Donna, as far as I know, the immature RT males do have the white throats but might have a speck of black on them. I noticed several like that a few years ago and assumed they were females with specks of black and thought, good deal, now I'll be able to ID these hummers! LOL! Needless to say, I later learned that what I was really seeing were juvenile males. It was LATE in the season, probably September, when I saw the young males with a black speck or two. I have no idea how long it takes for their true colors to develop by I assumed it would be several months after they've hatched.

I'm seeing lots of "what I think are" females right now. Some probably are young males. Janie

Hi Donna

I had asked the same question. The one with the red neck is an adult or passer thru. A bander related to me that ones with black spots or stripes on a white throat are young males and only the young males have that.