Gracie and George changed places at about 6:12 a.m. PST this morning, as the day broke over San Francisco.

I read on the message board that the female usually sits the eggs at night, so I assume it was George who came to relieve Gracie.

Before, when I thought I saw Gracie stretching and returning to the nest, I must have seen the birds exchanging places at about 11 a.m. PST. 5 hour shifts?