What is the difference between Anna’s hummingbird and Calliope?

Anna’s hummingbird (Calypte anna) and Calliope hummingbird (Selasphorus calliope) are two small, colorful hummingbird species found in western North America. Both are known for their iridescent plumage and rapid wing beats, but they have some key differences.

In the opening paragraphs, we’ll provide quick answers to some common questions about how Anna’s and Calliope’s hummingbirds differ:

• Range – Anna’s hummingbirds are found along the Pacific Coast from British Columbia to Baja California. Calliope hummingbirds have a more inland range in the western U.S. and southwestern Canada.
• Size – Calliope hummingbirds are the smallest breeding bird in North America at about 3 inches long. Anna’s hummingbirds are slightly larger at 3-4 inches.
• Appearance – Male Anna’s hummingbirds have rose-pink throats and crowns. Male Calliope’s have vibrant magenta-colored throat feathers called a gorget.
• Behavior – Anna’s hummingbirds are aggressive and territorial. Calliope’s are more timid and prefer open habitats.
• Habitat – Anna’s hummingbirds thrive in urban and suburban gardens. Calliope’s prefer mountain meadows and pine forests.
• Diet – Both subsist primarily on nectar and small insects, spiders, and tree sap.
• Conservation – Neither species is of significant conservation concern. Anna’s hummingbirds are expanding their range northward.

Now let’s take a deeper dive into how these two hummingbirds differ in terms of range, physical description, behavior, habitat, diet, and conservation status.

Range and Distribution

Anna’s and Calliope’s hummingbirds have broadly overlapping ranges across much of the western United States and southwestern Canada. However, there are some key differences:

• Anna’s hummingbirds are found along the entire Pacific Coast from southern British Columbia to Baja California. They are common year-round residents of coastal California and the Southwest.
• Calliope hummingbirds have a more inland range centered on the Rocky Mountains from southern British Columbia through Idaho, Wyoming, and Colorado. They migrate south in winter to Mexico.
• In California, Anna’s hummingbirds are statewide, while Calliope’s are restricted to higher elevations in the Sierra Nevada range.
• The two species may overlap in areas of southern Oregon, California’s central coast, and the Columbia River Gorge.

In summary, Anna’s hummingbirds occupy coastal and lowland habitats while Calliope’s penetrate further inland and to higher elevations of the western mountains. But their breeding ranges do broadly converge along some inland corridors.

Physical Description and Size

One major difference between the species is their size. Here’s how they compare:

• Calliope hummingbirds are the smallest breeding birds in North America. They measure just 2.75-3.5 inches (7-9 cm) long with a wingspan of 4 inches (10 cm).
• Anna’s hummingbirds are noticeably larger at 3.5-4.3 inches (9-11 cm) in length with a wingspan up to 5 inches (12 cm).
• This size difference means Calliope’s weigh only 2-3 grams compared to 3-6 grams for adult male Anna’s.

In terms of plumage, both species display sexual dimorphism where the males have the most colorful, iridescent feathers:

• Male Anna’s hummingbirds have a bright magenta head and throat with emerald green back feathers. The throat may appear reddish-pink rather than magenta in some lighting.
• Male Calliope’s have vibrant magenta throat feathers called a gorget. The crown and back feathers are a mix of metallic green and bronze tones.
• Females of both species lack the bold throat and crown colors. They are primarily gray-green overall with white undersides dotted with green and reddish-brown flecks.

The following table summarizes the key physical differences between the species:

So in summary, Calliope hummingbirds are noticeably smaller than Anna’s, and the males have different throat and crown color patterns. But females and juveniles are very similar between the two species.

Behavioral Differences

Anna’s and Calliope’s hummingbirds differ in some aspects of their behavior, particularly in their feeding and territoriality:

• Anna’s hummingbirds are highly aggressive and territorial, especially the males. They will vigorously defend feeding sites and nest sites against intruders.
• Calliope hummingbirds are more timid and less apt to fight. They will avoid confrontations over food and territory when possible.
• Male Anna’s engage in elaborate courtship displays, flying in U-shaped or J-shaped dives to impress females.
• Calliope courtship displays are more subdued. Males fly in wide circles above females while singing a high-pitched song.
• Anna’s hummingbirds are trapliners, establishing feeding circuits of favorite nectar sources. Calliope’s move more randomly between food plants.
• Both species occasionally consume small insects for protein. But this makes up a larger portion of the diet for Calliope hummingbirds compared to Anna’s.

The territorial nature of Anna’s hummingbirds allows them to thrive in urban and suburban settings. Calliope hummingbirds prefer more open, rural habitats away from aggressive Anna’s.

Preferred Habitats

The habitat preferences of Anna’s vs. Calliope hummingbirds also differ considerably:

• Anna’s hummingbirds readily adapt to urbanization and human disturbance. They frequent gardens, parks, backyards, and flowering landscaping trees in cities and suburbs.
• Calliope hummingbirds mostly avoid developed areas. They prefer open mountain meadows, pine and fir forests, canyon streamsides, and other rural or wilderness settings.
• Anna’s hummingbirds occur across a wide range of elevations from sea level up to around 10,000 feet.
• Calliope hummingbirds are typically found between 4,000-12,000 feet in mountainous terrain. They migrate to lower tropical elevations in winter.
• Anna’s hummingbirds thrive in coastal and inland habitats such as chaparral, woodlands, and desert oases.
• Calliope’s require cooler, moister environments than Anna’s and thus flourish in higher altitude mountain zones.

The affinity of Anna’s hummingbirds for human development enables them to occupy areas outside their native range. For example, they have expanded northward along the Pacific Coast into Canada where suitable urban gardens provide food and shelter. Calliope hummingbirds have not demonstrated the same ability to urbanize and expand their range.

Diet

Anna’s and Calliope hummingbirds have broadly similar dietary habits:

• Both species get most of their daily energy from flower nectar. They use their long bills and tongues to drink nectar while hovering at blossoms.
• Favorite nectar food plants include sages, currants, penstemons, fuchsias, and flowering trees like eucalyptus.
• To supplement nectar, they eat small insects such as gnats, aphids, and flies. Spider webs may also provide protein.
• Both species will occasionally drink tree sap for an energy boost.
• During migration and winter, Calliope’s rely more heavily on insects to meet energy needs when flowers are scarce.
• Anna’s hummingbirds get most food from flowers year-round because of their ability to occupy warmer, urban areas.

The bottom line is both hummingbirds have a liquid-dominant diet centered on flower nectar. But insect protein likely makes up a larger percentage of total food intake for Calliope hummingbirds compared to Anna’s. This reflects their differing habitat preferences.

Conservation Status

Neither Anna’s hummingbird nor Calliope hummingbird are considered threatened or endangered species currently. However, their conservation outlooks have some key differences:

• Anna’s hummingbird populations are growing and expanding their range northward thanks to uptake of exotic flowering plants in urban and suburban gardens.
• Calliope hummingbirds have a smaller overall population limited by their high elevation habitat. But their numbers are generally stable in most regions.
• Climate change could benefit Anna’s by increasing suitable warm-weather habitat, but may negatively impact Calliope’s alpine meadows.
• As year-round residents, Anna’s already occupy much of their potential range. Most expansion is likely to the north into Oregon and Canada.
• Calliope’s may shift their range northward in Canada, but this is constrained by geographical barriers and lack of mountains/meadows.
• Neither species is hunted or commercially traded. So direct human persecution is not a threat factor.

In summary, Anna’s hummingbirds appear best suited to adapt to habitat changes and urbanization. Calliope hummingbirds are more specialized in their montane habitat needs, likely making them more vulnerable to climate shifts and resource limitations.

Conclusion

In conclusion, Anna’s and Calliope’s hummingbirds overlap across much of the western U.S. and southwestern Canada. But they differ significantly in their size, physical appearance, behavior, preferred habitat, and conservation outlook.

Key differences include:

• Calliope hummingbirds are noticeably smaller than Anna’s hummingbirds.
• Male Anna’s have pinkish-red throats while male Calliope’s have violet-magenta gorgets.
• Anna’s hummingbirds are highly aggressive while Calliope’s are more timid and non-confrontational.
• Anna’s readily inhabit urban areas while Calliope’s strongly prefer undeveloped mountain meadows and forests.
• Anna’s hummingbird populations continue to expand while Calliope’s face more threats from climate and habitat change.

These behavioral and ecological differences help separate the two species across most of their breeding ranges. Hybridization can occasionally occur where the birds intermix along migration routes and in hybrid zones like California’s Sierra Nevada. But in general, Anna’s hummingbirds are well-adapted to lowland urbanization while Calliope’s require remote mountain meadow habitats to thrive.