Thanks Tracy for clearing that up. Been wondering sometimes when I see one bird leap off the ledge and then another one show up front and center. Until i could tell them apart, I always wondered if she just went for a (poopy) or something! and came right back, or was scaring off another predator. But after watching non stop except to go to bathroom for a few days, I started realizing that what I was seeilng had to be the switch.. SO I read every thing possible on this website to learn more, and then some. After reading how they were different around the head as well as size, I finally got confident enough to know who was on deck. I mean who is on the nest. lol. Now I feel very much involved and informed,, all thanks to you .. yahoo.. from Yoho.New Brunswick!