The 365 days of 2017
That, my dear, is a juvenile Cooper's Hawk. Your feeder has indirectly attracted him. They prey on other birds, even as big as mourning doves. (They pluck them first; so if you see a pile of feathers on your lawn, you know who is responsible.)
I was wondering what it was - and see Scott's answer. Love his mottled chest. Great photo!
Soooo beautiful. Great visitor, great picture.