I am still deciding how to feel about recent events. On the one hand, one of our marked females lost her mate and territory, beached herself on a lake shoreline, tolerated a lengthy car ride, survived a difficult surgery, and now faces an uncertain path to recovery. On the other hand, a crew from the Loon Project and veterinary staff from Raptor Education Group, Inc. rescued this bird from near death, transported her safely to the REGI facility, expended countless hours conducting major surgery, and is diligently nursing her back to health. These heroic efforts – especially those of the REGI staff and veterinarians — have transformed certain death into the prospect of full recovery.
As I struggle to process this troubling series of recent events, one image lingers. It is the x-ray below (provided by REGI) of the female’s gut seemingly stuffed with fishing tackle.
Foremost among the questions swirling around my brain is this one: Is ingestion of fishing tackle a common occurrence? That is, do many adult loons in northern Wisconsin have to contend with fishing gear they have swallowed while foraging?
Our understanding of lead poisoning, scrutiny of our field notes, and inspection of the fishing gear recovered from the female’s gut (in the photo from REGI) help in answering this question. Lead is a potent toxin in birds and mammals, causing severe impacts to nervous and digestive systems. Lead toxicosis, moreover, occurs shortly after loons ingest lead — a day or a few days later — not weeks or months after ingestion. Linda Grenzer reported the Mable female intruding on her lake on 20 June. So the female was flying normally three days before she became utterly helpless on Mable (23 June). Furthermore, the fishing tackle in the photo seems to represent that found on the end of one person’s line. So the Mable female apparently swallowed someone’s fishing line on about the 20th or 21st of June and quickly began to deteriorate. Viewed from a population perspective, this is good news, because it suggests that loons in our study area do not ingest lead sinkers very often. If they did, we would face the ghastly prospect of helpless, neurologically-impaired loons constantly casting themselves ashore on our lakes.
Having concluded that the plight of the Lake Mable female is the exception, not the rule, I have begun to breathe more easily. Loons face considerable hurdles in coping with fishing tackle in northern Wisconsin, but lead poisoning — as far as we can tell — seems to be somewhat less of a threat in the Upper Midwest than it is in other populations. So I will end this post on that cheerful note and with Linda’s cheerful photo of the 2019 Loon Project team, which has worked tirelessly to watch over our study population this summer.
