CLOSED: enough here for id?

I don't think this was one of the regular visitors to my yard. Photo taken August 22. Only photo I got and I'm afraid the focus was on the leaves instead of the bird. Shadows probably don't help either. Thanks for looking

Well, it would pretty much have to be a vireo since it's the size of a leaf, the colour of a leaf and behind a leaf... just kidding, though it might be a vireo...

Tough one without much indication of size or bill shape. My best guesses are either MacGillivray's Warbler, or female Summer Tanager.

Resin

Thanks, I was most disappointed that I wasn't able to get the bill in the photo
I do have another photo with a caveat or three:
1. Though this photo was taken just a few minutes later, I am not at all sure it is the exact same bird. I didn't see where the bird went and the tree it was in for this second photo is busy with birds.
2. Photo quality is worse but if you can make it out it does show the bill.
3. I am a terrible judge of size, bigger than a Verdin and smaller than a Dove - that is for sure, lol

1st tree was an Apricot, 2nd Thornless Honey Locust
I did have a flock Western Tanagers earlier in the summer. Main visitors at this time were Hummingbirds, various Orioles, Verdin, House Finch, Mockingbirds and Pyrrhuloxia. This bird was extremely quick to leave and I just caught flashes of it. I though it wasn't one of the regulars (unless it was an Oriole?) The yellow, size and shape seemed different.

I forgot to say you made me laugh altagardener "since it's the size of a leaf, the colour of a leaf and behind a leaf"
exactly!

I suspect that's the same bird, but it's still a tough one!

Resin

I know :-),
glad I gave it a go though because I've already wondered for 6 months. It will just remain a happy mystery.