How to identify the Costa's Hummingbird

To correctly identify the Costa's Hummingbird (Calypte costae), check each of these features. Birds can be tricky: habit, habitat, and call often confirm a sighting that a single photo cannot.

Size at a glance

Length

7.5-9 cm (3.0-3.5 in)

Wingspan

10.8-11.4 cm (4.25-4.5 in)

Weight

2.3-3.5 g (0.08-0.12 oz)

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Males have an iridescent amethyst-purple gorget (throat patch) that flares out at the sides, extending to a pointed 'mustache' on the sides of the neck, and a matching purple crown. Their back is metallic green, and their underparts are whitish with green flanks. Females are duller, with a metallic green back, whitish underparts, and a small amount of iridescent purple on the throat, if any. Both sexes have a relatively short tail.

2. 2

   Beak shape

   Shape and color of the bill: a key field mark.

   Long, slender, and slightly decurved black bill.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Dark brown

4. 4

   Leg color

   Leg and foot color.

   Dark gray to black

5. 5

   Distinguishing features

   Standout features that separate this species.

   The male's distinctive amethyst-purple gorget and crown are unmistakable. Females are more challenging but can be identified by their small size, relatively short tail, and habitat preference.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juvenile males resemble adult females but may show a few iridescent purple feathers on the throat as they mature. Juvenile females are very similar to adult females.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   No significant seasonal plumage changes. The iridescence of the male's gorget and crown is always present.

8. 8

   Sexual dimorphism

   How males and females differ.

   Pronounced. Males are brightly colored with iridescent purple on the head and throat. Females are duller, primarily green above and whitish below, lacking the extensive iridescent purple.

Key field marks

• Male Gorget and Crown. Look for the brilliant, iridescent amethyst-purple gorget that extends to a pointed 'mustache' on the sides of the neck and covers the entire crown. This is the most definitive field mark for males.
• Size and Shape. Costa's Hummingbirds are small, compact hummingbirds with a relatively short tail and a slightly decurved bill.
• Female Plumage. Females are metallic green above and whitish below. Look for the absence of significant rufous on the flanks or tail, and a relatively plain throat, sometimes with a few iridescent purple flecks.
• Habitat. Their preference for arid, desert, and chaparral environments can be a strong clue, especially when distinguishing from species that prefer more humid or forested areas.
• Vocalizations. Listen for the male's distinctive, high-pitched, squeaky-toy-like whistle song, especially during courtship displays.

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