Male and female Anna's hummingbirds have distinct appearances. Males are easily identified by their vibrant, iridescent reddish-pink crown and gorget (throat), which can appear dark in low light. Females have a more muted appearance, with green backs and gray underparts, and may have some red spotting on the throat.

Male:
• Head: Iridescent reddish-pink crown and gorget (throat), which can appear dark or black in certain light.
• Body: Bronze-green back, gray underparts, and green flanks.
• Tail: Dark, slightly forked tail.

Female:
• Head: Green, with a small amount of red on the throat.
• Body: Bronze-green back, gray underparts, and green flanks.
• Tail: Dark tail with white tips on the outer feathers.

Key Differences:
• The most noticeable difference is the male's bright red head and throat, which is not present on the female.
• Females have a small amount of red on their throats, but it is not as extensive or vibrant as the male's gorget.
• The tails are also different, with the male's being dark and slightly forked, while the female's is dark with white tips.
• While both have green backs, the female's overall appearance is more muted and less colorful than the male's.