Both Anna’s hummingbird (Calypte anna) and the Ruby-throated hummingbird (Archilochus colubris) are small, fast-flying birds specialized for hovering and feeding on flower nectar. However, there are some key differences between these two hummingbird species in terms of their physical features, habitat, diet, courtship displays, and more.
Physical Features
In terms of physical appearance, Anna’s hummingbirds can be distinguished from Ruby-throated hummingbirds by the following characteristics:
- Size: Anna’s hummingbirds are slightly larger, measuring 3.5-4 inches long on average compared to 3-3.5 inches for Ruby-throated hummingbirds.
- Bill shape: Anna’s hummingbirds have thinner, straighter bills compared to the more dagger-shaped bills of Ruby-throats.
- Throat coloring: Male Anna’s hummingbirds have iridescent rose-pink throats, while male Ruby-throats have bright metallic red throats (females of both species lack throat coloring).
- Crown and head feathers: Anna’s hummingbirds have green crowns and grey-green head feathers compared to the greener head of the Ruby-throat.
- Tail shape and color: Anna’s hummingbirds have forked tails with white tips on the outer tail feathers. Ruby-throats have square-shaped tails with no white markings.
In summary, the key physical differences are the larger size, thinner bill, pink throat, and forked tail of the Anna’s hummingbird versus the smaller size, dagger bill shape, red throat, and square tail of the Ruby-throated hummingbird. Females are more difficult to distinguish visually.
Habitat and Range
Anna’s and Ruby-throated hummingbirds also differ significantly in their habitat preferences and geographic ranges:
- Anna’s hummingbirds are found along the west coast of North America from southern British Columbia to Baja California. Their range centers on California.
- Ruby-throated hummingbirds have the largest breeding range of any North American hummingbird, distributed across eastern North America from Nova Scotia to Florida and west to the Great Plains.
- Anna’s hummingbirds prefer open woodlands, mountain meadows, suburban gardens, and chaparral habitat, especially around flowering plants. Ruby-throats favor deciduous and mixed forests as well as gardens and parks with flowers.
- Anna’s hummingbirds are non-migratory, staying year-round in their western habitat. Ruby-throats migrate long distances, wintering in Central America and Mexico.
So in summary, Anna’s are found along the west coast and Ruby-throats in the east and Midwest, with very little overlap. Anna’s prefer open habitat while Ruby-throats live in forests. Anna’s are non-migratory compared to the migratory Ruby-throated hummingbird.
Diet
The diets of Anna’s and Ruby-throated hummingbirds share some similarities but also have some key differences:
- Both species get most of their nutrition from drinking nectar from tubular flowers such as columbines, bee balms, and trumpet vines. They also eat small insects and spiders.
- Anna’s hummingbirds have adapted to take advantage of bird feeders as a food source, especially in urban and suburban areas. They get a substantial amount of their nutrition from sugar-water blends at feeders.
- Ruby-throats rely more heavily on natural sources of nectar from wildflowers across their migratory range, although they will also visit feeders.
- Anna’s hummingbirds also occasionally eat tree sap, a food source not commonly used by Ruby-throats.
In summary, both species rely on nectar and insects but Anna’s hummingbirds make greater use of urban feeders while Ruby-throated hummingbirds depend more on finding wildflowers across their migratory range.
Breeding and Courtship
The breeding ecology and courtship behaviors of Anna’s vs Ruby-throated hummingbirds reveal some interesting differences:
- Anna’s hummingbirds breed between November and June depending on latitude, with two broods per season. Ruby-throats breed between March and July, with a single brood.
- Male Anna’s hummingbirds perform elaborate courtship dives up to 130 feet in the air before diving back towards the female at high speeds with a distinctive chirp. Ruby-throats do not perform dive displays.
- Ruby-throated hummingbird courtship consists of the male performing pendulum displays in front of the female, flying in U-shaped patterns while vocalizing with chirps and buzzes.
- Female Anna’s hummingbirds collect all nest materials and build the nest on their own. Ruby-throated females build the nest but males may assist in gathering materials.
- Nest placement also differs, with Anna’s nests located higher up, on exposed branches up to 20 feet high. Ruby-throat nests are lower, usually under 10 feet high along a protected branch.
In summary, courtship displays by the males, nest construction, placement height, and number of broods per season differ substantially between the species. Anna’s hummingbirds have a more drawn-out breeding season, elaborate dive displays, and higher nests compared to Ruby-throats.
Vocalizations
The sounds and vocal repertoire of Anna’s and Ruby-throated hummingbirds also provide distinguishing features:
- Male Anna’s hummingbirds produce a loud, buzzy series of chirps during their courtship dives. Their buzz has a lower pitch than the similar courtship sound made by Ruby-throated males.
- Ruby-throats have a very high-pitched, insect-like “chip” call used in courtship. This call is minimal or absent in Anna’s hummingbirds.
- Both species make clicking and whistling sounds with their wings in flight, but the wing sounds are louder in Anna’s hummingbirds during courtship dives.
- The distinctive courtship “song” vocalized by male Ruby-throats is longer and more complex compared to the simpler buzzing sounds of male Anna’s.
In summary, Anna’s hummingbird vocalizations are lower-pitched, buzzier, and typically less complex than the extremely high-pitched chip notes, whistles, and courtship songs produced by male Ruby-throated hummingbirds during breeding.
Migration
Perhaps the most pronounced difference between Anna’s and Ruby-throated hummingbirds relates to their migration habits:
- Ruby-throated hummingbirds are long-distance neotropical migrants, breeding across eastern North America but traveling south to spend winters in Central America or Mexico. Their annual migrations can cover thousands of miles.
- In contrast, Anna’s hummingbirds are permanent residents throughout their range in the west. They may migrate short distances seasonally but do not make the immense transcontinental journeys of Ruby-throats.
- Ruby-throated hummingbirds begin migrating north to their breeding grounds as early as January and February. The migration peaks in April but stragglers may arrive as late as early June.
- Southward fall migration of Ruby-throats occurs between August and October, peaking in September. Some juveniles get lost and end up straying to the west coast during migration.
- Anna’s hummingbirds maintain year-round residency and defend feeding territories in their home range. Any seasonal movements are localized altitudinal migrations driven by flower availability.
In essence, the migratory versus resident habits of these species define a major ecological difference between them. Anna’s hummingbirds remain in the west year-round while Ruby-throats make epic seasonal journeys between the eastern US and Central America.
Size and Mass Comparison
Here is a comparison table summarizing the average size differences between male and female Anna’s hummingbirds versus Ruby-throated hummingbirds:
| Species | Sex | Total length (in) | Wingspan (in) | Weight (g) |
|---|---|---|---|---|
| Anna’s | Male | 3.9 | 4.7 | 3.4 |
| Anna’s | Female | 3.8 | 4.1 | 3.5 |
| Ruby-throated | Male | 3.1 | 3.1 | 2.4 |
| Ruby-throated | Female | 3.5 | 3.5 | 2.9 |
As seen in the table, Anna’s hummingbirds of both sexes average distinctly larger in length, wingspan, and weight compared to Ruby-throated hummingbirds. The size difference likely contributes to some of the behavioral and ecological differences between these species.
Geographic Range Comparison
This map helps illustrate the very different geographic ranges occupied by Anna’s vs Ruby-throated hummingbirds in North America:
Source: greennature.com
As shown on the range map, there is essentially no overlap between the distributions of these species. Anna’s hummingbirds are restricted to the west coast while Ruby-throats occupy the entire eastern half of the continent. This geographic separation is a key factor underlying many of their behavioral and habitat differences.
Conclusion
In summary, while Anna’s and Ruby-throated hummingbirds are both diminutive, nectar-feeding members of the Trochilidae family, they exhibit numerous distinctive features when compared side by side. Key differences include size and proportions, geographic distribution, habitat preferences, migration habits, vocalizations, courtship displays, and more. Ruby-throats are smaller and migrate long distances between the eastern US and Central America. Anna’s are larger, non-migratory, and found exclusively along the west coast. These and other differences underscore how two species filling essentially the same ecological niche can adapt and specialize in very different ways. By understanding these variations, birders and hummingbird enthusiasts can more easily distinguish between these often-confused species.
