Hummingbirds, with their shimmering colors and rapid wingbeats, are captivating visitors to Colorado. These tiny birds undertake remarkable journeys, driven by ancient migratory instincts, to reach their summer habitats each year.
Typical Arrival Windows
Hummingbirds begin arriving in Colorado from early to late spring. The earliest arrivals, primarily male Broad-tailed Hummingbirds, appear in lower elevations by late March or early April, spreading to higher mountain elevations by May. Black-chinned Hummingbirds follow, arriving mid-to-late spring, from May to mid-June. Rufous Hummingbirds, known for their fiery plumage, are seen passing through in early summer, typically July and August, though some may arrive as early as April. The Calliope Hummingbird, America’s smallest bird, is a visitor seen in July or August.
Influencing Factors for Arrival
The timing of hummingbird arrival in Colorado is linked to environmental and biological cues. Changes in daylight duration, known as photoperiod, serve as a primary trigger, signaling birds to begin northward migration from their wintering grounds. Food sources, such as nectar-producing flowers and insects, along their migratory routes and in Colorado, guide their progress. Warmer weather fronts also facilitate their movement, providing favorable conditions for their energetically demanding flight. Hummingbirds gain 25-40% body weight before embarking on long migratory flights to sustain their high metabolic rates.
Preparing for Their Visit
Residents can prepare for the arrival of hummingbirds by setting out feeders and cultivating plant life. Feeders should be placed outdoors by early to mid-April to welcome the first migrants. A simple sugar water solution, made by mixing one part table sugar with four parts water, provides essential energy; red dyes or honey should be avoided. Maintaining feeder hygiene is important, requiring cleaning every three to five days, or more frequently during warm weather, to prevent spoilage and mold growth. Planting native, nectar-rich flowers like agastache, salvia, columbine, and penstemon also offers natural food sources and enhances their habitat.
Departure and Wintering
Hummingbirds begin their southward migration from Colorado, starting in late August and continuing through early September. While most depart, some individuals may linger until October or even November. Their wintering grounds are located in Mexico and Central America. Rufous Hummingbirds travel down the Rocky Mountains during late summer and fall to wintering areas in southern Mexico. Broad-tailed Hummingbirds spend their non-breeding months in the highlands of Mexico, extending south to Guatemala, while Black-chinned Hummingbirds also migrate south in September, with some remaining in Colorado until October.