Tonight, due to a pesky squirrel, the owls only got to sing to each other.
The cavity the female has been using this week is also used by squirrels at different times of the year. Since she's been using this cavity, she has extended her normal fly out time by about thirty minutes. We've been postulating what has been causing the extended fly out times: pre-nesting behavior, the cold weather and high winds or the squirrels. Tonight we learned that squirrels are definitely part of the equation.
The male arrived before the female flew out, called to her, but she only called back. Tonight, a squirrel ran down the branch the cavity is in and looked inside. I think this caused the female to stay put and guard the cavity. (On past nights, she has waited until the squirrels in the adjoining tree quieted down before flying out.)
Somehow the male understood and went about his business, flying as he normally does south across the North Meadow.
Only after the squirrels were safely asleep, did the female emerge from the cavity. She flew out quickly but spent about an hour outside the cavity before returning inside.