Blue Obsession

Most of us have been there: determined to take the next step in life but thwarted in our efforts to do so. More often than not, another individual occupies the position we seek. That is the situation in which nine year-old W/G,B/S (hereafter “White-Green”), finds herself on Blue Lake.

Blue seems a good fit for White-Green. She grew up on Franklin Lake in Forest County, another large, clear-water lake 35 miles to the northeast. Since young males and females try to settle on breeding lakes similar to their natal ones, it is natural that White-Green should try to find a place on Blue.

But setting your sights on a goal and achieving it are two different things. Back in 2014, when she was only five years old, White-Green battled with the 15 year-old female from the Blue-West territory and lost. Since then, she has made sporadic attempts to evict her decade-older rival, failing each time. In 2016, she observed the violent overthrow of the male at Blue-Southeast by a younger rival. However, the carnage that ensued offered White-Green no opening at a breeding position at Blue-Southeast, although she paired briefly with the male evicted from that territory. Since then, we have so often seen White-Green on Blue Lake – and never on adjacent lakes that we also monitor — that she must live there, hiding out in the swath of unoccupied space between the two breeding pairs. And waiting.

She waits still. Two weeks ago, White-Green again challenged the Blue-West female, in what has become an annual ritual. I have begun to feel frustrated on White-Green’s behalf. Her many fruitless attempts at usurping a space recall times when I myself have been baffled in a crucial life pursuit. It would seem that the writing is on the wall: White-Green is not strong enough to subdue the breeding female at either end of the lake and seize their breeding position. Shouldn’t she move on? Isn’t she wasting valuable time in the prime of her life? As a biologist, I come at this from another angle, asking, “Could White-Green’s obsession with acquiring a territory on Blue Lake be evolutionarily advantageous?”

A precise answer to this question would require a calculation of evolutionary fitness benefits of fighting for a known resource versus turning her attention to a new target — a neighboring territory on Bobcat, Bolger, or Kawaguesaga. We do not have sufficient data to make such a quantitative comparison. However, White-Green’s “siege” of the Blue-West territory does highlight two quirky features of the loon breeding system that might help us understand her odd behavior.

Whether male or female, nonbreeding loons in search of a territory set their sights on a handful of them that they visit often, rather than casting a wide net that includes dozens of potential territories. We infer from the narrow scope of their search that young nonbreeders might use a strategy of sizing up territory owners, monitoring their condition regularly, and challenging them for ownership when they seem most vulnerable. (Of course, nonbreeders would prefer the low stress alternative of replacing a breeder that has died.) The tradeoffs of focusing on a small number of territories are clear. By getting to know the behavior of a few breeders well, young nonbreeders might be able to pick up subtle changes in breeder behavior that signal weakness and allow them to time their eviction attempts effectively. And conducting a narrow search might also permit a nonbreeder to learn about the illness or death of a territory owner rapidly, so that they can quickly mount a bid for the territory and claim it before others learn of the opportunity.

Another quirk of the loon breeding system is a female-biased sex ratio caused by greater longevity among females. That is, there are always more breeding females than breeding males in the population, since many males die young. The longer lives of females is a double-edged sword from their standpoint. On the one hand, there is vigorous competition for any female breeding vacancy that becomes available. On the other hand, females live long enough that what at first appears to be an unhealthy obsession with one territory or two might ultimately be rewarded.