Caught up as I am in the mad scramble that teachers and students face at the end of the school year, I have been unable to keep up with events unfolding in the study area. I am sorry about that. Of course……I am also not in the study area, so I have to rely upon accounts of loon activity from Linda and others who are able to see the birds!
The loons in northern Wisconsin seem oblivious to the pandemic that is plaguing humans at the moment. They have their own problems to worry about: other loons, eagles, and their early-season nemesis, Simulium annulus. During the past week or so, populations of this black fly have exploded, causing headaches for loons across the study area. (Thanks to Greg and Al for their reports of fly activity on their lakes.)
You might wonder why I use the scientific name of the species of fly that harasses loons. When humans are pestered by insects, we often think of the little varmints generically. That is, we place biting insects into classes that represent several or dozens of species — mosquitoes, black flies, horseflies, no-see-ums. Our crude classification scheme makes sense, because the behaviors of different species, the habitats where we find them, the timing of their attacks, and our strategies for eluding them are often similar across species. But loons face a laser-focused attack by females of one species of black fly whose sole purpose in life is to find a loon, extract a blood meal, and nourish their eggs with it. I loved this photo that Linda sent me
several days ago, because it illustrates two intriguing biological patterns. On the one hand, Simulium annulus makes life a living hell for loons for a few weeks every spring, as one can see from the cloud of flies on and around the head of the male loon in the water. (This bird is trying to work up the gumption to get back on the eggs.) On the other hand, S. annulus leaves all other birds alone, even those in plain view a few meters away (note the carefree Canada Goose standing on the island in the upper left corner).
It has been a rather cool spring in northern Wisconsin, and that is bad news for loons, as cool weather keeps female S. annulus alive longer than usual and prolongs the window during which they harass incubating loons. Reports so far suggest that there will be widespread abandonments of first nesting attempts, although some breeding pairs — like Linda’s intrepid duo, Clune and Honey — are so far enduring the welts and refusing to give up on their eggs. The coming weeks will tell us whether 2020 is a horrendous year for black flies, like 2014; a bad one, like last year; or an average one, like 2018. It pains me to say it, folks, but we are hoping to be average!
Let me end on an up note — well….kind of an up note. Our paper that reports reduced chick production, lower survival of young adult loons, and a decline in our study population has been well-received by a scientific journal. Thanks to everyone who helped with the decades of data collection that culminated in these findings and to our many supporters (including many who follow this blog) who made our work possible. During this year and the next few, we hope to learn what is causing these declines and to see if we can do something about them.