This tiny hummingbird is so light that it can balance on the edge of a leaf without bending it. It is extremely difficult to distinguish between female or immature male Scintillant and Volcano Hummingbirds. If it is an immature male Scintillant, its throat will become brilliant orange-red on reaching maturity. The adult male Volcano Hummingbird's throat is a much duller slaty-purple.