Nella Schmidt submitted the following photo:
April 7.... Nest-building Whitebreasted Nuthatches...The male (I'm assuming) had some nesting material in his beak and as as he ascended, descended and circled the trunk, he shook his head continuously back and forth. The female ( presumed) watched him. Eventually he placed the material which I couldn't identify into the cavity. On my way home, when I stopped by shortly, the male had a white fluffy seed head in his beak, and again engaged in the same head movements while the female was occupied with arranging the nesting material in the cavity.