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I will admit it: I am flabbergasted. When the Bass Lake pair hatched three chicks in the first week of July, I never gave them a chance. I suppose my pessimism was, in part, an attempt to protect myself from further disappointment. This year, as I have mentioned, has been a forgettable year in our study area. The dust has not yet settled completely, but 2019 will certainly go down as the worst year for chick productivity since I began the study in 1993. And we have had some dreadful breeding years!

The Bass Lake Miracle — hatching and rearing of three vigorous chicks on a tiny lake — is so far a welcome exception to the dreary pattern. As I noted in my previous post, however, the Bass Lake pair are fighting more than the negative tide of 2019. Lakes that you could throw a baseball across — well, lakes that Trevor Bauer could throw a baseball across — generally do not contain enough food to allow two chicks to reach fledging size, let alone three. Fawn Lake is a case in point. Slightly larger than Bass, Fawn hatched two chicks, which weighed 2.1 and 1.2 kilograms at capture ten days ago. So the smaller chick is just over half the weight of its sibling, and its survival prospects appear grim. Moreover, Evelyn reported that the beta chick was begging fruitlessly for feedings from the male today, while its fat and sassy sibling rested nearby. Such is the normal state of affairs for families that try to raise more than one chick on small lakes.

But don’t tell all of this to the over-sized Bass Lake family. As Linda’s recent photo shows, the trio of chicks there are beating the odds so far. During my visit to the lake today, the three-week-old chicks swam along in a tight group, tracking their foraging parents and getting fed constantly. The food items brought up by the parents were not tiny minnows and leeches, such as one often sees on smaller, food-stressed lakes, but crappies and yellow perch large enough that the chicks had to work a bit to swallow them. There was no desperate begging, no pecking of the small chick by its larger siblings. Most important, the size disparity among the chicks, quite evident a week ago, is less so now, which suggests that all chicks are receiving ample feedings.

I retain some healthy pessimism about the loon family on Bass. I have seen too many starved chicks on small lakes to feel otherwise. But if a pair of loons can adopt a mallard duckling, raise the duckling on fish they catch and feed to it, and teach it to dive as they do, I suppose anything is possible.

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We are feeling snakebit this year on the Loon Project. Late July in most years is a time of celebration — a time when we winnow the list of covered lakes to those with one or two chicks and stop visiting those that have failed to produce young. In most years, this narrowing process gives the entire team an emotional boost. Instead of surveying pairs that have lost two nesting attempts, have had a pair member evicted, or — worst of all — are sitting for the seventh week on a clutch of eggs that we know to be infertile, we focus on the positive.

Dropping failed pairs from our circuits gives us a pleasantly warped view of loon breeding success.  We smile while watching chicks ride on parents’ backs. We chuckle at the determined efforts of youngsters to dive like their parents, and at parents’ concerned peering underwater as they monitor those efforts. And we marvel at the rapid and well-choreographed diving responses of entire families to flying intruders, which no doubt succeed at hiding chicks from intruders and thus protect the territorial ownership of both pair members.

This year has been different. Owing to a late ice-out, a lengthy period of black fly abundance — and perhaps other factors we have not yet detected — 2019 has been a dismal year for loon breeding in northern Wisconsin. When I asked Elaina a few days ago to help assign each field observer to a circuit of lakes, this fact became undeniable. She scoffed. “We have just been to these lakes!”, she replied. She was right. Whereas an observer would normally visit each lake with chicks every three to four days, we are now visiting chick lakes about every other day. The reason is simple; only about a quarter of our lakes have produced young in 2019; last year, it was over half. I have begun to view the few pairs with chicks as the chosen ones.

The loon team is searching for a silver lining, but it is difficult. The list of failed lakes is a “Who’s Who” of traditional chick-producers. Blue Lake yielded only one chick in 2019 despite the efforts of two highly successful pairs. East and West Horsehead both failed to raise young. Neither pair on Two Sisters Lake reared a chick; one has to go back to 2010 to see the last time that happened. And on and on.

Elaina, back for her second year on the study, feels the blow harder than most. Last night, as we drove between our first and second capture lakes of the year, she and Tarryn grasped at a silver lining. “At least we will not have to carry the motorboat in at Buck and Greenbass”, they agreed. (The carry-in for canoes at both lakes is lengthy; to carry in a motorboat for capture, as we do most years, looks like masochism.)

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It is not all gallows humor and rueful comments this year. Linda Grenzer’s two striking photos show one of the few bright spots. In an apparent effort to compensate for the poor productivity of other lakes, the Bass Lake pair hatched not two, but three chicks! Two chicks is already a crowd for loon parents; Gabby Jukkala’s paper showed that male loons yodel three times as often while defending two-chick broods than with singleton chicks. Imagine the stress faced by the Bass Lake parents! But since Tarryn texted me excitedly almost two weeks ago to announce the spectacle, the parents have tended their over-sized family assiduously. Despite obvious size disparities between alpha, beta, and gamma chicks, all three are staying together and receiving regular feedings. Linda’s hilarious “loon pyramid” photo suggests that there are even brief moments of reluctant alloparenting.

I will be honest; I am on pins and needles. Bass Lake is a 40-acre lake. Only once in eighteen years of hatches — way back in 1995 — has the Bass Lake pair even fledged two chicks. Never has any pair in our study area raised three chicks to fledging age. (Washburn Lake did hatch three in 1997; they fledged only one.) So my scientist’s sense tells me that the gamma chick is doomed, and the beta chick’s survival is highly uncertain. But I am trying to stay upbeat about the family of five on Bass. I need something to cling to this year.

 

 

 

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The loon pair and mallard duckling remain a close-knit family, if a non-traditional one. This fact became clear on Linda’s recent visit to Long Lake, as the pair remained fiercely protective of their charge (as her photo shows), and the male permitted it to preen while standing on his back. But Linda’s observations also suggested that the duckling is not helping its foster parents’ in their efforts to safeguard their territory ownership.

Let me provide some context. During July and August, loons that do not have territories  look hard for them. Why? Well, because (with apologies to Jane Austen), “….it is a truth universally acknowledged that a single loon in good physical condition, must be in want of a territory.” Indeed, single loons search ceaselessly, and at times desperately, for territories and mates. They do not search blindly but instead heed a signal. The presence of chicks with a breeding loon pair is a shining beacon to unpaired loons that announces, “This is a good breeding territory; remember this lake, return to it next year, and claim it for your own!”

In order to counter the prying eyes and evil intentions of such nonbreeders, loon pairs play hide-and-seek with their chicks. This is not the kind of light-hearted hide-and-seek that we humans play with our offspring. Instead, loon pairs with chicks play a high‑stakes hide-and-seek game to keep nonbreeding loons from spotting their young.  And if pairs (or their young) play the game poorly, they place their future territory ownership at risk.

Hiding of loon chicks by parents often seems a difficult task. Loon chicks are chocolate brown in color and can hide near shore among rocks and logs — if they wish to do so. Nonbreeders, for their part, do not call ahead to warn of their visits. Instead, nonbreeders appear suddenly over a lake, flying at 70 miles an hour, and scan the lake’s surface for loon chicks. Often they land in the lake as well. Under these circumstances, it is a daunting task to keep chicks out of sight. Yet, if pairs with chicks are fortunate enough to spot flying intruders early and to be in a part of a lake from which their chicks can easily swim to shore, they sometimes hide their chicks successfully by means of an odd “dive and scatter” strategy.

Hiding of a fostered duckling from snooping intruders has turned out to be an even greater challenge, Linda reports. While keeping a fostered duckling well fed is easy, preventing intruders from spotting the duckling is comically difficult. Picture the scene from a few days ago. An intruder suddenly appeared overhead, emerging out of the early morning fog while the loon pair and duckling were resting. Both adults immediately dove and swam underwater towards the center of the lake to engage the intruder. Instead of diving itself and racing underwater to hide near shore, as a loon chick would have, the duckling freaked. When it spotted its foster parents far away and next to nonbreeders that had landed, the duckling raced towards middle of the lake, while peeping loudly, making itself very obvious. Needless to say, efforts by the loon parents to hide their youngster were at an end.

I know what you are thinking — the loon pair lost nothing from the conspicuous behavior of the duckling. The intruder might have been confused by the duckling’s presence, but it probably would not have confused the duckling with a loon chick, taken it as a sign of breeding success, and planned to challenge the pair for territory ownership next year. That is probably true, unless, of course, nonbreeders cue in not only on loon chicks themselves but also on protective and aggressive behavior exhibited by loon parents. Let’s hope the duckling’s misbehavior had no long-term impacts. It would be a shame if the loon pair suffered doubly — by rearing a youngster of the wrong species and losing their territory the following year.

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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.

 

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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.

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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.

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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.

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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.

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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.