This looks like a Savannah Sparrow. Notice the yellow around the face. Not sure about the dark streak either but maybe the feathers are being blown and we are seeing some dark under-plumage. Here's a Savannah from Prince Edward Island last year.
Thanks Stephen and John.
Not use to see this species perching in trees, normally I have seen then on the grass, and the dark streak on the chest also gave me some problems with the ID.