After 36 days, approaching 10 days past the expected hatch, the incubating loon pair continues to sit through temperatures in the mid-80s. This is hard work. Less than 3% of all nest attempts we’ve recorded over the past four decades have gone past the 5th week, like this one.  As we watch, and watch….and watch this loon pair, their stick-to-itiveness underscores an evolutionary tradeoff.  Their efforts at this point, for this nest attempt, are a costly mistake. But in the process of natural selection, the risks and energetic costs that would select against overincubation are, with each additional day, more and more clearly outweighed by all the advantages that come with an unyielding drive to tend the nest.