Hummingbird migration is one of the most highly anticipated bird migrations in North America, but when do hummingbirds migrate? Knowing when these small birds make their seasonal movements can help backyard birders be prepared to welcome them to and from their yards.
About Hummingbird Migration
Even though hummingbirds are the smallest birds in the world, their migrations can span hundreds or thousands of miles. While there are more than 300 hummingbird species, only a handful of them regularly migrate. Most of the hummingbirds of North America do migrate seasonally between northern breeding grounds and southern wintering grounds. Unlike many birds, however, hummingbirds migrate individually and do not travel in seasonal flocks.
Backyard birders who have fed hummingbirds for years quickly learn that these flying jewels can be very predictable with their migration patterns. Individual birds often migrate at the same time each year, even arriving and leaving the same yards within just a day or two. But how do they know when it is time to migrate?
When Hummingbirds Migrate
Several factors affect hummingbird migration and when exactly these small birds set forth on their long journeys. The most important factor that determines the timing of hummingbird migration is daylight: the amount of daylight and the angle of the sun relative to the location. As the light levels change seasonally, hummingbirds will purposefully eat more to gain weight that will be valuable energy for their upcoming long flight.
Other factors that influence when hummingbirds migrate include:
- Food: Hummingbirds will move along their migration journeys as food sources appear and disappear. The most important food source is nectar-producing flowers, but the availability of insects is also a factor.
- Weather: Local storms and strong winds can impact hummingbird migration to a minor degree, delaying the birds' journeys by a day or two.
- Age: Mature birds often start their migration earlier than juvenile birds. Younger birds take longer to build up their new strength and maturity before setting forth on the long migration journey.
- Gender: In some hummingbird species, such as the ruby-throated hummingbird, males migrate a few days before females. This gives the male birds time to establish territories so they can successfully court arriving females at the beginning of the breeding season. They follow the same pattern for fall migration to establish winter territories.
- Distance: The further hummingbirds have to migrate, the sooner they start their journey. The rufous hummingbird, for example, has the longest migration of any hummingbird species – traveling between Mexico and Alaska – and may begin migrating long before other species are traveling.
In spring, hummingbirds may begin flying north as early as January, taking several months to travel to their breeding grounds and arriving by mid-May at the northernmost parts of their range. In the fall, some species begin migration as early as July, though most hummingbirds don't begin their southward movements until late August or mid-September.
Helping Migrating Hummingbirds
Backyard birders can take several steps to help migrating hummingbirds. It is one of the most common bird feeding myths that feeding hummingbirds will prevent them from migrating – in fact, savvy birders put their hummingbird feeders up early in the spring and keep them up late in the fall so the birds have a ready food source no matter how local flowers are blooming. Other ways to help migrating hummingbirds include:
- Planting flowers to attract hummingbirds with a natural food source, including both early and late blooming flowers for ample nectar in the spring and fall.
- Providing nesting materials during spring migration for breeding hummingbirds to quickly and easily build nests to raise their young.
- Taking steps to keep hummingbird nectar from freezing in the late fall so it is still available to late-migrating hummingbirds.
- Support conservation initiatives and habitat preservation in hummingbirds' winter grounds so they will have safe territories on both ends of migration.
Knowing when hummingbirds migrate gives birders a migration timeline to anticipate when they will see these beautiful birds, and taking steps to help them will ensure successful migrations for generations of hummingbirds to come.
Photo – Ruby-Throated Hummingbird © thefixer