Take Nothing for Granted

A good birder and close viewer might have noticed the slight vest on the Eastern Kingbird in my earlier post with fieldsketches from today. The bird I drew didn't have this vest. But the kingbirds that perch in this location also perch at the top of a 70-80' tree 50 yards away. They do it every year. So when I was about to leave and saw a kingbird like bird in that tree I assumed it was either the same or another Eastern Kingbird. BUT it had a vest. It also had, or seemed to have, some rust on the underside of its tail. I assumed the vest must be due to it being an immature Eastern Kingbird.
I don't see that many juveniles so I just quietly made the assumption. AND I added it to the sketch I'd done of the Eastern Kingbird earlier. I wanted to note it even though it was a different bird. I just didn't think it was a different species! After I'd been home awhile I got out some guides to check on the rusty tail. Well I didn't find it. But I did find the Olive-sided Flycatcher. I've seen these a number of times, often calling to help me out, but still distinctive with their vests. I don't know why I didn't think of it when I saw this bird. Most likely because I just don't expect to see them in Philadelphia and I do expect to see Eastern Kingbirds in Philadelphia and even on this exact tree.
In any case I'm posting some of the distant photos I took today to see if I can get a confirmation from the PA Rare Birds List that this is an Olive-sided Flycatcher. And to ask if anyone's ever seen a rusty undertail. (A few hours later and yes it is an Olive-sided Flycatcher thanks to a couple of responses from the list. I've also retitled this post in case my sense of humor in the previous title just passed people by, as it often does....................)