Sometimes during a night of capture, when we have finished color-banding a loon and are releasing it back into its territory with its family members, I say to the bird, half jokingly, “Welcome to the Loon Project”. But I mean it. Once we place colored leg bands on a loon, we start to feel a kinship with that loon and take an active interest in its well-being.
The bond we feel with each banded loon grows as team members report its trials and tribulations across many years of its life. “Red over blue-stripe on Lumen is soooo tame!”. “Omigosh, that female on Lumen was super aggressive when two intruders landed in her territory this morning”. “Red over blue-stripe really scared a kayaker that came too close to its chicks today”. “Red over blue-stripe fed its chicks 58 times during the hour I was observing the family; those chicks begged relentlessly.” “Red over blue-stripe just skulked around the southern end of the lake this morning while her mate foraged with a new unbanded female. She looked so bummed out.” “There is a new breeding female on Birch today; she is red over blue-stripe!”
Just as we mourn when a male or female is evicted from its territory by a young adult, we cheer when it bounces back and claims a new territory nearby with a new mate. If one of “our” loons should be injured by a lure or fishing line, we spring into action to save it.
Knowing and caring about our study animals makes it more enjoyable and rewarding to observe them. But the warmth and connection we feel towards our loons is really just a pleasant byproduct of a coldly pragmatic research philosophy: mark every loon you can, and track marked individuals obsessively throughout their lives.
Why are we so fixated on marking loons and studying marked individuals? Because marking and reobservation allows us to turn anecdote into science. If one watches five unmarked adult loons circling and diving together in early July on Brandy Lake, and two of the five birds yodel at each other, one might conclude that two members of the group must be males that became aggressive for some reason. If, on the other hand, the five loons are color-banded, we can begin to make inferences about behavior. We might observe that the group consists of two territorial pair members from Brandy and three intruders: a 3-year-old male floater reared on Johnson Lake, a 7-year-old male floater raised on Bullhead, and an 11-year-old female breeder from neighboring Arrowhead Lake. We might further note that the two yodelers are the 9-year-old territorial male and the Bullhead floater. And finally, we might observe that the 3-year-old and neighboring female fled from the group of 5 following the yodeling incident and flew off shortly afterwards, while the 7-year-old male engaged in many simultaneous dives with the male breeder and stayed 36 more minutes before departing from the lake.*
Of course, one visit to a breeding territory does not by itself lead to any useful scientific conclusions, even when loons are marked. But when this day’s observations are combined with those by scores of other field observers on hundreds of marked loons and thousands of early mornings, statistical patterns begin to emerge. Indeed, in a paper we just published, we document how floaters (nonbreeders too young to claim a territory) behave differently as they age, how territory owners tailor their aggressive behavior to floaters of different ages, and how loon parents optimize defense of chicks differently as they grow. So the accumulation of observations on marked, well-known loons made possible several steps forward in our understanding of territorial behavior.
Marked loon populations have value over and above the strides they help us make in understanding loon behavior. Since loon numbers have clearly declined in Wisconsin in recent years and apparently also among the less-well-known loons of Minnesota, our study animals in both states suddenly have special significance. In the coming years, we hope to use our study populations in Minnesota and Wisconsin to ascertain the causes of the declines and work with others who love loons to turn things around.
*Linda’s cool photo above is of Nelson Gould, a Chapman student, who worked with us for three years.