To supplement to my recent post on White-rumps at Plum Island as a shorebird learning experience, Rick Heil thoughtfully emailed me that he thinks the color was staining on the birds faces from feeding at Stage Island, and that he has seen that before. He also agrees with the standard dates given for juvenile Whiterumps, as late September-October. He does not think we saw any juveniles at this date.
We had considered staining as a possible issue (because in part it really looks like a dye) but we did not see other species in the groups (essentially Semipal Sands) with similar color, which could be explained at least several different ways, but does not negate what Rick said.
What he said was more in keeping with my recollections (and photos) of juvenile White-rumps (without any apricot color) taken at Sandy Point in Septembers past. Regrettably, yesterday's photos of the clusters of shorebirds with orangish-faced Whiterumps are not really very helpful, though I will pore through them when time permits to see if there is anything there to add to this.
Thanks for your help, Rick. The learning experience continues and hopefully doesn't stop here.