Identification can be very difficult on young Ruby-throats because they can show dark spots on the throat right from the nest or they can show none and develop them over time. Looking at this young bird you would think it's a female(young or old), but there's one very small indication that it's a male(no it's not that). There's one small black gorget feather below the eye and to the left. That one feather showed a laser beam flash every time the light reflected off it. He quickly got the name "Freckle". He was easy to identify from the others, as the young males develop very inconsistently. Some show a five o'clock shadow right from the nest, while others appear like a female for the first several days. Some are black evenly spotted throats, and some come in patchy.
The reason this matters me is because I can soon tell just how many young birds are showing up in my garden. They quickly get identified, given names, and then recognized each time they make an appearance.
There was one other indication that this young bird was a male. He chose to sit near the tops of the trees, making himself known, just after winning territory containing a feeder that hung about 10 feet below him.
N.E. of Edmonton, Alberta, Canada. Late August, 2017.
The lower image is another juvenile Ruby from a few years back. He shows a more consistent throat pattern.