Hummingbirds are a cherished sight across Colorado during its warmer months, captivating observers with their rapid wingbeats and shimmering plumage. These small, energetic birds bring vibrant activity to gardens and natural landscapes, marking a natural cycle of appearance and disappearance throughout the year.
When Hummingbirds Depart Colorado
Hummingbird departure from Colorado is a gradual process spanning several weeks, typically beginning in late summer and extending into early fall. Most hummingbirds leave from late August through September, with some individuals and species lingering into October or even early November. Environmental cues play a significant role in triggering this migratory instinct. Shortening daylight hours, declining temperatures, and a reduction in natural food sources like nectar and insects signal to the birds that it is time to begin their southward journey.
Different hummingbird species found in Colorado may exhibit slightly varied departure timings. For example, Rufous hummingbirds are often among the earliest to begin their migration, sometimes passing through Colorado as early as late June through September on their way south. Conversely, Broad-tailed hummingbirds, which are common breeders in Colorado, tend to remain longer and may depart as late as mid-October. Black-chinned hummingbirds typically leave around the first week of October, while Calliope hummingbirds may pass through until the third week of September or into October.
The Journey South: Why and Where
Hummingbirds undertake their journey south due to a biological imperative driven by the changing seasons. Their migration is primarily a survival strategy, allowing them to escape the colder winter temperatures in Colorado where food sources become scarce. They seek warmer climates where nectar-producing flowers and insects remain abundant year-round, ensuring a continuous food supply.
Most hummingbirds that breed in Colorado travel to wintering grounds primarily in Mexico and parts of Central America. Species like the Broad-tailed hummingbird migrate to the highlands of Mexico south to Guatemala, while Black-chinned hummingbirds typically head to western Mexico. Rufous hummingbirds, known for their extensive migratory routes, often follow the Rocky Mountains south to Mexico after breeding further north. These incredible distances are covered by birds weighing less than a penny, who prepare for their journey by consuming large amounts of nectar and insects to build up fat reserves, sometimes increasing their body weight by 25-40%.
Supporting Hummingbirds Before and During Migration
Supporting hummingbirds involves ensuring reliable food sources as they prepare for migration. Keep feeders clean and filled with fresh nectar (a solution of one part table sugar to four parts water) throughout late summer and fall. This practice provides supplemental energy for resident birds building reserves and for those passing through on their migratory routes. Clean feeders regularly, ideally every few days, to prevent the growth of mold and bacteria, which can be harmful to birds.
Planting native, late-blooming, nectar-rich flowers offers a natural and continuous food supply for hummingbirds. These plants provide essential nutrients that feeders alone cannot. A common misconception is that leaving feeders out too long will prevent hummingbirds from migrating; however, their migration is governed by instinct and environmental cues like changes in daylight, not by the availability of feeders. For feeder safety, avoid adding red dye to nectar, as it is unnecessary and potentially harmful to the birds.