The Indefatigable Female of Upper Kaubashine

I have often sung the praises of female loons. Females, you will recall, have much greater staying power than males do. Adults of both sexes face the constant threat of eviction, by younger, fitter individuals. Males fight desperately for their territory, retaining it at great cost and sometimes dying in its defense. Females, on the other hand, seem to keep defeat in perspective, retreating to a nearby lake after losing their territory and then going about the arduous process of reestablishing themselves on a new territory.

Even among females, the Upper Kaubashine female stands apart for her tenacity. One distinction is simply her age. Having been banded in the first year of my study, 1993, she is most likely at least 31 years old. She is, therefore, the oldest loon ever in our study area. What seems even more remarkable about the Upper Kaubashine female is her breeding success, which spans a quarter century, five different territories scattered across Oneida and Vilas Counties, and at least six mates. No other loon, male or female, can match the breadth of her breeding record.

The Upper Kaubashine female epitomizes the relentless efforts of female loons to reproduce. However, her story is not one of unbridled success, like that of the Townline male (pictured during capture from a few nights ago). The Townline male has been a success through holding his territory for 24-plus years and cranking out chicks there. The Upper Kaubashine female has achieved genetic immortality by a nomadic path — tirelessly relocating and re-pairing following repeated losses of territory and mate. After all, to achieve the lofty distinction of having bred on five different territories requires the ignominious distinction of having been evicted from four.

What is it about this female that set her on this reproductive odyssey? We do not have a complete answer, but size likely plays a role. Throughout her life she has weighed in at about 200 grams lighter than average, which puts her in the lowest quartile of female size. Most of the female intruders that have visited her various territories to challenge the Upper Kaubashine female for ownership have outweighed her. It stands to reason that she has lost more than her share of battles. Only her uncanny ability to establish herself as a breeder on one high-quality territory after another has allowed her to overcome her physical limitations and become a productive breeder.