We checked the nest at about 8:00 AM this morning and saw no eagles anywhere. We returned at about 9:30 AM, and Phil arrived at the same time. We saw one adult sitting on the nest. It briefly flew off and returned within a minute. After about five minutes it flew off again, this time to the east, circled effortlessly on the thermals, then flew westward directly over our heads at a considerable height, all the time calling. The tail appeared to be unmarked. If this field mark proves useful again this season, it may indicate that this was the female bird. Phil said he saw both roosting on the tree just west of the nest along the road, and also saw one carry green vegetation to the nest.
If anyone else sees evidence of nest building or mating, please report your observations here. Copulation has been documented about one week prior to egg laying. In the past three consecutive seasons, eggs were presumably laid on December 13, 18 and 11.