What was the original range of the Anna’s hummingbird?

The Anna’s hummingbird (Calypte anna) is a small, iridescent green and pink hummingbird found along the west coast of North America. Their name honors Anna Masséna, Duchess of Rivoli, an amateur ornithologist and collector of hummingbird specimens in the early 19th century. Anna’s hummingbirds were originally only found in a narrow strip along the coastal regions of California and northern Baja California.

Original Geographic Range

The original breeding range of Anna’s hummingbird stretched from southeastern British Columbia in Canada to Baja California in Mexico. Within this range, they were most abundant in coastal and chaparral habitats in California. Their distribution followed the Pacific Coast and inland valleys and foothills. The core of their range centered around coastal southern California into Baja California.

Here are some more details on the boundaries of their historic range:

• Northern boundary: Southern Vancouver Island in British Columbia, Canada
• Eastern boundary: Western foothills of the Sierra Nevada Mountains in California
• Southern boundary: El Rosario, Baja California, Mexico
• Western boundary: Pacific Coast

So in summary, the original range formed a relatively narrow strip along the west coast of North America from Canada to Mexico. Within this strip, Anna’s hummingbirds were most abundant in coastal and chaparral habitats in California into Baja California.

Range Map

Here is a map showing the approximate original breeding range of the Anna’s hummingbird:

Habitats Within the Original Range

Within their historic range, Anna’s hummingbirds occupied a variety of habitats. Here are some of the key habitat types they were found in:

• Coastal scrub – Dense thickets of low shrubs and small trees near the ocean.
• Chaparral – Dry, dense shrubland areas away from the immediate coast.
• Riparian woodlands – Streamside forests dominated by sycamores, cottonwoods, and willows.
• Oak and pine woodlands – Scattered groves of oaks, pines, and other trees.
• Urban parks & gardens – Trees, shrubs, and flowering plants in city parks and backyards.

The mild coastal climate supported a diversity of nectar-rich flowering plants and trees. Anna’s hummingbirds depended on these plants for food and nesting sites within their preferred habitats.

Key Plant Species

Some of the important plant species that Anna’s hummingbirds relied on in their original habitats included:

Climate Within Original Range

The climate within the Anna’s hummingbird’s original range is characterized as having cool, wet winters and hot, dry summers. Proximity to the ocean moderates temperatures, keeping the weather relatively mild compared to inland areas.

Here are some typical climate conditions they experienced across their historic range:

• Average winter lows around 5°C to 10°C (40°F to 50°F)
• Average summer highs around 21°C to 27°C (70°F to 80°F)
• Annual precipitation 25-75 cm (10-30 inches)
• Majority of rain falls November to April
• Frequent fog along immediate coastline

The relatively mild Mediterranean climate provided Anna’s hummingbirds with a long breeding season. The abundance of flowering plants and nectar sustained them year-round within their narrow coastal range.

Seasonal Movements

Most Anna’s hummingbirds occupied the southern half of their range year-round. Those breeding farther north exhibited some seasonal movements. Their typical pattern of migration included:

• Northern populations migrated south in fall, arriving in California by November
• Southward migration stretched down Baja California and along the mainland coast
• Returned north by February to arrive on breeding grounds by March/April
• Males arrived on breeding areas a few weeks earlier than females

Breeding birds were relatively sedentary and did not migrate. It was primarily the northern fringe population that moved south in winter while central and southern groups remained resident year-round.

Summary of Original Range & Habitat

In summary, the original range of Anna’s hummingbird stretched along a narrow coastal strip from Canada to Mexico:

• Bred primarily in coastal California into Baja California
• Inhabited coastal scrub, chaparral, riparian, and open woodlands
• Dependent on diverse flowering plants like lilacs, fuchsias, and sycamores
• Mediterranean climate provided mild temps, winter rains, summer drought
• Northern populations migrated south in winter while central/southern were resident

This Pacific coastal habitat provided everything Anna’s hummingbirds needed to flourish including food, nest sites, and moderate climatic conditions. They thrived in these environments long before human settlement or development altered their original habitat range.

Range Expansion and New Habitats

Since the early 1900s, Anna’s hummingbirds have greatly expanded their range northward and inland. Their ability to adapt to human-altered environments enabled this dramatic expansion. Here are some key factors in their range growth:

• Increasing urbanization provided new habitat opportunities
• Backyard bird feeders supplemented natural food sources
• Residential flowering plants supplied nectar and insects
• Trees and shrubs offered nesting sites and shelter
• Warmer winters in urban heat islands allowed overwintering

As a result, Anna’s hummingbirds rapidly colonized new habitat across much of western North America in just decades. Their range now stretches from southern British Columbia down to Baja California, and as far inland as Arizona and New Mexico.

Current Breeding Range

This map shows how the breeding range of Anna’s hummingbird has expanded since about 1900:

In their new habitats, Anna’s hummingbirds sometimes face competition from other hummingbird species adapted to those environments. But they continue to thrive due to their generalist diets and ability to adapt to backyard feeders and gardens.

Threats and Conservation

Despite expanding their range successfully in recent decades, Anna’s hummingbirds still face some key conservation threats:

• Habitat loss from coastal development and urbanization
• Climate change impacts on flowering plants and nectar availability
• Pesticides and herbicides reducing insect food sources
• Window collisions in urban areas
• Competition with non-native birds at feeders

Some steps that can help protect and support Anna’s hummingbird populations include:

• Preserving natural habitats like coastal scrub
• Landscaping with native plants that provide food and shelter
• Avoiding pesticides to protect insect populations
• Installing screens on windows to prevent collisions
• Supplying clean feeders with sugar-water in gardens

Outreach to homeowners on making their yards bird-friendly habitats supports Anna’s hummingbirds and other urban wildlife. Continued research and monitoring is also needed to track the long-term impacts of climate change and urbanization on hummingbird populations.

Citizen Science Opportunities

Here are a couple citizen science programs people can participate in to help study and conserve Anna’s hummingbirds:

Contributing observations and data as a citizen scientist assists scientists in better understanding hummingbird ecology and how to protect these special birds.

Conclusion

In conclusion, Anna’s hummingbirds historically occupied a narrow coastal range along the Pacific Coast from Canada to Mexico. They inhabited scrubland, chaparral, riparian, and open woodland habitats rich in flowering plants. The mild climate with winter rains and summer drought was ideal for year-round residency for most populations. In recent decades, Anna’s hummingbirds have greatly expanded their range by adapting to human-modified environments. They now breed across much of western North America from southern Canada to Mexico. Continued habitat conservation and citizen science efforts will help ensure Anna’s hummingbirds continue thriving in both their historic and newly expanded ranges.