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It’s like deja vu all over again at Muskellunge Lake this week. Thanks to Linda Grenzer’s vigilance, we have learned that the productive and photogenic pair on Muskellunge came back together this week — just as they did about this time in 2014! As Linda’s photo shows, “Clune” and “Honey” (Linda’s names for the banded pair) were a bit wary of each other at first. This shyness should not be surprising, as they have both lost their breeding plumage and donned winter attire. According to Linda, though, they rather quickly recognized each other and paddled off contentedly together. Apparently after 6 years of being together, and rearing of 10 chicks to fledging, familiarity with your partner involves more than just feathers!

We have very poor information on the behavior of territorial loons in the fall, so we can only speculate about what it means that an established pair seems to come together routinely just before fall migration. As a behavioral ecologist, I am inclined to interpret such meetings as more calculating than romantic. I cannot resist the temptation to view such a meeting as a final patrol of this precious breeding lake by its owners to ensure that no intruders have tried to put down roots in hopes of claiming Muskellunge in 2017. To any such pretenders, the presence of a tight pair late in the fall would signal that the territory was not available without a costly battle. But that is just speculation.

I must apologize for taking so long for this post; I have been busy exploring loon survival patterns. Indeed, I have been able to sharpen our view of senescence considerably. Some of you will remember that I announced several months ago that males senesce, while females do not. While I was excited about the apparent finding, it seemed to defy logic and begged for elaboration. With the return rate data from 2016 in hand, I was able to reanalyze survival patterns of both males and females banded as adults on territory. As is becoming all too common, I must eat crow. It is still clear that males senesce — those between 5

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and 19 years of age survive at a rate of 94% annually, while those 20 years and older survive at an estimated rate of only 71% (see graph, above). That is a steep drop-off in survival rate, indicating clear senescence. But the newer, more robust dataset has shown that females are not immune to the march of time. Indeed, 5 to 19 year old females survive at about 94%, like males; 20+ year old females fall off to 79% survival (see above graph). It is a tad deflating to realize that the world was more complicated than I had reported before, but also a relief to know that — and don’t take this wrong — females are not immortal!

One more tidbit relating to senescence. I have been able recently to complete a survival analysis of loons that were banded as chicks in the study area or nearby. (We call these birds “ABJs”, or “adults banded as juveniles”.) The most striking outcome of the ABJ survival analysis is, again, a difference between females and males. In this case, male survival plummets from 94% at ages 4 to 14 to 78% at ages 15 to 18 among both territory holders and floaters (adults without a

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territory; see graph above). In contrast, females show steady survival of about 92%, regardless of age or territorial status (see above graph). Males, in addition, suddenly begin to lose their territories to eviction at the rate of 38% when they turn 15 years old, while females only suffer eviction at a rate of 12% from 4 to 18 years of age. So here we have evidence that males not only die at a higher rate once they turn 15, but that they also become vulnerable to being booted off of their territory.

If you have paid attention closely through the litany of data I have dumped on you, you have probably noticed one final pattern: the ABJ analysis showed senescence occurring in a younger age class than did the analysis of territory holders! That is, male ABJs senesce at age 15, while male and female territory holders show no senescence until age 20. This is a brand new finding that I am still puzzling over, but there is an obvious explanation. Territory holders are likely to comprise a fitter class of adult loons that have shown their ability to fight for and defend territories and also rear chicks. In contrast, ABJs are only chicks that have survived to adulthood and returned to the study area. They are not “battle-tested” by having claimed a territory and bred there. Much later senescence among the evolutionarily fittest set of loons in the study area should not surprise us.

I am not ready to stake my reputation on this latest finding, but if it holds up, it dovetails nicely with one of the long-standing debates among ecologists concerning territorial breeders and floaters. We have long wondered whether territory holders should be regarded as floaters who got lucky and found a territory, or whether the two groups are, in fact, distinct classes in terms of fitness. The steep drop off in survival of male floaters in loons, compared to male territory holders, would strongly support the latter interpretation.

If you have been floundering lately, as I have, let’s gain some perspective by considering the plight of the Silver Lake loons. The pair’s struggles began in mid-May, as black flies thwarted their efforts at incubating a first clutch of eggs. According to Pat Schmidt, who watches the pair carefully throughout the breeding season, incubation proceeded normally during the nighttime — cool temperatures kept the relentless pests at bay. But the marked female and male were unable to stay on the eggs during daylight hours, when black flies were active and biting. On again, off again incubation finally gave way to abandonment during the last week of May, but the pair reset themselves quickly, adding two additional eggs to the two they had earlier tried and failed to hatch. Despite the cumbersome task of warming four large eggs simultaneously, the birds produced a chick at the very end of June. Their fortunes seemed to have turned.

The greatest risk faced by a breeding loon pair with a chick is our national bird. Bald eagles nest on tall white pines along lake shores and are a frequent sight over lakes. Indeed, eagles are such a routine part of the scenery on the lakes that loons often deign to wail at them as they pass overhead. Eagle fanciers might try to convince us that these raptors even purposely lull loons into a false sense of security with their constant, mostly innocuous flights nearby so that they can occasionally strike at loons suddenly with deadly purpose. An opportunity for such a surprise attack might occur when an eagle appears just above the tall trees at the lake’s edge as a week-old chick’s parents both happen to be underwater diving for food. Perhaps it was such happenstance that allowed an eagle to carry off the Silver Lake chick on July 2nd. In any event, eagle predation brought the breeding efforts of the pair to an unsuccessful close this year.

The sting felt by lake residents at the loss of the chick had begun to abate by July 18, at which point the territorial female, “Copper” (named for one of her plastic leg bands), found herself in a desperate battle. She was beaten badly, chased across the water, attacked from below as she rested on the lake surface, and finally forced to take refuge on land to escape further damage. By the time the violence had ceased, Copper had to be carried, helpless, to the Northwoods Wildlife Center. She died there a few days later.

As I have made clear in numerous posts, males are the ones that battle dangerously (apparently because of senescence) in most cases. So how do we explain the latest Silver debacle? An oddity concerning contestants might offer a clue in this case. Copper, who had reared chicks on Silver in 2014 and 2015, had battled repeatedly for ownership over the past several years with her bitter rival, “Mint”, the previous Silver female and mother of the chicks in 2010 and 2012. Even after losing the territory to Copper in early 2013, Mint was a frequent intruder into Silver Lake. Hence, both females had raised chicks in multiple years with the male, and both were highly motivated to vie for control of the territory. In addition, banding records indicate that Copper and Mint were of very similar size.

Now to game theory. If an animal encounters a long-lived opponent with which it is very closely matched in fighting ability but happens to get the upper hand at some point, it might then pay for that first animal to press its advantage and even kill the opponent. Why? Because our research has shown us that closely-matched pairs of females, like Copper and Mint, often give each other fits. Two females on Heiress and two others on Oscar-Jenny were so close in fighting ability that they traded off ownership of those territories over many years, each female hindered in her breeding efforts because of the constant interruptions of the other. The result was poor reproductive success for both rivals. Although there is enormous risk involved, it might occasionally pay for females to exhibit the vicious battling we associate with males. Specifically, a lightning strike to finish off your archrival might sometimes be worthwhile to avoid a chronic, destructive feud.

 

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In many recent posts, I have emphasized a certain theme: male loons begin to die off at a rapid rate after age twenty, while females linger on. Part of the reason for this contrast is the nature of territorial contests in each sex. Territorial males fight hard in attempting to hold their breeding position on a lake and commonly die in territorial battles. With rare exceptions, territorial females survive eviction from a territory, move to an unoccupied lake nearby, and resettle on a new territory when opportunity permits.

While the escalation of male territorial battles is interesting in itself, it also impacts the composition of the breeding population. Specifically, adult male loons’ propensity to die frequently in battle skews the sex ratio towards females in the breeding population.

These excess females are “floaters” — adults capable of breeding but prevented from so doing by the lack of a mate and/or a territory. Floaters are the loons that one sees living alone on small lakes, drifting about aimlessly on large lakes, and intruding into territories from time to time to confront breeders. A large proportion of the loons that gather in flotillas of five adults or more during July and August are floaters. Floaters can be thought of as “hopeful breeders”; that is, they are always ready to settle and breed with a mate and territory, if they can find one. The excess of female floaters means that there are always far more of them looking to settle and breed than there are male floaters able to pair with them. In effect, males are snapped up by females as soon as they become available for breeding.

In May of this year, we re-encountered one of our veteran breeders, “Silver over Blue, Green over Orange” (or “S/B,G/O”), whose breeding history illustrates the striking contrast between males and females brought about by male-biased mortality. S/B,G/O was first captured and marked as an adult in 1997 on Dorothy Lake, where she raised two chicks with her mate. Her mate was evicted in 2001 and died either during eviction or shortly afterwards. But she lingered on. When an opening became available in 2002, she settled and nested with a different male on Hasbrook Lake, just a few miles to the northwest. Having failed to raise chicks on Hasbrook, S/B,G/O (now at least 14 years old) evicted the female breeder on Hodstradt in 2004, paired with a third male, a six year-old, and reared four chicks there during the next three years. She followed this young male to Horsehead Lake in 2008, when he was driven off of Hodstradt, and the pair fledged 3 more chicks over the next four years on their new lake. When the male was evicted yet again in 2013, S/B,G/O traded experience for youth and found a new six year-old male as a breeding partner. We breathed a sigh of relief when she broke up with this youngster after a year together, as he was unfortunately her son from Hodstradt! Then 23+ years old, S/B,G/O again became a floater, forced to return to the breeding grounds in 2014 and 2015 with no clear prospects for breeding.

I have become attached to the birds in the study area, so I was delighted to find S/B,G/O back at Hodstradt in May of this year with her fifth recorded mate. At 26+ years of age, she is perhaps fortunate to be paired again. Her mate this time: a four year-old hatched on Clear Lake. We observed no breeding attempt by this new pair – only a small percentage of four- year-old males that settle on territories actually nest – but it is likely they will nest in 2017.

As a human, I like to think of S/B,G/O’s life as a lesson in resilience – the dogged refusal of an animal to forsake breeding despite repeated setbacks and advancing age. But, as a behavioral ecologist, I think of this female more as a striking example of how animals adapt to maximize their breeding capacity regardless of the breeding environment they face. By the way, S/B,G/O is not the only female in our study area who has continued to breed despite frequent changes of partner. S/R,O/O, another 26+ year-old from Swamp Lake that we recaptured a few nights ago (see photo with Eric), has gone through at least 5 younger mates during her 20 years of breeding there. Clearly the pairing of tough, old females with much younger males is – as my daughter says – a thing.

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He doesn’t look it, but this male from Townline Lake, just outside of Rhinelander, is at least twenty-seven years old. He is among a dwindling few males from among those we banded in the mid 90s. This bird was banded in 1994, at which point he was certainly at least five years old, which means that he was hatched in 1989 or before. Thus, twenty-seven is a minimum estimate for his age.

The age of “Silver over Red, Orange over Green” (as I call him affectionately) is not his only remarkable attribute. What sets this individual apart from most others is his ability to hold onto his territory year after year while fledging healthy chicks. (Below, he relaxes near his mate and two strapping chicks from 2016.) A successful common loon is not only good at locating safe nest sites and defending and feeding young. A breeder that wishes to

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reproduce successfully must confront intruders that land in the territory without warning throughout the breeding period.

Intrusions are especially frequent during the chick-rearing period. A common scenario plays out as follows. Early in the morning, a male is diving for food, while his two chicks track his progress from the surface. Each time he surfaces, the chicks rush over to him, snatch food from his grasp, and nibble relentlessly at his bill, neck and chest, signaling their unquenchable appetites. On one occasion, he surfaces holding a small yellow perch, only to find five adult loons in flight above his lake. He drops the fish, gives a short barking call, and the chicks dive and head to the nearest shore. The male too dives but surfaces near the middle of the lake, drawing the now-descending intruders to himself. Three quarters of an hour later he has driven off the intruders, thanks in part to a lunge and point yodel that caused his five visitors to scatter and tremolo. Shortly afterwards his mate returns, and both parents forage for the chicks. The family suffers no further disruptions until the evening, when another group of three nonbreeders circle and land, causing yet another brief skirmish.

Considering that a large pool of territorial intruders are constantly sizing up the resident male or female of any successful territory for an eviction attempt, it seems remarkable that residents are able to hold on to their territories for even a single year. Yet Silver over Red, Orange over Green has put together a string of 23 years of straight ownership, the only blemishes a half-year in 1996 and another in 2003, when he was briefly deposed. He has fledged 20 chicks during his breeding career with four different mates. This male is not the only resident with an impressive resume. A female on nearby Langley has fledged 17 chicks on that territory since 1995, while the O’Day female has been on territory since at least 1997 and has produced at least 16 full-grown chicks during her breeding career.

But female loons are survivors. Females enjoy a high rate of survival and no detectable senescence well into their twenties. Males, on the other hand, hit the wall abruptly at age 20; almost half of all territorial males of age 20 will perish before the subsequent year. So when we see a male who defies the odds, like this one, it is worth looking closely to see if he possesses an attribute that sets him apart. As a scientist, I am loathe to draw conclusions based on a sample of one. Colleagues in my field would dismiss any such conclusions out of hand. But today Nelson, one of my Chapman research students this year, reported that Silver over Red, Orange over Green is the tamest bird we have ever measured in the study area. So let me invite ridicule by advancing a very preliminary hypothesis. Perhaps the key to lifetime productivity in a habitat rife with human recreation is picking one’s battles carefully. Maybe by ignoring the inquisitive, well-meaning primates in their watercraft, this male has been able to conserve his metabolic resources for provisioning young and driving off pesky intruders.

Why would a breeding pair of loons — which has made an enormous investment in defending a territory, finding a nest site, incubating their eggs for almost a month, and then rearing their chicks — leave them alone? Such behavior seems reckless, almost dysfunctional. Yet loon pairs commonly “desert” their offspring for periods of hours, while they themselves visit neighboring lakes. During such times, of course, chicks are left to cope with all manner of predators and other dangers without parental assistance.

The leaving of chicks behind by parents does not occur willy-nilly. That is, not ALL chicks are deserted, only those that have reached at least four weeks of age. Some chicks, like those I watched on O’Day Lake this morning, are highly alert to their surroundings, like adults, and capable enough hunters that they are already providing over half of their own food. (Note the expert-looking dive by the chick in the video.) One can imagine that temporarily leaving behind chicks of this age does not carry huge risks. At six weeks of age, chicks can detect and flee from eagles, when necessary. So perhaps the risk of leaving your chicks to fraternize with neighboring adults is not great.

Still, temporary chick-desertion surely carries some risk. If the choices are remaining on your territory with your chicks versus departing to a nearby lake to visit with other adults, the first option is clearly the safer one. The only conclusion to draw from what appears to be rather reckless socializing by pairs with chicks is that they must gain something nontrivial from doing so to compensate for the small risk that their chicks will be lost during their absence.

Their are several possible explanations for parents’ trips to neighboring lakes. One hypothesis maintains that parents encounter and become familiar with neighbors whom they might have to battle later for a territory or with whom they might pair in the future. If so, recognizing and learning about other adults might provide for more effective fighting or breeding. A second idea is that parents leave their chicks in order to forage on lakes other than their own so as to maintain robust food levels for the chicks. Thirdly, temporary desertion of the chicks might constitute part of the weaning process; chicks often beg incessantly when with their parents, and perhaps chicks must be without parents to begin foraging effectively on their own in preparation for adulthood. A fourth explanation is that parents, which are conspicuous to other adults owing to their bright plumage, desert their breeding lakes in order to avoid giving away the fact that they have chicks. (Behaving this way might reduce the likelihood that a young nonbreeder could target the territory for eviction, since we know that intruders use chicks as an indication of a good territory.  ) If this explanation is correct, then parents are essentially trying to “decoy” intruders away from their own lake by visiting a neighboring territory nearby. The hypothesis is plausible, because: 1) intruders are strongly drawn to other adults in the water, and 2) intruders appear to find chicks only after seeing and approaching the chicks’ parents.

One final curious behavior seen in loons and chicks provides partial corroboration for the “decoy hypothesis”. When faced with an intruding loon flying over their lake, adults and their chicks dive and scatter. That is to say, adults and their chicks make every effort to hide from intruders by diving and spreading out in the lake, which complicates discovery. If loon parents are desperate to hide their chicks from intruders, what better way to do so than by flying off to other lakes near their own — and thus using their conspicuousness to draw intruders to those lakes — and leaving their cryptic chicks at home, where they will most likely escape notice from the air.

The decoy hypothesis is complex. Its crux is that loon parents are protecting their own future breeding prospects by taking a slight risk with their current chicks. In time, we will be able to determine if parents that practice short-term chick desertion enjoy longer territorial tenure. If so, this will be a stunning example of effective long-term planning in the animal kingdom!

 

Mina caught the tail end of the battle. By the time he arrived for his observations, the territorial male on Blue-Southeast was on his heels. No doubt shell-shocked from a beating he had received from an aggressive four-year-old male that had lurked in the neighborhood for two years and was making a play for territory ownership, the territorial male beat a hasty retreat, actually flying off of the lake with another intruder.

The strategic retreat of the territorial male left his mate in dire straits. Without another parent to engage intruders, the female alone had to defend the week-old chick from the aggressive onslaught of the four-year-old male. The situation was hopeless, the suspense only fleeting. The young male quickly discovered the chick and — in the grisliest moment we have observed while studying loons — snatched the chick out of the water and carried it for a time while pursuing the retreating female. When he dropped the lifeless youngster, it was over.

When the shock wears off, we will one burning question about this episode: “Why is Blue-Southeast the site of such frequent territorial controversy?” Can it be coincidence? One must never be hasty to rule out chance, but I think that is not the explanation here. Rather, evictions of the territorial male in 2015 and the same individual again this year resulted from his relatively poor fighting ability. Intruding loons are adept at sniffing out weakness in territorial residents. When a breeding male or female is unable to drive competitors forcefully off of the lake, intruders congregate, leading to further confusion and attempted evictions, in a disheartening positive feedback cycle. The Blue-Southeast male, while a capable parent, has often encountered intruding males that he could not drive off of the territory in years past. It is quite possible that his troubles in 2015 occasioned more territorial challenges in 2016 by the same set of challengers.

I am by nature a rather negative person, always quick to point out the downside of every cheery situation. But I see one bright spot here. If the usurper of the territory and killer of the chick becomes the territorial male, he would appear to be a strong and aggressive individual and one likely to defend the territory with greater success than his predecessor. This 2012-hatched product of nearby Bolger Lake would be a record-setter too, since he would be the youngest male ever documented to seize a territory by force. (Most young males, like very old males, settle on vacant territories rather than fighting their way onto occupied ones.) I wish I could offer more meaningful solace to Blue Lake residents, who will be dismayed at today’s turn of events. The best I can do is to suggest that the future for the Blue-Southeast pair is likely to be brighter than the recent past.

 

 

 

 

 

 

 

 

LMG_8014 Fall Molting Loon

Some months ago, I reported with excitement that loons that leave their first territory — usually because they are evicted from it by another loon — have a strong tendency to settle on a second territory with similar water clarity to the one they left. It was a striking finding and one that would have added a fascinating story to ecologists’ limited understanding of how animals choose where to settle once they reach adulthood. That pattern, which initially seemed a robust one, has turned out to be trivial.

Let me explain. When loons are forced to shift from one territory to another (or do so voluntarily), they typically settle on a second territory very close to their first one. Often they move to the lake next door or even settle on a different part of the same lake. What we thought we had found was that those “resettlers” carefully choose to settle on second lakes of similar clarity to their first lakes. But such a pattern is tricky to show conclusively. In order to do so, one has to determine how similar 2nd lakes would have been to 1st lakes if loons had settled at random and compare the actual pattern to random settlement.

The problem we ran into was spatial autocorrelation. Spatial autocorrelation simply means that within a large area, two points that are physically close to each other resemble each other more closely than two points that are farther apart. It turns out that lakes of similar clarity tend to be clustered. That is, if one lake is clear, then its neighboring lake is likely to be clear also. The same is true of murky lakes. So while we thought that loons were purposely choosing to settle on second lakes of similar water clarity to their first ones, they were merely settling on lakes near their first one which happened to be similar in clarity to their first because of proximity. In other words, we have no evidence that choice of lakes is non-random.

It took us a long time to discover the error. In fact, Mike Palmer and I had written up this finding and submitted it for publication before we realized — after running a new analysis requested by a reviewer — that spatial autocorrelation was solely responsible for our result.

Naturally, I am feeling a bit like the female on Muskellunge Lake, photographed recently by Linda Grenzer. A month or so ago, this bird and I were on top of the world — she because she and her mate had just fledged two chicks (a bumper crop for loons) and was in her showy black and white formal attire; I because I had an exciting finding that I could not wait to share with colleagues. Now the luster of the recent past is gone. The female’s chicks have dispersed to fend for themselves, she has lost her gaudy summer plumage, and she is about to resume survival mode during migration and winter. I have lost my thrilling discovery and will have to pick myself up, dust myself off, and attack some other scientific question.

Luckily, the Loon Project supplies an endless string of questions. One that tantalizes me at the moment: do chicks that fledge and leave their natal lakes to forage on other lakes nearby favor those that resemble their natal lakes? Such a result, if it occurs, would dovetail nicely with our finding that the first lake a loon ever settles on as an adult (at 4-7 years of age) tends to be strongly natal-like in size and pH. This result (he adds quickly) is not confounded by spatial autocorrelation, because first lakes tend to be far from natal lakes. At any rate, I shall let you know what I find.

When loon biologists measure reproduction, they often count chicks older than five or six weeks of age as having fledged. This is reasonable. Even though loon chicks remain dependent upon their parents for 11 weeks or more, almost all chick mortality occurs in the first few weeks of life. If a chick makes it to five weeks, it is almost certain to make it to adulthood.

Not so during this past week. As the unpleasant photo by Dan Pagel shows, one of the the Blue-Southeast chicks died quite violently several days ago after a sudden attack by an adult. Based on the photo and the swiftness of the death, we suspect that severe heart or liver damage caused the death. Since Dan was a few hundred meters away when the murdered Blue-SE chick IMG_3960vicious attack occurred, he was unable to identify the perpetrator. Regardless of what loon committed this act, it comes as a shock. The departed chick was over twelve weeks of age, healthy, and off by itself feeding when it fell victim to the brutal assault. Twelve weeks is much older — I believe as much as eight weeks older — than we had ever observed a chick to be killed by a foreign adult. In light of the tempestuous territorial scene at Blue-Southeast recently, it is tempting to view this chick as a casualty of the conflict that caused its father to lose his territory. Certainly, the new, unmarked male that had taken over on Blue-Southeast and had already been observed to peck the chicks in his first weeks of ownership is a suspect. A second possibility is that the chick carelessly strayed into the west territory on Blue Lake and was attacked by a member of the West pair for territorial reasons. But territory defense is scant and subdued at this time of year, so that explanation is problematic.

I was still coming to grips with the events at Blue Lake a few days ago when I received a second piece of news, equally discouraging. One of the chicks at Buck Lake, near Rhinelander, had died. The cause of death in this case is less clear; the chick’s leg became injured a few weeks ago — a lake resident reported that a snapping turtle latched onto it! — and the chick was not able to move about effectively afterwards. Like the Blue chick, the Buck chick was far past fledging age, having reached 11 weeks.

What can we conclude from the co-occurrence of two deaths in very large and healthy chicks? I think these two unfortunate events simply remind us that, while chicks that have reached near-adult size are far more likely than 2-3 week old chicks to survive to adulthood, they are still young animals. As we have reported in a scientific paper, loons suffer a higher rate of mortality during their early years. Adult loons have had years to hone their ability to feed themselves and cope with environmental hazards, including conspecific attacks; youngsters are still getting it down.

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Recently, Eric, a second-year team member who is experienced at reading colored leg bands, ran across our oldest loon. This male, evicted in 2007 from Little Bearskin Lake, has been cooling his heels in Bearskin Lake since his displacement and shows no indication of regaining a territory. “Blue over Silver, Yellow only” produced 14 fledglings during his breeding career, 7 of which also bred in the study area. That level of chick production places him among an elite few in our study population.

Blue over Silver, Yellow only’s age sets him apart from all others. He is at least 28 years old, because he was banded as an adult breeder, which means he was at least 4 in 1991. He may be in his 30s. But a number of other loons that we have marked during the study approach this male in age — and three exceed him in productivity. The female on Upper Kaubashine (“Silver over Yellow, Red over Green”), for example, is 27 years old at a minimum. (Females first breed at no younger than 5 years of age, so her estimated minimum age is one year older than if she were a male.) She can boast having bred with four different partners on four different lakes, spanning two counties. The 25+ year-old Townline male, “Silver over Red, Orange over Green”, is unrivaled in terms of stick-to-itiveness, as he has held the Townline territory since at least 1994 — and still owns it. He has reared 16 chicks to fledging during his tenure, if we throw in the two from this year. Only two loons have raised more young: the current Oneida-West female (19 fledglings and counting on Oneida-East and Oneida-West) and the former Hancock male (17 fledglings from 1993 to 2009).

Although it is fun to gawk at the age and breeding success of certain star individuals, my quick analysis of the study’s oldest loons reinforces another point that I have made before — and one with substantial scientific importance: females are the ones that generally live to a ripe old age in loons. The reason(s) for this gender disparity are becoming clear. Males seem doomed to die young because of their participation in dangerous battles, and perhaps also their unfortunate proclivity for attacking fishing lures and baits. Inspection of the table above certainly makes one wonder whether males should rethink their high-risk approach to both territory acquisition and foraging. Then again, maybe there are compensating benefits that offset the costs.