longevity

on

Linda began to worry on April 18th when “Lucy” — the female from Muskellunge Lake whom we banded last year — showed up in a patch of open water with two other loons from the neighborhood. Male loons usually arrive a few days before females. Clune, the most famous loon in our study area, resident on Muskellunge since 2008, and Lucy’s mate, should have been back. Linda’s careful records show that Clune has appeared on Muskellunge before his mate in every year during the past 10 years except 2020, when his mate showed up two days before him.

It’s funny how, even as a scientist, I became attached to Clune. I remember encountering him back on Manson Lake in 1998. As his parents fished together in one cove near the boat landing, 4-week-old Clune and his sister dove together in a nearby cove. I tried to stay in contact with adults and chicks without approaching either pair too closely, but the chicks kept surfacing near my canoe and on the opposite side from their parents. On each such occasion, I paddled rapidly away and towards the lake’s center to restore the parent-offspring sightline. But neither parents nor chicks panicked, as I did, when my canoe split them. My canoe and I inspired the same degree of alarm as boulders, piers, and patches of vegetation.

Clune was precocious. He first appeared back in the study area as a two-year-old intruder on Hancock Lake. He wandered around for the next few years, as nonterritorial adults do. In 2003, he settled on Deer Lake, only 3 miles from Manson, where he had been raised. He and his mate produced chicks in 2003, 2004, and 2005 on Deer. Two of his sons from this period have followed in his illustrious webbed footsteps: one is the long-time breeder on tiny Virgin Lake; the other has cranked out offspring since 2014 as the territorial male on Squash Lake-Southeast.

Although we did not know it at the time, Clune’s breeding success on Deer was merely a prelude. Indeed, Clune and his second mate hit a slump on Deer from 2006 to 2008, failing to hatch a single egg. And so, as loons often do in the prime of life, Clune turned his attention to nearby alternatives. Muskellunge Lake was a chick-producer during the three years of Clune’s slump. Thus, in mid-June of 2008, Clune intruded into Muskellunge, battled the male territory owner, drove him off the lake, and settled on Muskellunge with the resident female.

Yet Clune seemed ambivalent about leaving Deer, where he had produced several chicks, and occupying his valuable new territory on Muskellunge. He faced an embarrassment of riches, it seemed. For three years, Clune and his mate bounced between Deer and Muskellunge. And Clune’s breeding slump stretched to five years.

At long last in 2011, Clune and a new female (“Honey”, as Linda came to call her) reared two chicks on Muskellunge. It was no fluke. The chicks of 2011 began one of the most impressive runs of breeding success we have ever seen in northern Wisconsin. Between 2011 and 2021, Clune and Honey hatched chicks in every single year and raised 13 chicks to adulthood. (Clune added a 14th chick in 2022 with a new mate, Lucy.)

What set Clune and Honey apart from other pairs was their dogged determination as incubators. 2011, 2014, 2017, 2019, and 2020 were years during which 27% to 90% of all loon pairs in northern Wisconsin abandoned their May nests owing to severe black fly infestations. Clune and Honey sat tight throughout these dreadful years, tolerating hours of motionless incubation while flies sucked their blood at will. They did not abandon a single nest. Consider this feat for a moment. Both pair members must be committed to warm the eggs for several hours at a stretch in order for a nesting attempt to succeed. While loon pairs throughout the study area abandoned their nests and hatched few chicks for a decade, Clune and Honey thrived.

Despite his sterling breeding record, it is Clune’s affability that I will miss the most. He seemed to sense that humans in canoes and kayaks meant him no harm. Perhaps he even got to know Linda and me, since he had seen us so often throughout his life. It certainly seemed so at night when he hardly budged as we gently threw a net beneath him each year, lifted him out of the water, weighed him, and replaced his worn bands.

There is a new male on Muskellunge this year. (See Linda’s featured photo of him yodeling, above.) He is “Yellow over Copper, Red-stripe over Silver”, a 12-year-old hatched on Prairie Lake who has lived and attempted to breed on nearby Halfmoon and Clear Lakes for the past three years. Like all males on new territories, he will probably struggle on Muskellunge to find a nest site where he and his new mate can hatch eggs. Maybe Yellow over Copper will beat the odds, take advantage of the plentiful breeding habitat on the lake, and raise a chick or two in his first year. I am keeping my fingers crossed for him. He is a fairly tame loon and a vigorous defender of his new territory. I knew his parents for many years on Prairie and have a good feeling about him. But he is not Clune.

on

I have often trumpeted the high survival rate and steadfastness of adult females. Female breeders are masters at perceiving when the tide of battle is turning against them, fleeing from their stronger opponents, and living to breed another day on another territory. Females are survivors.

Male loons, it seems, are not so clever. Perhaps because males control nest placement and, therefore, gain critical familiarity with territories that females do not, males value their knowledge and ownership of a territory highly and seem to fight too hard to hold familiar territories. They often lose their lives as a result.

Against this backdrop of pragmatic, long-lived females and reckless, short-lived males, our capture of a certain male a few nights ago was particularly striking. “Silver over White, Blue over Blue-stripe” first settled on clear, 221-acre South Two Lake in 2002 — when my current field interns were infants or toddlers. The next year, however, Silver over White was booted off of South Two. He settled ultimately on the the Lake Tomahawk-Thoroughfare territory. Thus began one of the most productive runs of chick production we have seen in the history of the Loon Project. Silver over White and two different females reared at least 12 chicks over seventeen years. Moreover, we could hardly help loving this affable male, who year after year nested in plain view and within a stone’s throw of the busy channel that connects Lakes Tomahawk and Minocqua. Dodging indifferent motor-boaters, the Tomahawk-Thoroughfare pair each year led their tiny chicks out of this dangerous channel to the relative safety of the big water of northwestern Lake Tomahawk.

This spring, Silver over White’s second mate apparently did not return. Not missing a beat, he paired with the former female breeder on tiny Schlect Lake — whose mate was also missing — and again nested in his favorite spot along the thoroughfare. Fortune did not smile upon the pair this year, and they did not hatch chicks. When it became too late to nest, both Silver over White and his new mate seemed destined to ride out the year loafing and foraging on Lake Tomahawk.

But Silver over White, who at 25 years of age was well past the time in life that most males look to take a territory by force from another male, was not satisfied with that laidback plan. Instead, he returned to South Two Lake — where we had not seen him since 2003 — and apparently evicted its young owner. (We caught Silver over White a few nights ago, as the featured photo shows.) Silver over White’s feat was especially impressive, because his territorial opponent had two three-week-old chicks and no doubt fought viciously to protect his territory and young.

I returned to South Two today, in daylight, to confirm the territorial situation there. (Marge and Gerry Perner were kind enough to take me out in their pontoon boat.) The scene was chaotic: seven loons socialized distractedly, coming together, splitting apart, and converging again. One fact seemed clear though; Silver over White and a new female — a seven-year-old hatched on Silver Lake, near Minocqua — are the new territorial pair. The freshly-evicted male was nowhere to be seen; we hope he is still alive somewhere. The old female, who was rearing two healthy chicks with the evicted male a few days ago, appears also to have lost her breeding position. As she did two years ago, when she settled on South Two after losing her mate on Little Carr Lake, this female will have to bounce back and find a new place to breed.

Silver over White’s remarkable ability to win a battle against another territorial male at 25 raises two exciting questions. First, how can this male defy the odds and make an aggressive, risky play for a new territory, when most males his age are merely hoping to hang onto their territory for another year or two? Second, it is astonishing and unprecedented to have an adult breeder return to a lake that s/he had been away from for more nineteen years. (The longest stretch of time that a loon had been a breeder on a territory and then had returned to it after eviction had previously been six years.) Did Silver over White try to take over South Two because he still remembers safe nesting sites there and thus knows that he can quickly resume a successful breeding career on the lake? If so, his seizing of his old territory suggests that loons have impressive long-term spatial memory.

I wonder why I have been rooting so hard for Silver over White. I suppose it is because — at a time when I have turned rather silver over white myself — I find it quite inspiring to see his dogged determination to be productive despite the passage of years.