I didn't know before this fall that Black-headed Grosbeaks could be so social. We have four of them coming to our feeders on a daily basis, and it's obvious they are hanging out together, as they often come as a group, and they are completely tolerant of each other, sometimes all on the same feeder. They are all presumably birds of the year, and I suppose it is even possible they are siblings, although the species doesn't breed right around our yard, and these birds first appeared on Aug 17, quite a while after I would have thought fledging took place and more like fall migration. The birds vary only slightly, mostly in brightness of the orange underparts, and the literature says that first-winter males average brighter than females, so I suppose we have both sexes.

Dennis Paulson
Seattle, WA