Size, shape, and yellow markings make it a Yellow-Rumped Warbler but I’ve never seen a YRW with so much black and black spots before. From what I’ve dug up online, apparently they go through a radical spring molting change like this so I assume the looks will smooth out and settle down. Canon FDn 80-200/4.0-L on NEX-7 View attachment 58561 View attachment 58562 View attachment 58563
When you mentioned washing machine, I thought for sure the bird would look more like this one... {} Sorry it's not as sharp and clear as yours is.