Today near noon I was checking an area in the South Park condo development along West Long Avenue in Littleton, near Long x Mineral. There are many trees in this development, with pines being quite numerous. So I was thinking maybe warblers. I was checking along the paths in the development and found it very quiet. But pishing here and there as I went, an *Audubon's Yellow-rumped* flew in, followed quickly by more and then there were 5 of them, and then 7, and then at least 12 Yellow-rumpeds were all around. I could count them as they flew over between trees. Eleven were Audubon's and one was Myrtle. Then with them there was a *Palm Warbler*! And after a little while a *Pine Warbler *flew into a pine near the yellow-rumped activity, remaining for a minute at most before flying out of view. And a *Ruby-crowned Kinglet *was with the flock. I don't recall encountering an actual warbler *flock* in late fall round these parts.