Hummingbirds are a cherished sight across Colorado. These tiny, energetic birds are not permanent residents, as their presence in the state is part of an impressive annual migratory cycle. As seasons change, these aerial acrobats embark on long journeys.
Typical Departure Schedule
Hummingbirds generally begin their departure from Colorado in late summer, with migration peaking through August and September. Most have moved south by early fall, though some may linger into October or November. The exact timing varies by species; for instance, Black-chinned Hummingbirds typically begin their southward journey around early September.
Rufous Hummingbirds often pass through Colorado in late August or September on their way to wintering grounds. Calliope Hummingbirds are also seen migrating through Colorado, usually departing by October. Broad-tailed Hummingbirds tend to remain in the state longer than other species, with some individuals staying as late as November. Male hummingbirds often initiate their migration a few days earlier than females and juveniles.
Factors Influencing Departure
The primary signal triggering hummingbird migration is the changing length of daylight hours, known as photoperiod. As days shorten in late summer and early fall, this cue prompts a physiological response, preparing them for their long journey. This innate predisposition drives them to migrate, regardless of local weather conditions or food abundance.
While photoperiod is the main driver, other factors like nectar and insect availability also reinforce the migratory instinct. As natural food sources diminish, the birds’ need for consistent energy reserves becomes more pronounced. Regional weather patterns can influence departure timing, but are not the fundamental trigger for migration itself.
The Migration Journey
After leaving Colorado, most hummingbirds embark on journeys to their wintering grounds, primarily in Mexico and Central America. They travel thousands of miles, often alone. Their journey presents numerous challenges, including weather, predators, and the constant need for food sources.
To prepare for this demanding travel, hummingbirds engage in hyperphagia, feeding intensely to build fat reserves. They consume large amounts of nectar and insects, accumulating fuel for their long flights. These fat stores provide the energy for sustained flight, allowing them to cover significant distances during migration.
Supporting Hummingbirds Before They Leave
Support hummingbirds before their departure by ensuring feeders remain clean and filled with fresh nectar solution. Continue offering nectar into the fall; do not remove feeders too early. Leaving feeders available does not prevent migration, as their departure is driven by instinct and changing daylight, not food scarcity. Feeders provide a valuable supplemental energy source, helping birds build fat reserves for their long flights.
A solution of four parts water to one part white sugar is suitable for feeders; avoid red dye as it can be harmful. Regularly cleaning feeders and changing nectar, especially in warmer weather, maintains a healthy feeding environment. Planting native, nectar-rich flowers that bloom in late summer and fall also offers natural food sources.