I wonder if someone here can help me

[cyclonefence]

This morning (I'm in SE PA) a little bird--goldfinch size--landed on a small tree outside my window. It was nondescript grayish, with gray/black stripes. But it had a big bright yellow patch on its butt! This was not a goldfinch; I know what they look like in early spring before they get their yellow. It was shy and flew when I tried to get a closer look. This guy looked like somebody had painted a big yellow spot on his butt--not his tail, his/her backside. Roger Tory Peterson was no help; I'd hoped it was a Confusing Spring Warbler, but I couldn't find a picture that even remotely resembled it. Any ideas? It has not returned today, and we have heavy bird traffic here.

[gademocrat7]

1. That is a yellow rump warbler

Here in Atlanta we also call them butter butts.

[cyclonefence]

5. Thank you so much--"butter butt" is a perfect description n/t

[Irish_Dem]

2. It is a yellow-rumped warbler?

Also known as butter butt.

https://abcbirds.org/bird/yellow-rumped-warbler/#:~:text=The%20Yellow%2Drumped%20Warbler%20is,field%20mark%20throughout%20the%20year.

[Walleye]

3. That's right yellow rump warbler I had one on my porch a week or so ago. Unusual

[Irish_Dem]

4. I'll have to look for them.

Though I don't know if they will show me their butts.

[cyclonefence]

6. Thank you!

[AllaN01Bear]

7. lovely little flyer , thanks for link.