You might think that the month-old Long Lake duckling would have been satisfied with its lot. Facing certain death after it became separated from its mother and siblings four weeks ago, this youngster somehow crossed paths with a loon pair that was grieving for its own lost chick. Though they look somewhat alike on the water, loons and mallards are not closely related among birds. Loons’ closest relatives are penguins and pelicans; ducks’ are chickens and grouse. But dire need trumped phylogeny, in this case, and the loon pair and duckling became a family. The loons are attentive parents, as Linda Grenzer’s photo shows.

The difference in diet between loons and mallards proved no obstacle; the duckling greedily consumed fish captured and offered to it by its adopted parents. As I mentioned in an earlier post, Elaina and Linda also found that the duckling foraged on its own, taking invertebrates and possibly also plant material from the shore and passing vegetation, as a normal mallard duckling would.

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Recently, though, the duckling has shown itself to be a far more versatile forager than any normal mallard. You see, it also dives. Linda verified this behavior with numerous video recordings. The duckling, moreover, does not dive for an instant and then pop immediately back up to the surface. It submerges itself for several seconds, reaching the bottom of the lake — which is more than a meter away — and returns to the surface. (Linda’s photo captured one of these plunges, just as the duckling’s tail was about to disappear beneath the water.) We know that the duckling dives deeply, because it sometimes grabs a prey item from the bottom, brings it up to the surface, and consumes the item next to its foster parents. While Linda watched, for example, the duckling captured and ate a snail.

To appreciate the shock I felt upon learning of the novel diving behavior of this mallard, one needs to understand a bit of duck taxonomy. Mallards are “dabbling ducks”, so named because their aquatic foraging consists of upending themselves — dunking their heads in the water and sticking their tails straight up in the air — while picking up small animal prey and plant matter from shorelines. They never become fully submerged, like loons do. As dabblers, mallards are allied with gadwall and teal, which feed similarly, and differ starkly from other group of ducks, like scaup and bufflehead, which are “diving ducks”. So by mimicking the diving behavior shown by its foster parents, this little duckling is thumbing his bill at a well-known scheme of avian taxonomy.

I would give a lot to get inside the duckling’s head and learn how and why it began to dive. Was it pure learning picked up from the loon pair, which dive constantly and might have served as role models? Or did the youngster attempt to dabble, find itself in water too deep for dabbling, and simply “extend” its dabbling efforts to reach the lake bottom, where food awaited? Either way, the duckling has shown incredible flexibility in acquiring food.

I never wanted to fall in love with this duckling. I thought that Daffy and Donald had ruined ducks for me forever. But this little guy’s plucky adaptability might just turn me around.

 

At first glance, a mallard duckling raised by loons would seem to be in a pickle. When your parents dive and you do not, you spend many anxious moments waiting on the surface. Furthermore, when you instinctively prefer to spend time in the shallows, and your folks prefer open water, you must tolerate their habitat preference as best you can, while nervously peering under water a bit more than usual.

These minor sources of stress seem tolerable for the Long Lake loon-duckling. As it turns out, there are benefits to having two parents assiduously stuffing food into you instead of one parent merely leading you to foraging areas.

You see, when we first observed that a loon pair had adopted a duckling, we were unsure how the duckling might be getting food. We could see that the duckling was healthy and strong — that it continued to grow and thrive. How, we wondered, was a dabbling duck that evolved to pluck and consume small, squishy invertebrates from the shallows surviving with two parents determined to feed it long, rigid, scaly items captured from the deep?

As we can see from Elaina’s stunning photos, the duckling’s solution has been to accept the proffered scaly items — though only small ones that do not pose a swallowing hazard — and to supplement this steady vertebrate diet with bits of animal and plant material gathered on the fly. To look at the bird, this duel feeding mode provides a favorable balance. The adoptee has matured rapidly from a tiny fuzzball into a strapping individual fast approaching adult (duck) size.

While it is physically healthy, the duckling’s mental state is less clear. This bird is a living, breathing test of nature vs. nurture. If the duckling behaves as genes dictate, it will soon join others of its species in huge foraging groups that congregate on lakes at this time of year. But it is thoroughly imprinted on its loon parents, not on mallards. If it has lived too long as a loon chick, it might attempt to associate with that species. Even in this worst case scenario, all is not lost, I think. Full grown mallards, even those that evince inappropriate affection for loons, know that they must bolt when a loon comes stalking them.

“Wow, loon chicks and ducklings sure look alike!” Evelyn remarked upon returning from Long Lake two weeks ago. Elaina, a veteran assistant who has seen a lot of both, thought this statement a bit odd, but was not terribly surprised. The chicks of loons do look somewhat like ducklings. Both are duck-shaped and downy, quite unlike adults of their respective species. And after all, Evelyn had never laid eyes on a loon chick before.

Ten days passed, and it was Elaina‘s turn to visit Long Lake. She was stunned to find the female slowly swimming about with a young mallard duckling on its back, and she took these cool photos to document her observations. The female, Elaina noted, acted as loon parents always do: she nervously guarded her small passenger, scanning the skies for bald eagles and peering underneath the water at intervals for large snapping turtles and muskies. The nearby male too behaved normally. Like his mate, he was vigilant, but he also caught tiny fish, carried them to the duckling on his mate’s back, and attempted to feed it, just as he had his own chick last year. His efforts were in vain; the duckling refused all food.

Many questions leap to mind here. First, how on earth did a loon pair meet up with a single mallard duckling? Second, why on earth would they adopt the duckling rather than raising their own chick or chicks? Third, why does the duckling participate in this charade? Fourth, will loons, which provide their chicks with a large fraction of their food, be able to rear a mallard duckling, which normally finds all of its own (very different) food?

The first question is the easiest. Loons and mallards are both common on our study lakes. They encounter each other all the time. But the usual result of such encounters is starkly different from what Evelyn and Elaina observed. For their part, mallard ducklings swim about with their many siblings in a large, tight, comical flotilla behind their mother. Loons often stalk these flotillas, causing the mallard female to rush her offspring to the nearest shoreline. Loons occasionally attack and kill ducklings, but do not eat them (to our knowledge). The usual nature of loon and mallard interactions, in other words, is a far cry from what Evelyn and Elaina observed.

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The second question — what the loons are doing adopting a duckling – is the most vexing. Yet we have insights that permit us to reconstruct some parts of the story. The shape, size, and number of eggshell fragments in a loon nest tells us the fate of a nesting attempt. When I visited Long on 13 May, the pair had just started nesting, so we expected a hatch on 10 or 11 June. Indeed, Evelyn noted many small fragments on Long on June 14th—- a clear sign of a successful hatch. So we know that the Long pair did hatch an egg —- a loon egg — about two weeks ago. Loon pairs provide extensive parental care for their young, of course, and are hormonally primed to do so. Without question, then, the Long pair had high levels of prolactin in their blood in mid-June, as they began to care for their own chick. The rest of what occurred to bring about this most unlikely association is open to speculation. Perhaps a tiny duckling, the last to hatch in its brood, was left behind by its mother and siblings. Maybe the duckling became separated from its mother and siblings following an eagle attack. In any event, the tiny waif was likely discovered by the loon pair just after they had lost their chick and were predisposed to find and care for anything that even remotely resembled a newly-hatched loon.

Classical studies of animal behavior help us answer the question of how the duckling would accept loons as its parents. Ducks (like chickens and many other precocial birds) have a well-known capacity to imprint on the first large, moving, animal-like object they encounter after hatching. This instinct makes sense, because that object is almost always their mother or father. Imprinting helps them fixate and remain near their protector at all times. But a duckling hatching after its sibs had left would not have had a chance to imprint on any object. So it is conceivable that such a duckling might see and latch onto a loon pair. If ducklings accept humans as parents, they should easily accept loons.

Can a loon pair provide enough nourishment and feeding opportunities to allow a duckling to survive to fledging? We shall see. Loons have adopted ducklings before. A published study from the late 70s reported adoption of five eider ducklings by a pair of Arctic loons, and I reported a few years back on a pair of common loons in British Columbia that adopted a common goldeneye duckling. In both cases, the ducklings were known to have survived for many weeks in the care of their foster parents. But a mallard is a dabbling duck, not a diving duck, like an eider and a goldeneye. Mallard ducklings normally feed themselves on a variety of invertebrates and plant matter found on shorelines and in shallow water — not fishes provided by a parent bird. Despite the seeming disconnect between loons and mallards in diet and mode of feeding, Elaina’s photos show an alert, healthy-looking young mallard. Since we know the loons have been parenting the duckling for at least ten days, we must conclude that the youngster is receiving substantial nourishment by some means. So perhaps loons can keep a mallard duckling alive.

In short, we know bits and pieces of the story of how a pair of loons came to care for a mallard duckling. Much regarding this series of unlikely events remains shrouded in mystery. Even in our considerable ignorance, though, it is impossible not to marvel at this charming spectacle.

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.

For the past several years, I have begun to turn my attention to the effect of lake size on breeding success of common loons. Clearly loons on large lakes produce more and healthier chicks than those on small lakes. We showed that on our paper from six years ago. This raises the question of why loons ever attempt to breed on small lakes. They are doomed to failure — or at least to greatly reduced likelihood of success. The water is muddied further by the fact that loons reared on small lakes prefer to breed on small lakes themselves. That’s right: chicks fortunate enough to avoid starvation on small, food-limited lakes replay the whole scenario as adults, subjecting their young to the same travail they themselves faced.

The puzzle of loons breeding on small lakes was thrown into start relief again yesterday, when I visited the Wind Pudding-West territory on a scouting trip for nocturnal capture. After not finding the chick and parents in the shallow bay on the lake’s western side, where we had seen them on previous visits, I headed towards the channel that connects that bay with the main lake. I was crestfallen when I reached the channel, as it was choked with lily pads and grasses to the point where it was difficult for me to find a passage through — even in a canoe. This discovery led me to doubt whether the pair might lead their chick through the channel and into the main lake as a means of finding more food for it. I began to fear that — walled off from an abundant source of food — the chick had probably starved to death on the shallow western bay since our last visit.

I had underestimated the determination of the pair to provide for their chick. As I paddled to the end of the navigable portion of the channel, I heard a chick’s desperate cries to its parents. I spotted the chick about half way across the marshy isthmus that now separates the shallow western bay from the main lake. The isthmus is no more than 20 meters wide perhaps, but it is densely overgrown with marsh grass to the point where the chick — equipped only with legs at the very posterior of its body — was forced to lunge awkwardly forward in order to make headway towards the main lake. To make matters worse, the chick had no clear idea of where it was going. I caught the chick’s initial confusion on video, as it sits within the marsh grass, uncertain how to extricate itself.

The second installment shows the chick after it has blundered around in the grass for a time but finally gotten a sense of where its parent wants it to go. The chick stops to give a distress call, then hears its parent call to it, which seems to give the chick the strength to complete its journey. (Apologies for the nervous narration and grainy video!)

The fact that the parents can entice this year’s chick to cross the isthmus and take advantage of food in both the western bay and main lake means that they are better off than they were here in 2016, when a chick wasted away and finally died of starvation. However, we caught the chick and female in the video last night. They are both severely underweight. The female, in fact, has the lowest mass we have ever measured for an adult loon. So even if the pair can find enough food to fledge the chick, chick-rearing seems to have taken a toll on the parents. Add yet one more item to the growing list of reasons to avoid breeding on small lakes with limited food.

I must confess that I had mixed feelings to learn this week from Nelson that the North Nokomis pair had hatched two chicks. Despite having seen scores of newly hatched chicks, I still enjoy watching the tiny fuzzballs bob up and down next to their huge parents while the adults, in turn, move gingerly around their tiny young to avoid injuring or drowning them.

So it was, in one respect, nice to learn that the North Nokomis pair had hatched the eggs from the conspicuous nest I had inspected on 25 July, after following the simple, clear instructions from my research team. But I recall thinking, “Oh geez!” on that date, because only two other breeding pairs of the 120 that we follow were still sitting on eggs. (Both of those, we had determined, were cases of infertile eggs that the pair had incubated for six weeks or more.) I have always presumed that chicks hatching in late July or August have too little time to mature physically, develop foraging skills, and learn to fly in time to make the fall migration.

Now we have the data to look at this question robustly. In other words, having captured and marked 983 chicks since 1991, we can determine whether hatching date is a predictor of survival to adulthood. Logically, there must come a date in late summer beyond which chicks run out of time. However, pairs might face a gradual decline in the likelihood of their chicks surviving migration, or there might be a rather sudden threshold date past which chicks that hatch cannot survive.

If we look at all chicks banded from 1991 on, and calculate how many have made it back to the study area as adults, we learn what the figure

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shows. In short, hatching date does not appear to influence survival to adulthood strongly. At the very least, we can say that chicks hatching in mid-July survive at a rate no lower than those that hatch a month earlier. There is a hint of a decrease in survival from early to late hatches, but it is only a hint.

As usual, our data are not perfect. In fact, we have too few cases of very late hatches to gauge the likelihood of the two North Nokomis fuzzballs (which hatched on about 28 July) making it off the lake this November. On the plus side, 470-acre North Nokomis Lake has one of the highest rates of survival to adulthood in the study area. (The territorial males on Gilmore and Cunard were hatched there.) I would like to think that the gutsy North Nokomis pair will be rewarded this fall with two healthy fledglings. So I am keeping fingers crossed for them.

It is July and time to hide the chicks! That’s right; while human parents show off their progeny — perhaps partly to solicit help in caring for them — loons do the opposite. You see, intruders looking to evict territorial residents scour lakes for chicks, because the presence of chicks indicates that the lake contains good nesting habitat and abundant food. So by producing young, a breeding pair has put a giant target on their backs, providing an incentive for any intruder that discovers the chicks (like one of the six intruders shown in Linda’s photo) to return the following year and make an eviction attempt. We should expect, therefore, that parents would hide their chicks from intruders whenever possible.

Of course, breeding pairs are fighting a losing battle. On the one hand, they must feed and protect their chicks, which includes vocalizing often to warn their mate and chicks of passing eagles and other dangers. On the other hand, when intruders fly over or land, parents need to ignore the chicks altogether. Toggling between these two behavioral modes is no small task. Furthermore, while it is desirable to protect your long-term ownership of the territory by hiding your chicks from intruders, you do not want to lose them in the process!

Although chick-hiding is a tricky business, loon families do have a strategy for coping with the sudden appearance of intruders overhead, which fly over at a speed of about 70 miles per hour. We call it “dive and scatter”. At the appearance of a flying intruder in the distance, a loon pair and their chicks quickly slip under water. The chicks swim toward shore and, once there, are hidden by their brown plumage, which makes them resemble rocks or logs. Meanwhile parents swim under water to the middle of the lake, which draws the intruders to them and not the chicks. The aim of this coordinated behavior pattern by chicks and their parents seems clear: keep intruders from seeing the chicks. On its face, dive and scatter behavior clearly seems a means of helping parents’ maintain possession of their territory.

I need to pause here for a second to consider an alternative explanation for dive and scatter. In fact, the most obvious reason why a pair and chicks would dive and scatter is to protect the chicks themselves. Intruders do kill chicks commonly, so this is a viable hypothesis at first blush. But chicks are most vulnerable to being killed by intruders in their first two weeks, so dive and scatter as chick defense — if it is a viable explanation — should occur mainly among small chicks. Yet dive and scatter occurs rarely in small chicks and very commonly in those four weeks and older. So the hypothesis that dive and scatter is a behavior to protect small chicks from intruder attacks can be easily rejected by its timing.

We have known about dive and scatter behavior for some years, but yesterday on Woodcock Lake I learned that loon parents know when to call off the ruse. While feeding their single chick along the lake shore, the Woodcock pair spotted two intruders in flight. The family dove and scattered, the chick hiding near shore and parents making for the lake’s center, in stereotyped fashion. Following the script, the two intruders landed by the parents (and far from the chick), the four adults circling and diving together for several minutes. The charade abruptly fell apart when an eagle flew over the part of the lake where the chick was hiding. Both parents immediately ceased interacting with the intruders, wheeled towards the eagle, and wailed desperately for several minutes, while swimming in that direction. In a half-second, the breeding pair had morphed from cool, detached individuals with nothing to hide into into frantic worry-warts!

Some might view such a loss of composure by a breeding pair to be quite costly. If intruders are able to learn about the presence of chicks by detecting chick defense behavior such as that shown by the Woodcock pair, then the pair exposed themselves to the threat of future eviction by wailing to defend their chick in the presence of two intruders. A clear blunder….until you consider that the alternative was to lose the priceless product of their summer’s breeding efforts.

 

Though it sounds odd to say, people put loons on a pedestal. Their love for loons causes many people to want them to be a bit better than us. Of course, this is the origin of the popular myth that loons mate for life. Such a handsome animal, it seems, should have behavior to match. Besides, loons certainly appear to work so well together in foraging, defending their territory, and rearing young that one can easily imagine that male and female are committed to each other deeply.

Having studied several other species of animals before turning to loons, I did not share the expectation that loons would be good role models for humans. I had seen too many cases of nature red in tooth and claw. In fact, I suppose I expected to learn ways in which loons might not fit the mold of traditional monogamy. What has surprised me the most of all my findings is the degree to which loons have broken that mold. Rather than aiming to remain paired with a single mate throughout their lives, loons seem pursue a far different but straightforward goal. They seek to produce as many chicks as possible by remaining on a breeding territory whenever possible. This strategy requires them to turn a blind eye when their mate is evicted by another loon. Their allegiance is to the breeding territory, not the mate.

No territory illustrates the cold pragmatism of loons better than Blue Lake-Southeast. Recent years have been turbulent on Blue-Southeast. In 2015, the male was evicted by an unmarked male after producing two chicks with his mate. The displaced male hung around on the lake and later regained his position, but last year was a repeat performance; this time a four-year-old male from Bolger Lake evicted the long-term male after hatching and killed the single chick. In a scene worthy of Greek mythology, the Bolger bird actually picked up the lifeless two-week-old chick while chasing its mother across the water’s surface.

Now, if a human mother had witnessed such a grisly spectacle, I doubt if she would have been able to forgive and forget. But loons are not humans; the female whose chick had been killed by the usurper quickly paired with him and remained so this spring. The unlikely pair weathered the black fly emergence in May, hatched a chick in early June, and are now raising that chick on the east lobe of Blue Lake. As the triptych of photos above shows, I caught up with this very tame family yesterday afternoon. At the time, “Chick-Killer” (as my field team affectionately calls the male) was enthusiastically diving for food for the thriving chick, while the female looked on. The dutiful, coordinated parenting of the two adults suggested that they constitute an indivisible unit — that their pair bond would withstand the test of time. But looks are deceiving.

A few years ago, my daughter and I were talking about her high school homework. I cannot recall precisely what class we were discussing, but a moment occurred when I became concerned that she was unprepared for an upcoming test. Anxiety hung in the air for a second before she reassured me. “Dad”, she said with a twinge of impatience, “I am a nerd”. It was her way of telling me that she was studious, exacting, and did not need to be told to get her work done.

As you all know by now, I too am a nerd. I wear that label — like my daughter does — as a badge of honor. The nerds I know are thoughtful, bookish folks who enjoy making fine distinctions and extracting subtle patterns from scientific data. Nerdiness of this kind is essential to a scientist, of course. Publishing our work and being taken seriously by our colleagues requires that we navigate a mine field of biased samples, uncontrolled variables, and specious correlations to arrive at valid conclusions to our questions.

Nerds are different. Most people, while chatting with a stranger in a supermarket line, can get away with saying, “Aaron Rodgers killed the Packers last year with his erratic passing in big games”. A nerd, however, would want to look at the data. S/he would examine Rodger’s passing statistics against teams with winning records and division rivals to see if, truly, he played worse in those games than in less important contests. While nerds can be annoying nit-pickers in society — the kind of people you want to avoid sitting next to at a party — we are quite valuable as scientists. We have the patience and passion to discover true causes of patterns in nature.

I was able to bring this patience to bear on a recent question about loon behavior. In my ongoing investigation of senescence in male loons, I faced a puzzle. The territorial yodel of males serves two purposes. It is, most obviously, a territorial call that males emit when a competitor is flying overhead or sitting nearby in the water. At such times, the yodel announces the willingness of a male to fight for territory ownership. But the yodel also serves to protect the young (see Linda’s photo, above); that is, male parents often yodel to prevent landings of flying intruders, which sometimes attack and kill chicks. Why does it matter that the yodel serves two purposes? Because I am trying to make a nerdy distinction: Do old male loons yodel more than young males because they are defending their territories, or do old-timers yodel more simply to defend their chicks?

This distinction is important. If you have been following this blog, you know that old male loons make a terminal investment in reproduction. The most obvious evidence of terminal investment by old males is their tendency to yodel more often than young males. But since yodels occur both in territory defense and in chick defense, it was not immediately obvious whether old males were yodeling their heads off at intruders simply to protect their chicks or to maintain ownership of their territories. Fortunately, we have enough yodel data from periods with and without chicks to see if the increased yodeling of old males occurs at both times. It does! Hence it seems that old males are employing the yodel call to defend their territories as well as to defend their offspring.

To a nerd, the ramifications of this finding are profound. An old male who yodels simply to protect his chicks is investing extra energy to rear his offspring to adulthood at the possible expense of his own survival. This is rather a short-term strategy, as it is aimed at rearing young to 11 weeks of age, after which young are out of the woods, and the investment has been successful. An old male without chicks that yodels, however, is taking a long-term view. Chickless males are months away from producing young. Their yodeling is aimed at guaranteeing territory ownership for many future months, even years. Although terminal investment in offspring is rare in animals, terminal investment in territory ownership is virtually unknown. So the stepped-up yodeling by old, chickless male loons is an exciting finding. As you might imagine, this result has set off quite a nerd celebration!