Does anyone know, is it even possible, to distinguish immature Ruby-throated Hummingbirds from females?  A male, with incipient gorget feathers should be easy, but...  I encounter window kills frequently at work, and am keeping track, but remain flummoxed by those white-throated mites, most of which show some uniform stippling.

Kurt Schwarz
HowCo
goawaybird at comcast dot net