fishing

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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.

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It is human to overgeneralize based on the chance co-occurrence of rare events.  As a scientist, I know this. I spend a good deal of my research time sorting through quantitative patterns in data, fending off the tendency to infer a meaningful biological pattern where only chance trends are present.

And yet, the events at Alva Lake last night shocked me. The Toussaints, dear friends who live on the lake and kept me alive during my first year of loon research in 1993, had informed me before my team attempted capture of the breeding pair and their month-old chick that the male had been holding his leg strangely, as if injured. My crew had reported no abnormal behavior of the pair; indeed, I had seen only normal territorial and parental behavior when I had scouted the lake for capture at noon. Still, the Toussaints are careful observers of loons, so their statement gave me concern. I told them as we cast off from the dock that we would try harder than usual to catch the male, just in case.

Capture was swift and uneventful. Both pair members sat protectively on the lake’s surface as we approached slowly and scooped them into our net. After catching the chick as well, we headed back to the dock feeling good about ourselves. Not until we inspected the female’s legs on shore did we detect anything amiss. As the photo shows, the female’s left leg was encircled tightly just above the foot by Dacron fishing line (used commonly in Wisconsin for muskie fishing), and a 5cm-long thick snarl dragged behind. The line had become tight enough to bite into the leg and cause a painful wound. Taking great care not to worsen the wound, we cut through the super-strong line and removed it. Fortunately, the entanglement appears to be recent, the wound superficial. The female should recover fully within a week.

Surrounded by three generations of Toussaints and still jittery from seeing the female’s leg, we were ill-prepared for the sight of another, more severe injury on the male. In this case, monofilament line had become wrapped around the leg just below the ankle joint. Again the line was constricted tightly around the leg, but this entanglement had occurred many months ago and the skin and keratinized scales of the loon’s legs had overgrown and surrounded the monofilament strands, leaving the circle of line protruding to the outside via two holes in the skin, like an earring. Though absorbed and surrounded by leg tissue, the line had caused local inflammation, as revealed by the irregular swelling in the adjacent portion of the leg. After an emergency consult with Mark Naniot of Wild Instincts, we resolved to pull out the line if we could do so without doing further harm to the bird. Fortunately, once cut, the line slid easily out of the holes, revealing infection but an injury from which the bird should recover.

Shaken as I am by seeing back to back angling-related wounds, I chalk up the discovery of two such similar injuries within a mated pair mostly to chance. That is, there is no reason to suppose a sudden, devastating impact of fishing line on the health of common loons. After all, we have captured dozens of other loons this summer that showed no ill effects from having lived in waters plied constantly by all manner of fishing lines, lures, baits, bobbers, and sinkers and riddled with tangles of line left behind by grouchy anglers. All but a few loons we have seen have thrived for many years in Wisconsin waters, despite this piscatory onslaught.

So what can we learn from the events of last night on Alva Lake? Two lessons, I think. First, loons are tough. Designed for maximum strength and minimum thickness, fishing lines bite deeply into animal tissue when forced against it. The Alva pair, no doubt, experienced severe discomfort and some loss of circulation. Yet they completed two months of incubation, chick-rearing, and territorial defense and stand to survive their brushes with fishing line without permanent damage. Second, angling exacts a steady toll on loons and other wildlife. Loon populations are stable or perhaps even increasing slightly in northern Wisconsin. It is becoming obvious, though, that sustaining loon populations in areas where anglers are more abundant every year will require concerted efforts of those who love loons.

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Two days ago, Mark Naniot of Wild Instincts got a report that a loon on Two Sisters Lake had been hooked by a fisherman in the leg and was trailing 50 feet of monofilament line and a bobber. Mark learned also that a well-intentioned kayaker had approached the loon and cut much of the line, including the bobber, but leaving the hook and several yards of fishing line trailing. Having captured and unhooked a loon several weeks before on the same lake, we were disappointed to hear of another angling incident. Could the same bird have become entangled again?

Seth happened to be collecting data on Two Sisters Lake yesterday. He found the impacted loon, which was not the Two Sisters-West male that we had rescued in June but the female from Two Sisters-East. (The lake has east and west halves, each with a successful loon pair.) Seth reported that the female was using her right leg sparingly, trailing fishing line, and had tried but failed to take off and fly on several occasions. She was not with her mate and two young chicks. Clearly the bird was in trouble.

After digesting Mark and Seth’s reports, I turned my attention to the prospect of catching the impacted loon. I viewed the challenge with mixed feelings. On the one hand, this female, hatched on Crab Lake in Vilas County in 2004, was well-known to us as a rather tame individual, making capture more feasible. On the other hand, we had captured her four nights earlier, which raised the possibility that she would recall that event and be more difficult to approach a second time. The most crucial card we held was that the female had chicks to protect.

Several major research programs that focus on common loons in the northern U.S. and Canada rely, more than any other factor, on the ability to approach adult loons closely at night and net them when they have chicks. If researchers could not approach adults closely during this reproductive window, we would not be able to mark them and study their behavior, health or survival. We would therefore be unable to generate models to determine whether loon populations are increasing or decreasing. In short, loon research would grind to a halt without the presence of chicks to freeze adults on the surface and permit us to catch and mark them.

Last night’s adventure served as a vivid reminder of the value of chicks to adult capture. We began searching for the hooked female shortly after nine p.m. and located her quickly along the southwest corner of the lake’s eastern half. Her behavior was odd; she seemed to restrict her movements to one small portion of the lake and was not anywhere near her mate or two large chicks. She held her hooked leg out of the water when resting on the surface. Before full darkness, we spotlighted and approached her to attempt capture, but she repeatedly dove before we could get within a net’s reach. Although frustrating, this cheered us a bit, because it showed that she was still relatively healthy despite the hook. At the same time, we were vexed to see that a loon that was in dire need of human assistance and which we had scooped out of the water with ease four nights before was resisting capture. We made several more passes by the female, until it became clear that the distance at which she dove was increasing rather than decreasing. We had a loon in need of help, a huge staff from Wild Instincts on shore waiting to assist it, and no obvious means of catching the bird. The critical ingredient missing was her chicks, which were nowhere nearby and which, we felt, might have held her on the surface and permitted us to net her.

We shut down the motor and listened. As luck would have it, an adult loon tremoloed far to the northwest, near the small bay where the Two Sisters-East pair had nested. Eric drove us up to the northwest corner, where, after 20 minutes of searching, we located the male and two chicks. Freshly banded from four nights before, the male and two strapping youngsters were nonetheless easy to net and pull into the boat. We set out southwards, where we had left the recalcitrant female, and released all three birds there. After several minutes of silence, the just-released male finally wailed and an answering tremolo came from 400 yards southeast. Again, we were in a bind, because the female had clearly swum a good distance away, where she would not soon encounter the chicks that we had released in hopes of capturing her. So again we netted a chick — leaving one near the male — and motored southeast to where we had heard the female. Having glimpsed the female for an instant before she dove, we gently held the chick in the boat until it vocalized. The injured female was transformed: she immediately sat up in the water, alert, and wailed to call her chick to her. We released the chick, the two reunited, and the female remained alert and protective next to her chick as we slowly approached and netted her.

After all of our efforts, it was rewarding to learn that, while the hook had punched cleanly through the female’s leg a few centimeters above her colored leg bands (see photo, courtesy of Wild Instincts), the prognosis (according to Mark) was excellent for recovery.

Looking back, we spent three hours capturing a family of loons that we had just caught and banded four days earlier. The rescue was a major production, requiring us not merely to locate and capture her but to find and capture her family in a remote location on the lake and transport them to her vicinity in order to restore her parental instincts and permit us to approach and net the impacted loon. This effort threw a wrench in our capture schedule, necessitating that we rush to three more lakes to capture loons there and cancel plans to attempt capture at two more lakes. Still, our team effort with Wild Instincts left us glowing; we had rescued a loon in peril and given her a chance to return to her life as a plucky protector of two young offspring.

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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.