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I am never prepared for chick loss. As a scientist, I know that the first several weeks of life are fraught with danger for loon chicks. Have they developed normally? Can they thermoregulate properly? Are they able to dodge eagles, muskies, and snapping turtles that can devour them when small? Are their parents aggressive and vigilant enough to keep intruders at bay, which might otherwise kill them with a few well-placed jabs? Is there sufficient food in their natal lake to sustain them and support their rapid growth? And these are merely the natural threats to chick survival.

As hazardous to chicks as natural dangers, or perhaps more so, are threats that humans pose. Sometimes these are direct impacts; humans drive their boats rapidly and often strike chicks, which cannot elude them as deftly as adults. Anglers’ lures and baits, recognized as unnatural and avoided by most adult loons, are sometimes gobbled up uncritically by chicks, which are just learning what they can and cannot eat and must gorge themselves in order to grow. The hooks — and especially lead jigs and sinkers that they ingest at such times — pose a grave risk to the youngsters. A more insidious and dire threat that we have seen recently is the decline in water clarity in northern Wisconsin in the past decade, which makes it difficult for chicks and parents to find food and likely explains much of the reproductive decline we have seen there. (We will soon determine whether water clarity is declining in loon lakes in Minnesota as well.)

Although I am acutely aware of the increasing dangers that loon chicks face, I struggle to adjust to the steady drip drip of chick mortality in Wisconsin and Minnesota. When the Rush-USA Point pair lost their chick, I reasoned, “Well, that territory gets high boat traffic; it is hard to keep a chick alive there.” I justified the loss of the Cross-National Loon Center chick and the two chicks hatched by the Rush-Hen pair in the same way. I was a bit numbed by the time I considered the loss of the two young chicks of the Eagle-East pair.

I find it easier to stomach brood reduction. When broods decrease from two chicks to one, I take solace in the survival of the remaining chick. So it went at Upper Whitefish-Steamboat, Ossie-Island, and Sand this year. Very often brood reduction of this kind comes about because food is limiting; the death of the smaller chick actually gives the larger chick a fighting chance to make it.

What stings the most is loss of chicks that have reached four weeks of age. In the past few days, two chicks that had attained this milestone perished in the Minnesota Study Area. (The NLC is awaiting necropsies on both individuals.) Quick inspection of the Lower Hay-Southeast chick that lost its life and washed ashore earlier this week showed what appeared to be traumatic injury on the back, suggestive of a propeller strike. When you consider that the Lower Hay-SE territory is right next to a major public boat landing, this likely cause makes sense. The second deceased chick, from Clear Lake, was 32% lower in mass than its sibling; thus it was falling far behind in acquiring food from its parents. So this looks like classic brood reduction. Indeed, Kate Marthens, one of our Minnesota field team, reported that this chick was not keeping up with its family on the day that it was found dead, an indication that brood reduction was imminent.

The significant increase in mortality of loon chicks of all ages (i.e. both younger and older than five weeks of age) is a hallmark of the current population decline in Wisconsin. I should be learning to cope with it — preparing myself to face it in Minnesota too, if our growing sample there reveals the same trend. But that is more easily said than done. It still hurts like the devil to lose a chick.

Featured photo — One of our largest chicks in Wisconsin is that on Little Bearskin Lake. It was alive and kicking as of this writing! (Molly Bustos, a Wisconsin intern, holds the bird.)

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Sometimes on our research project, we observe a rapid series of nasty events that defy explanation and really shake us up.

This happened to my field interns in Wisconsin. They were “roving” outside our normal study lakes, visiting lakes that are either on the fringes of our 110-lake study area or with little past history of supporting loons. On July 8th, Sarah and Claudia found an adult with a fishhook hanging out of its head on the left side, behind and below the ear. Sarah, Claudia, and Chris covered Little Bass Lake on the following day — and found what appeared to be a second loon with the exact same problem.

We have seen dozens of angling casualties at this point, but we had never seen two weird and very similar hookings in rapid succession. Our puzzlement increased one day later, when Claudia was alone on Dorothy and saw a third loon hooked in this peculiar and painful way. (The featured photos at the top are hers.)

When Claudia contacted me and Linda Grenzer and described what she had seen, we had brief paranoid thoughts, “Oh my god; someone is systematically casting at loon’s heads and hooking them!” (Linda tells me this has actually happened before.) Or, on a deeper rung of paranoia: “Someone is capturing loons, sticking hooks in their heads, and releasing them.”

Repeated visits to the three lakes by our team shed more light. When Linda and her husband, Kevin, attempted to capture the hooked Buffalo bird, they did not find it on the lake on one night. Linda and Kevin also observed what they are confident are two different loons with very similar hookings on Little Bass Lake on two separate nights.

Here is what I conclude. First, these are young birds — probably floaters — but clearly not territorial birds with strong ties to these lakes. They are doing what loons do between ages 2 and 7: they are drifting about but staying in the same general area. If you scrutinize the photos above, it seems apparent that the 1st (Buffalo) and 3rd loons (Dorothy) are the same. Each shows a hook embedded in the loon’s head in the vicinity of the left ear, a fishing snap and swivel hanging off of the hook, and no fishing line attached to the swivel. But the feathers obscure the wound itself. On the other hand, the middle photo from Little Bass shows what appears to be open, inflamed tissue, again with a naked snap and swivel dangling from a hook or lure. Linda and Kevin think that the middle loon is certainly a different bird. I think it might be the same bird, even though the wound looks different. Either way, the loon(s) are dealing well with what appears to be a severe injury, because they are flying from lake to lake and intruding into breeding territories (Dorothy), as they should be.

Speaking of coping well with injury, we had another unpleasant angling event in northern Wisconsin during the past week. A male marked by the DNR eleven years ago on a territory near Three Lakes became incapacitated and was taken for treatment by Wild Instincts in Rhinelander. Their X-ray photo reveals the problem — this bird has a treble hook lodged in its gizzard. The bird has bounced back and been released at this point, but the nasty treble hook and attached line is still inside him. (Removal, of course, would have involved extensive surgery likely to harm the bird further.) We can only hope that the male’s digestive system will grind down and pass these hooks eventually, as we have seen in other loons.

In short, loons have taken some hard punches recently, as we have come to expect at this peak fishing time. If they are lucky enough to avoid the death sentence of a swallowed lead sinker or jig, they can be remarkably resilient.