Hummingbirds are a beloved part of the Colorado landscape, adding beauty and wonder to backyards and gardens during the warmer months. However, as fall approaches and temperatures begin to drop, hummingbirds depart Colorado for their winter migratory grounds farther south. Determining exactly when these tiny birds leave Colorado each year depends on a few key factors.
Hummingbird Migration Patterns
There are three species of hummingbirds commonly found in Colorado during the summer breeding season:
– Broad-tailed Hummingbird
– Rufous Hummingbird
– Calliope Hummingbird
All three species breed in Colorado between May and July before beginning their southerly migrations in late summer or early fall. The timing of their migrations depends somewhat on the species:
| Species | Migration Period |
|---|---|
| Broad-tailed Hummingbird | Mid-July to mid-September |
| Rufous Hummingbird | Mid-August to early October |
| Calliope Hummingbird | Mid-August to late September |
As this table shows, Rufous Hummingbirds tend to depart a bit later in the fall than Broad-tailed and Calliope Hummingbirds. However, there is some overlap between the migration periods of the different species.
Fall Weather Patterns
The exact timing of hummingbird migration each fall also depends heavily on weather conditions. Colder temperatures and fewer daylight hours serve as triggers for the birds to begin their southern journeys. However, if late summer and early fall bring warmer weather to Colorado, the hummingbirds may linger longer before migrating.
For example, during an unseasonably warm fall, Rufous and Calliope Hummingbirds may still be spotted at Colorado feeders in early October. But if a cold snap hits in September, the birds will likely depart quicker for their wintering grounds in Mexico and Central America.
Availability of Food Sources
Access to adequate food sources is another factor impacting when hummingbirds leave Colorado each fall. Abundant late-blooming flowers and active feeders provide energy for the birds as they prepare for migration. However, once flowers fade and freezing overnight temperatures set in, food becomes more scarce. This lack of food availability further triggers the hummingbirds’ migration south.
Home gardeners who want to provide food as long as possible can keep feeders up through September and early October. Just be sure to bring feeders inside overnight once freezing temperatures arrive so the sugar water does not freeze and damage the feeder.
What Month Do Most Hummingbirds Leave Colorado?
Based on typical hummingbird behavior and migration patterns, most hummingbirds leave Colorado by early October, with the end of September being more common.
Here is an overview of the expected migration timeline for each species:
Broad-tailed Hummingbird
Broad-tailed hummingbirds begin migrating south out of Colorado in mid-July, with peak migration occurring in August and early September. By late September, the vast majority have departed Colorado. Just a few stragglers may linger into the first week or two of October if food resources and warm weather allow.
Rufous Hummingbird
Rufous hummingbirds nest the latest in Colorado, with most adults and juveniles leaving the state between mid-August and early October. Late September is the peak departure time, though individuals have been spotted as late as mid-October during unseasonably warm falls. By late October, nearly all Rufous Hummingbirds have left Colorado.
Calliope Hummingbird
Calliope hummingbirds follow a similar migration timeline to Broad-tailed Hummingbirds. Most depart Colorado between mid-August and late September, with peak migration in early September. Only a handful of stragglers may continue to be seen during the first few weeks of October if weather and food sources permit. But by October 15th, Calliope Hummingbirds are essentially gone from the state for the winter.
Earliest and Latest Departure Dates
Based on average migration patterns and recorded observations, here are the typical earliest and latest departure dates for hummingbirds leaving Colorado:
| Species | Earliest Departure | Latest Departure |
|---|---|---|
| Broad-tailed Hummingbird | Mid-July | Early October |
| Rufous Hummingbird | Mid-August | Mid-October |
| Calliope Hummingbird | Mid-August | Mid-October |
So while a smattering of hummingbirds may on rare occasions linger into mid-October, the vast majority have left Colorado for warmer climates by early October or late September.
How to Attract Hummingbirds into Fall
Even though most hummingbirds leave Colorado by early October, you may be able to prolong their stay and enjoyment by providing a welcoming habitat into the fall. Here are some tips:
Keep Feeders Clean and Filled
It is essential to maintain fresh nectar in clean feeders as long as possible into fall. Change the nectar every few days to prevent spoilage, and take feeders apart weekly for a thorough cleaning. This will help ensure sick birds do not spread diseases at crowded feeders as they fuel up for migration.
Provide Shelter from Cold
Hummingbirds burn energy incredibly fast to power their rapid metabolism and need to escape freezing temperatures. Having feeders in a sheltered spot blocked from wind and cold will help extend their stay. You can also provide extra roosting spots with native plants or roost boxes specifically for hummingbirds.
Choose Late-Blooming Flowers
Planting native flowers and shrubs that bloom into fall provides natural food sources. Good options include sage, fireweed, cardinal flower, trumpet vine, and autumn-blooming salvias. Avoid removing spent flowers so hummingbirds can still access the small insects attracted to the plant.
Use Sugar Water, Not Honey
While honey seems like a natural nectar, it can promote dangerous fungal growth in feeders. Stick to mixing 4 parts water to 1 part white refined sugar and boiling for optimal nectar. Never use artificial sweeteners, honey, or brown sugar.
Avoid Pesticides
Hummingbirds rely heavily on tiny insects for food, so avoid spraying pesticides that could eliminate these food sources and inadvertently poison birds.
Don’t Prune Too Early
It’s tempting to cut back gardens and plants as they fade in fall, but leave as much vegetation intact as possible so hummingbirds still have places to shelter and forage.
Enjoy the Fall Colors as HummersDepart
While saying goodbye to hummingbirds can be bittersweet, their departure signals the start of a colorful new season in Colorado. As the hummingbirds leave in September and October, the aspens and other deciduous trees put on their own migration spectacle as green leaves turn to shimmering gold.
Take time to enjoy the fall foliage display as the mountains come ablaze with color. And know that next spring, the hummingbirds will return once again to delight us with their beauty and antics. Though they leave in fall, they are never gone for long from the Colorado landscapes they call home each summer.
Conclusion
Most hummingbirds leave Colorado by early October, with late September being the peak departure period for most species. Broad-tailed Hummingbirds begin migrating south in mid-July, followed by Rufous and Calliope Hummingbirds in mid to late August. While a few stragglers may linger into mid-October if conditions allow, providing clean feeders, shelter, and late-blooming flowers can help extend the hummingbird season into the fall. No matter when they depart, enjoying the fall foliage display helps highlight the natural rhythms that make Colorado so beautiful to both residents and migrating birds.
