Tags

, ,

In Linda‘s last round of photos from Bear Lake, you can see the numbers clearly. At the narrow end of the metal band, a fuzzy, curling “6” followed by a clear, swooping “2”. Those two digits — either one of them, actually — identify the Mystery Female of Bear Lake as the chick we banded on July 18, 2005 on North Nokomis Lake. This photo culminates several days during which Linda patiently stalked the female with her camera lens until the bird finally pulled her metal band out of water in an orientation that permitted Linda to photograph the two digits we needed to see from the nine-digit number code.

The story of the Mystery Female concerns more than just solid detective work and crisp photography; it relates to the crucial decisions that a loon must make while attempting to settle on the best possible breeding lake and rear as many offspring as possible. The Mystery Female, Orange over Mint-burgundy — OMb for short — faced such a decision. OMb returned to the study area as a 4-year-old in 2009 and began hunting for a place to breed. She settled on Upper Kaubashine (at the end of the long arrow below) in 2012 and lost clutches of eggs to predators there in both 2012 and 2013. OMb then

N Nokomis to Bear w UK also

faced a stark choice — remain on a poor territory attempting to breed or abandon Upper K and try to move to a more promising locale.

Shifting from a poor territory to a good one might seem like an easy call to make, but female loons must cope with a shortage of potential mates owing to early senescence and frequent fatal fighting in males. Every year we see many loner females, some of which live on good breeding lakes, waiting for a mate. So it is an open question whether a female should desert a mate and breeding territory — even a poor one — to try and move to a better location. You see, in trying to secure a new territory, a female must temporarily leave her current one, risking its loss to another female on the prowl.

OMb decided to abandon Upper Kaubashine in 2013, establishing herself as the new breeding female on Bear Lake (shorter red arrow), whose female had died. This appeared to be a wise move; Bear had yielded chicks in 9 of the previous 13 seasons, while Upper K had not fledged a chick in 35 years.

Chance plays a big role breeding success of loons, as in all animals. In a curious twist of fortune, Upper Kaubashine stunned lake residents by hatching two chicks from a terribly exposed nest site. Since Bear Lake only produced a single chick this year, OMb’s choice of Bear over Upper K looks like a poor one, as of now. But chick production in these two lakes will probably return to form. If so, and if OMb can hold onto her new territory, her decision to leave a perennial failure for a proven chick-producer will have been a good one.