Anna’s hummingbirds (Calypte anna) are year-round residents of northern California, but they weren’t always. Prior to the mid-20th century, northern Baja California and Southern California were the only places that Anna’s would breed. Hummingbirds have long thin bills and even longer tongues that enable them to reach nectar that most other birds can’t get in narrow tubular flowers, such as monkey flower and manzanita. So their breeding habitat expanded when Californians planted exotic nectar-rich flowering plants in their gardens and hung hummingbird feeders outside.

Allen’s Coming to Town

Anna’s hummingbirds are among the most common hummingbirds along the Pacific Coast, but they are certainly not the only ones. Allen’s hummingbirds (Selasphorus sasin) visit coastal California for their yearly migration from central Mexico. They breed along a strip of coastal California and southern Oregon that includes Santa Cruz.

When they arrive, they make their presence known fairly aggressively. These three-inch birds are extremely feisty for their size, sometimes taking their rivals to the ground. Allen’s hummingbirds are even bold enough to chase off red-tailed hawks and American kestrels from their territories.

At the University of California, Santa Cruz (UCSC) annual Hummingbird Days, Scott Adam described the arrival of the aggressive Allen’s this way:

“When they first arrive, there is a big territory war. They forcibly displace the Anna’s hummingbirds into the surrounding neighborhoods, take possession of the nectar-rich grevilleas in the Australian garden, and then wait for the females.”

The arboretum at UCSC is a hot spot for both the Anna’s and Allen’s hummingbirds because it contains several non-native Australian flowering plants that provide a good source of nectar.