Ruby-throated Hummingbirds have mostly grayish flanks rather than coppery like Rufous Hummingbirds. https://www.allaboutbirds.org/guide/Rufous_Hummingbird/species-compare/#:~:text=Ruby%2Dthroated%20Hummingbird-,Female,Rufous%20in%20western%20North%20America. The female Rufous and Ruby-throated look very … More