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.

Two days ago we learned that the male on Hilts Lake and the female on the East Central territory on Nokomis Lake have become the latest angling casualties in our study area. The Hilts male swallowed a lure or bait and is dragging line from his bill; the Nokomis-East Central female has line wrapped around her left leg, which she now carried behind her. We are dismayed for the two loons involved, of course. The male on Hilts is among our tamest; since 2007, he and his mate have permitted us to approach them closely without alarm so that we can record an hour of their lives every week or so during the breeding season. Each of us looks forward to visits to Hilts because of the relaxed pair we encounter there. The Nokomis-East Central female too permits us to view her and her mate and young from close by. She contrasts markedly with her mate, who forces us to view from a distance of 50 meters or so to avoid getting an earful of alarm calls. When we spy a lone adult and chick from a distance on Nokomis-East Central, we keep fingers crossed that it is the docile, approachable female, not the male, who happens to be guarding and feeding the chick. (Good news: Seth reports that the Nokomis-EC female leg appeared to be dragging no fishing line yesterday, so perhaps she is out of danger.)

The list of loons ensnared in fishing tackle is longer each year. Observations and reports of this kind have become an unrelenting and disheartening drumbeat. In the early 2000s, close encounters between loons and fishing tackle were anomalies that I wondered about almost dispassionately. Each angling casualty brought sadness and frustration, of course, since one becomes attached to the loons. But such events were so uncommon that I shrugged the losses off as the inevitable consequence of habitat overlap between loons and humans. The steady increase in entanglements in recent years has sensitized me. These days I brace myself for the several – perhaps I should change that to “many” – that will occur during the season and wonder how we can assemble a team to rescue victims without compromising the behavioral and ecological goals of the research. In fact, I have begun to prod Project LoonWatch in hopes of encouraging them to put together a loon rescue squad – a group of 3-5 folks that can remain “on-call” during summers to assist birds injured by human activity.

And I have begun to worry about the loon population. Loons are clearly getting caught on fishing lines more often than before. This makes sense, as fishing activity continues to increase in northern Wisconsin. (It might also be the case that the proportion of inexperienced anglers – those likely to lose lures and fishing line in the water and not make efforts to retrieve and discard tackle that they lose – has increased.) Loons did not evolve in an environment with monofilament line, live bait and lures that mimic small aquatic creatures. Hence, they have developed no system for avoiding these hazards. If the number of loons swallowing and blundering into fishing tackle continues to increase, will so many adults die that the population cannot sustain itself?

A quirk of fishing entanglements makes the situation a bit more severe than it might first appear. As the cases of the Hilts male and Nokomis female illustrate, males and female loons are differentially affected by fishing. For reasons that we do not understand, males appear much more likely than females to ingest lures and baits, as the Hilts male did. We do not understand this difference, although one might speculate that males, having larger bodies to sustain, are less picky in chasing and consuming underwater creatures than are females. In any event, both sexes seem to be equally prone to getting monofilament wrapped around their wings or legs, but males are more threatened by lead-based tackle (sinkers and jigs) — which poisons them and kills them quickly – and by hooks that damage their throats and prevent them from opening their bills and feeding themselves. In short, males are more apt than females to fall victim to fishing tackle and in a way that is likely to kill them.

Why should we care if adult male loons are more vulnerable to anglers? Because, weirdly, males choose the nest site where eggs are to be laid and cleverly reuse nestsites where they have hatched eggs successfully in years past. So males are a reservoir of information about how breeding pairs can best use the nesting habitat within their territories to produce young. When an established, experienced male from a productive territory is replaced by new male (because of death or eviction), the new male does not know where to place the nest and must learn by trial and error. In constrast, when a female is replaced, efficient reproduction can continue uninterrupted, because the identity of the female has no impact on nest placement.

Thus, I grieve for the Hilts male not only because he is a sweet bird who permits us to watch him without complaint but because his demise will cause a new, ignorant male to settle, who must blunder from one failed nestsite to another before he discovers a good one that he will use year after year. And his years of inept breeding will subtract many offspring from the population.

image1Chris checked in on the Flannery-Velvet chick today. The chick, whom lake residents call “Houdini” because of his ability to escape certain death, continues to inhabit this odd world where it is necessary to hide under piers and avoid adults — rather than fraternize with two parents who feed him to satiation. When his mom is not bonding with a new male up on Flannery so that she can prepare herself for future breeding attempts, she spends time with him down on Velvet. Today Houdini begged from his mom repeatedly, but he also foraged for himself during a considerable period.

The photo above, generously supplied by Hugh Jones who lives on Velvet, is notable for two features. First, it shows a chick that is in full adult-like feather. That is, it has outgrown its chicklike, downy plumage and assumed adult attire. This fact, of course, is comforting, as it shows that the chick is getting the nutrients it requires to mature and prep itself for independence and migration to the wintering ground. Second, however, the chick continues its retiring ways. It has learned to avoid adults, because of the occasional beatings it had received from its stepdad. So it seeks protection, using whatever piers and pontoon boats will give it cover.

We have never witnessed a situation like this one. In all other cases, chicks that lost their fathers were either: 1) several weeks old and recipients of abundant feedings from their mothers, or 2) summarily ignored by their stepfathers and permitted to grow and mature without interference. Since we are in uncharted waters, we can only be cautiously optimistic. All we can say is that Houdini — whom LP personnel know attactionately as “white over white, pink over silver”, from his leg bands — continues to pass developmental milestones despite daunting obstacles.

We are riveted on the happenings on Flannery/Velvet Lakes. On these two lakes –united through a narrow channel so as to be a single waterbody — a tense scene is playing out with elements of a Shakespearean tragedy. A 13 year-old male, hatched on Townline Lake and a frequent intruder into various lakes in and just west of  Rhinelander, is opportunistically seeking to replace the deceased Flannery male. If he succeeds, he would shift from a territory on the Wisconsin River, where he has failed to fledge chicks despite three years’ of nesting attempts, and settle on a new lake that just this year produced chicks, breaking its own eight-year skein of nesting futility. In other words, this would be a step up for the male.

This male’s effort to relocate to a more productive breeding site has taken a dark turn. While visiting Flannery and bonding with the widowed female there, the male encountered her young chicks. One of those chicks the male killed weeks ago by pecking it to death when it was quite small. The surviving chick too has suffered repeated beatings by the male to the point where the chick now spends much of the day hiding underneath piers on Velvet Lake to avoid the abuse. This grisly spectacle has had severe consequences, as the chick is only about 60% of expected body mass for its age. Clearly the physical beatings the chick has suffered, the presence of only one parent, and the inability of the female to feed her surviving offspring to satiation while defending him from intruders threaten his survival. It remains highly uncertain whether the chick will reach adulthood.

I had expected that the dreadful treatment of the Flannery/Velvet chick by an intruding male would make me feel a gut-level hatred of the intruder. Indeed, I was horrified by the fiasco unfolding there. But knowing that the male wreaking this havoc is an old friend of ours — one that I watched as a chick on Townline Lake back in 2002, a young floater on Langley, Julia and Hanson lakes, and finally a failed breeder on Wisconsin River — has complicated my perspective. I am rooting strongly for the chick to survive the vicious onslaught, start to forage for itself, and fledge. But I am also cheering a young male loon who is trying to turn his life around by moving into a new territory that offers the promise of abundant fatherhood.

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The Loon Project counts on efficient exchange of information with lake residents and loon enthusiasts as a means to acquire good scientific data. We cover enough lakes — about 120 this year — so that we make visits to them only once every 5 to 7 days. This permits us to track the identity of the breeding pair and record their breeding activity. Over time, we accumulate important data on territorial fidelity, eviction of breeders, and their relocation to other study lakes. But weekly hourlong visits leave lots of holes in our knowledge. So it is helpful that almost all of our lakes are occupied by humans who take an interest in “their loons” and contact us or the Wisconsin Department of Natural Resources when something is amiss.

Yesterday, a resident on Flannery Lake called with distressing news. The male on the lake, a 14 year-old reared on Washburn Lake, was dead and being fed upon by a mink. We were particularly saddened to hear such a report from Flannery, because the breeding pair had attempted to rear young every year there since we began to follow them in 1993, but had not fledged a chick successfully since 2006. That unlucky string seemed about to be broken when, earlier this month, the pair hatched two vigorous chicks. We were delighted, though perhaps less so than lake residents, who had watched their loon pair build nests, lay eggs, and incubate them diligently year after year only to lose them — or their small chicks — for reasons unknown.

This morning Seth visited the lake to see whether the female and chicks were still alive and whether another male had taken the deceased male’s place. He snapped the photo above, showing that the female, who is at least a quarter of a century old, is alive and well, as are both chicks. However, he also reported that a possible incipient pair was present on the lake. This makes sense. As I have noted in recent posts, male loons use their yodels to keep hopeful settlers at bay. With no male present to yodel, intruders flying overhead readily land in the lake. Since the female cannot safely leave the two-week-old chicks alone, she cannot easily engage intruders and drive them off. In short, Flannery is prone to intrusion and settlement.

Despite the difficulty of her situation, Seth reports that the Flannery female continued to show territorial behavior towards intruders this morning. It remains to be seen whether she can find refuge on the lake such that she can both avoid any new pair that settles and forage to sustain herself and her young chicks. It is a tall order. Indeed, we have only once observed a female whose mate died or was evicted raise a young chick on her own. In 2012, the male on Squash Lake died of lead poisoning owing to an ingested sinker, leaving his mate and a chick only a few days old. The Squash female that summer miraculously succeeded both in rearing the chick to fledging and in pairing with a new male — a lesson to us all that child-rearing need not prevent an active social life. “Miracle Chick”, as we came to call the survivor on Squash, became our most revered juvenile that year. (Miracle Chick is pictured below with Kristin and Gabby.) Lauren's capture video and stills 082

So there is reason for hope for the young Flannery chicks. If she is vigilant and fortunate, a female can raise a chick, perhaps even two, without help from a male. Considering the long odds of such an achievement, we should certainly resist optimism at this point. We will keep an eye on this fractured family, and I will let you know how things turn out.

We were horrified last spring, when one of our best-known territorial males — and a super tame bird to boot — became hopelessly entangled in fishing line. This male, the long-term resident on Jersey City Flowage (“JCF”) had swallowed two lead sinkers, and monofilament line was wrapped tightly about his bill, making it impossible for him to eat. In short, the JCF male was destined to perish quickly from lead poisoning and/or lack of food. However, the folks from REGI freed him and used new technology to pluck both lead sinkers from his gut. Although he lost much of his tongue because of the fishing line, we were heartened when Linda found him in July of last year gorging himself on bullheads near his old territory (see photo below). LMG_1395 Jersey Male n Bullhead

But recovery after a brush with death was just the beginning for this bird. In order to reclaim his previous position, the male needed to regain his strength, migrate successfully to his winter quarters, survive the winter, migrate back north, and then — most challenging of all — regain possession of his former territory, which had been quickly snapped up by another male after the injury. (The new male bred successfully last year and was banded by our team.) Yesterday, Linda confirmed that the old, war-torn JCF male has negotiated all of these hurdles and settled in a breeding pair back on his old territory (see Linda’s photo below). We presume that he is also with his old mate, but she is one of the few wily adults that has managed to elude us, despite several efforts at capture. So she is still unbanded. LMG_3377 JCF Male The resilience of the JCF male is important. He is only the third adult to have been severely injured by fishing tackle, lost his territory, and recovered to reclaim it. Three data points can never be a robust sample, but we also have many cases where entanglement occurred and adult loons did not recover. In fact, we have about 9 well-documented cases of death following entanglement, which, combined with the three success stories, yields an estimate of 25% likelihood of recovery. So while the story of the JCF male’s journey from disaster to full recovery lifts our spirits, it is hard to forget that this is the exception, not the rule.

A lot can happen in a short time, it seems. I have spent only three days in the study area so far, but already we — Joel, Eric Andrews and I, and our incredible citizen scientists Linda Grenzer and Al Schwoegler — have found 8 active nests. Considering the territories we have visited recently and those we have not, I estimate that about 15-20% of all pairs in the study area are already incubating. Clearly the pairs have shortened the window between ice-out and egg-laying in order to compensate for the very late spring this year. I suspect this is possible, in part, because females were able to recoup much of the energy consumed during spring migration by foraging for weeks along rivers in the study area, before their breeding lakes opened up. That is, the extra foraging time near their territorial home apparently compensated for the foraging time that would normally occur on their territory.

Territorial turnovers have been common this spring; many marked pair members from 2013 either failed to return in the spring or did return but were evicted from their territories. The evicted birds include a young “ABJ” (“adult banded as a juvenile”; meaning a loon we banded as a chick) male from Schlect Lake. This ABJ male, hatched on Fox Lake in 2005, produced two chicks, of which one fledged, in 2012. But in early 2013, the Fox ABJ had been replaced by another ABJ male, this one also hatched in 2005, but on McNutt Lake. In late 2013, the Fox ABJ was able to retake his territory (possibly after the McNutt ABJ left it) and lived there the rest of the summer. However, two days ago, Eric and I witnessed a nasty battle between the Fox and McNutt ABJs (now both 9 years old) that culminated in the exhausted and defeated Fox male taking refuge on shore to avoid further attack from the McNutt male. Quite a grim spectacle! It remains to be seen whether the Fox ABJ can recover, drag himself off of this tiny 25-acre lake and get on with his life.

While our problems pale in comparison to the desperate life-and-death struggle that the Fox ABJ is facing, this latest contest is troubling to us as well. You see, we have hypothesized that dangerous contests of this kind likely occur when very old males (with very little reproductive fitness to lose) roll the dice by battling to win a few more years on their territory rather than accepting displacement by a younger, stronger male. (This is termed the “terminal investment hypothesis”.) Naturally, we must use statistical tests on a large body of data before drawing any conclusions. Still, it was unsettling to see a vigorous young male — and one that doubtless would have many potential future years of reproduction ahead of him — suffer a life-threatening encounter that flies in the face of our pet hypothesis.

It has been awhile since my last post. Sorry about that. With our study animals hunkered down in the Atlantic — mostly off of Florida — there has not been much to write about. But they are molting now, beginning to vocalize, and are readying themselves for a return to Wisconsin. Although the northern weather is not cooperating at the moment, our study animals will soon begin winging their way north.

Even after the summer, though, we accumulate data on our birds. How? By receiving reports of recoveries of our loons during migration and on the wintering grounds. Now, a “recovery” is, in essence, an unpleasant event. The term refers to a report of a bird banded with a U.S Fish & Wildlife Service metal band that has died, been found, and been reported to the Bird Banding Lab in Patuxent, Maryland. I get an e-mail from the BBL each time someone recovers one of the loons we banded. When I see the BBL address pop up on my phone, my pulse races, as I fear that one of our valuable breeding birds may have died. Each time we lose a loon that we have known and studied for 15 years or so, I grieve a bit. This happened two years ago when I learned that the long-time breeding male from Hancock Lake had died. More often than not the news from the BBL is sad but not devastating, as most of the recoveries are of first-year loons — birds we banded as chicks the previous summer that did not survive their first fall migration or winter. We are always sad to lose a bird we banded, but we understand that its first months of life pose a severe test for a loon, as it must complete migration, learn to forage in the ocean, and face a set of dangers to which it is unaccustomed.

Something positive emerges from recoveries. As we accumulate a record of which first-year loons have died and which have survived, we have a chance to confirm a pattern that we detected recently from our summer work. Young hatched on small, acidic lakes return to the breeding grounds at a lower rate than those hatched on large lakes of neutral pH. We do not yet know at what point this difference in mortality occurs. Do juveniles from small, acidic lakes fail to make it off of the breeding grounds? Do they die disproportionately during fall migration? Or do they tend to die in larger numbers after reaching the wintering grounds? Recoveries of these young birds during late summer, fall migration, and winter — as sad as they are — can provide us with the valuable answer.

One of the many triumphs of the 2013 research season was the capture and banding of the male from Mildred Lake. Although unmarked, the Mildred male was unique behaviorally. Since he took over in 2009, he was an aggressive presence in his territory. While most males get lackadaisical — or perhaps fearful — about approaching and engaging intruders, the Mildred male always did so without hesitation. He was a big, intimidating bird. Once, in 2009, he even took to the air to express himself; I will never forget him giving a ringing rendition of the territorial yodel while chasing 9 intruders in the sky far above my canoe. (This is the only time that I have ever witnessed a loon yodeling in flight.) In 2013, when, after years of fruitless incubation, he and his mate finally hatched chicks, they both tirelessly defended and fed their young until they were full grown. So he had just had a big year.

Alas, while foraging nearby on Crescent Lake, the Mildred male ran afoul of an angler.  On 17 October, the male was found there with a swallowed hook and bait inside him, still attached to a long fishing line and the fishing rod. Apparently someone left their bait and rod unattended, and the male swallowed the bait and could not free himself. As my posts from earlier this year have shown, we have a decent chance of saving a bird — even one that has swallowed a hook — if we learn about the incident quickly and can capture it soon after the event. So it is a real shame that no one was present or had the courage to report this incident and allow us to help the bird.

Our only consolation is that the Mildred male left two big strapping chicks behind, both of which are fending for themselves and not impacted by his demise. We know from genetic tests that one of these chicks is a male and the other is a female. Perhaps we will see one or both of these offspring back in three or four years’ time. That might take some of the sting out of the horrible loss of their father.