, not the male, had always been the tougher ID on Buck.

I paused at intervals to consider a change in tactics. But there is not much flexibility and creativity involved in IDing loons from colored leg bands. One simply approaches a breeding pair closely enough to see any bands on the loons’ legs but not so close as to upset the birds — and hopes for the best. This undertaking takes great patience and some luck, especially at times when black flies are out in numbers, as they are now, because loons shorten their above-surface time and seldom preen when hounded by flies. In an attempt to rally my spirits through distraction, I stopped tracking the pair after about an hour and circled the small island in the southeastern corner of the lake. Denying what was clearly a move borne of frustration, I told myself that taking my eye off of the foraging pair for a moment would allow me to search for a possible abandoned nest on the island. After all, I was weeks behind schedule in this first visit to Buck, and an experienced pair like the Buck pair should have long since started incubation.

No nest was evident on the island, but my effort to avoid for a moment the exasperating task of IDing the male ended up solving the puzzle of the male’s identity entirely. Draped over a fallen red pine on the south side of the island, I found the carcass of the Buck male that we had banded way back in 1999.

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It was sad to see silver over blue, red-stripe over red gone forever after watching him vigorously defend his territory for 21 consecutive years and never lose it — even for a day — in all that time. But it is the ultimate fate of every territory holder to meet a fitter, stronger, younger territorial opponent and bow to them. That is the essence of terminal investment in old male loons. The death of this oldest male in our study area (26+ years) now leaves the placid 24+ year-old Bear Lake male as the most senior representative of his sex. I am hoping the day on which the Bear male meets a determined, superior opponent in a territorial battle is still several years away.