72 Microseasons of the Pacific Northwest

Anna's hummingbird (Calypte anna) is the only hummingbird that remains in the Pacific Northwest through winter, and by mid-November it has become the sole representative of its family across the region. A year-round resident of urban and suburban gardens from California to southwestern BC, Anna's hummingbird has dramatically expanded its winter range northward since the 1960s, aided by the proliferation of backyard feeders and winter-blooming ornamental plants. It is now a common sight even in greater Vancouver, BC. Unlike other hummingbirds that travel to Central America, Anna's hummingbirds enter torpor on cold nights, reducing their body temperature to just above ambient and dropping their heart rate from 1,200 beats per minute to fewer than 50, conserving energy through the cold hours. They resume full activity at dawn, often hovering in frost-tipped gardens before feeders are even unfrozen. What makes mid-November special is the blooming of Oregon grape (Mahonia aquifolium and M. nervosa), whose yellow flowers open through late autumn and winter and serve as a critical natural nectar source. Urban gardens with flowering heathers, winter jasmine, and mahonias become hummingbird territories. The male Anna's — a shimmering magenta-helmeted bird — will sing even in November, perching on exposed twigs and delivering a scratchy, surprisingly complex song on grey winter mornings. This is the bird's courtship and territorial song; males defend winter feeding territories aggressively, diving at intruders with an audible wing-whistle. Spotting an iridescent magenta Anna's hummingbird hovering against a grey November sky, with breath-plumes visible in the cold air, is one of the Pacific Northwest winter's most charming surprises.