well-known individuals

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Now…I am a long-time fisherman. Since I was a young boy, I have enjoyed throwing a line in the water and imagining the lunkers waiting to strike my lure. (I think it started with McElligot’s Pool, the fantastic Dr. Seuss book that my parents read to me and my sibs.) I have spent many fruitless hours fishing — and enjoyed every minute of it. But my lifelong love of fishing has taken some bruises lately, as it has become increasingly clear that many loons in northern Wisconsin die horribly each year after entanglement in fishing line. I discussed some such incidents last year, but we have already had a recurrence of the problem this summer.

The most recent casualty is the territorial male on Jersey City Flowage. We had become rather fond of this bird, whom we banded as a chick on Swamp Lake in 1995. Year after year he and his mates have reared chicks on the Flowage, taking advantage of the abundant marshy habitat and network of islands there. He is tame, permitting us to approach closely and identify him whenever we care to. I vividly recall an occasion in 2005, when I found him foraging with his big strapping chicks. Neither he nor his juveniles cared a whit when my canoe approached them. They all foraged peacefully, oblivious to me. Here is a photo — a rather poor one — that I took Image

of the foraging family on that day.

Our team noted a month ago that the male had not returned to his territory in 2014. We were disappointed at the loss of cherished individual, but accepted that he had died over the winter or on migration or, perhaps, been evicted by another male this spring. Such are the perils faced by loons. But Marge Gibson of Raptor Education Group, Inc. notified us last week that her group had picked up a badly injured and emaciated male from a lake near Tomahawk, Wisconsin which turned out to be this male. He had swallowed two lead sinkers and, as you see, had become irrevocably entangled in the attached monofilament line.  Image

Although this bird had lost 25% of his body weight (down to 3400 g from his normal 4500 g) and was in desperate shape, Marge reports that the REGI staff were able to disentangle him, remove the lead sinkers, and get his weight back up to 3800 g with vigorous feedings. They were also able to repair his bisected tongue and restore blood flow to it. Recently, he was released near his old territory. Although it is always tricky to rehab a bird in such a weakened condition, we are allowing ourselves to hope that he will recover and will let you know what we learn of his health and territorial status. (He has lost his territory, and the new male there and his mate are nesting, according to Linda Grenzer, our tireless citizen scientist. So it will be a long road back for the injured male, even if he does return to health.)

I think that I will always enjoy the unique mixture of natural beauty, solitude, and occasional surge of adrenaline that I have enjoyed while fishing. But I will never again use lead tackle, especially now that there are many appealing alternatives. Help me spread the word about them!

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We just got a report that a pair of our loons is back, and this is the first pair of the year. Up to now, our pairs have had to content themselves with overflights of their territories to look for open water, which would allow them to land. At other times, they wait (mostly along the Wisconsin River) for their lake to open up. But according to Linda Grenzer, who is super hawk-eyed and on the ball, about 20% of her lake (Muskellunge in Lincoln County) was ice-free by this afternoon, and that was enough to permit the banded pair there to land and begin to defend the territory anew.

The Muskellunge pair that Linda found today is well known to us. The male there is a very tame bird whom we banded on as a chick on Manson Lake in 1998 and who produced chicks with a first female on Deer Lake in 2003 and then bred successfully with her again there in 2004 and 2005. In 2006 and 2007, Deer yielded no chicks. As we have seen with numerous other males, this male then gave up on Deer, evicted the male on Muskellunge (right next door!) in 2008 and paired with a new female there. He has twice produced chicks on Muskellunge and seems firmly ensconced there now. The Muskellunge female is also an interesting individual, as Linda caught her spending some of last summer hanging out with and feeding a chick from Clear Lake (also next door to Muskellunge) when her own chick had shifted to a new lake! Furthermore, Linda photographed this female while she was molting, and I posted the photos on Nov. 28 of last year.) Kudos to Linda for all of the sleuthing. I do not believe her breeding loons do anything interesting without her recording it from her kayak nearby.

Since this post has become mostly a tribute to Linda’s great field work, it is fitting to end up with a photo she sent me a few weeks back. She took this photo on the Wisconsin River near Tomahawk on 14 April. If you look closely, you will notice that one of the colored leg bands has a geolocator tag attached. The tag from this male, who is, by the way, from a territory up in Vilas County, will provide a good deal of information on his past migratory movements and foraging patterns that might help USGS biologists learn about the occurrence of avian botulism, which kills many loons.

 

 

Linda Grenzer photo from April 2014 Wisc River

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Well, the loons are gone from the study area. I know we all miss them. Each year I mourn after the loons migrate south and we all have hunkered down for the winter.

But research goes on. I am in the midst of an analysis to learn whether loons that have settled on one lake and bred there — either successfully or not — choose a second breeding lake that is similar to the first. What I am asking here, in effect, is whether a loon learns what constitutes a good breeding lake through its reproductive efforts and applies what it has learned in subsequent reproductive attempts. For example, a loon might first settle on a very clear lake, adapt to foraging on that lake, and then look for a second lake that is also clear. We have preliminary data to suggest such a pattern. If loons do learn what features of lakes are helpful to breeding, and fine tune their lake choices on the basis of their first territory settlements, this would be an interesting and important advance in the study of habitat selection. It would also add to our recent finding that loons initially choose to settle on breeding lakes that match the lakes on which they were reared.

I will let you know what I find out about territory settlement as the work progresses. Meanwhile, enjoy these nice photos from Linda Grenzer, who tracked the breeding female from her lake onto Bridge Lake this fall and caught her molting.

LMG_9523 Molting Loon LMG_9464 Molting Loon2

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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.

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We were sad to learn yesterday that one of our long-term resident birds has died. We are not sure what the cause of death is, but the DNR will do a necropsy at some point and share the results. When a vigorous and healthy adult suddenly succumbs to an unknown cause, as happened here, I always fear that a boat-strike or angling casualty might have occurred, but it is too early to know. All we know, thanks to the sleuthing of Georgia Eusebio, is that the male dragged himself onto shore, moribund, on August 23rd and died shortly afterwards at the Northwoods Wildlife Center. This male was a favorite of ours on the study, as he was  tame and relaxed during our behavioral observations, yet fiercely protective of his territory. He was also a long-distance disperser, having hatched in 1994 on Snipe Lake in Vilas County, which is about 5 miles WNW of Eagle River. His passing leaves his mate, who was banded on South Two in 1997, to care for the two strapping chicks, which are just learning to fly. We think they are old enough to survive losing their father. Gabby and Kristin will continue to follow them this fall, so we shall see.

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1991 was the first year that marking of loons occurred in our study area. In that year, Dave Evers and his crew captured and banded seven adult loons, five males and two females. It was not until two years later that I began my behavioral study of the population.

Of those seven marked adults, two survived for at least 15 years, but none had been observed for the past two years. I had given up hope that any of the “Magnificent Seven” was still alive.

All of that changed recently, when Kristin nailed the bands on the male that had been caught on Little Bearskin Lake in 1991, produced 14 fledged chicks between that year and 2005, and was finally evicted by a younger male in 2006. (He tried to breed on Heiress Lake in 2008, but his nest failed.) Last spotted in 2010, this old fellow is at least 26 years old. Here is how we know this: He was first spotted as an adult in 1991, and no adult has ever nested at an age younger than 4 years; so he must have hatched no later than 1987.

So….kudos to Kristin for IDing this old guy and especially to the old guy himself, the only remaining member of the Magnificent Seven.

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Although we were sad eight days ago, when we lost the male to an eagle on Tomahawk-Sunflower Bay, his sudden demise gave us an opportunity to observe what happens when an established breeder disappears. In this case, the unbanded mate of the dead male was on her own for a day or so and then was joined by a banded male that we know well. He is blue over orange (right leg), blue over silver (left leg) or “B/O,B/S”. B/O,B/S is the former breeder on Mud Lake, just next door. In late May of 2011, B/O,B/S picked up an orange fishing bobber on his right leg that slowed him down a little and affected his diving. We were very worried about him, as we thought that the bobber and associated monofilament line might cut off his circulation and cause him to lose his leg. We visited the territory often to check on him. He lost the Mud territory that year but remained in good health, it seemed. He was sometimes spotted on Bird Lake, just next door, so clearly he was able to fly. Now he has come full circle, as he has lost the bobber on his leg, recovered from that injury, and established himself again on a breeding territory. By the way, B/O,B/S is a male ABJ (Adult loon that was Banded as a Juvenile) that has a special place in my heart, because he is a “third-generation” loon to our study. He is the son of a female ABJ from Shallow Lake that was hatched and banded in 1993, my first year of research on loons. (This female is still around. After many years as the breeder on Fawn Lake, she is now a pair member on Lumen Lake.)

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This morning Kristin found the banded male on Tomahawk – Sunflower Bay freshly killed and being consumed by eagles. This is a sad discovery for us, because he was a sweet, tame bird with a rich history of rearing chicks — on two separate territories. We cannot be certain that an eagle killed the male, but he was healthy on our last visit, and the pair had recently nested. So we strongly suspect our national bird!

This is a reminder that, while they usually seem to be merely a nuisance, eagles DO have the potential to kill adult loons. Our best-documented example of an adult kill was a female attacked and dispatched by an eagle on a nest on Alva Lake back in 2005. Of course, eagles are a constant threat to chicks.

Funny, but I have struggled to love our national symbol recently. I hope that does not sound unpatriotic!