Hummingbirds, with their small size, rapid wing beats, and iridescent colors, are captivating birds that frequent Kentucky gardens. These aerial acrobats are drawn to the nectar of various flowers, showcasing their unique feeding habits. As the seasons change, these tiny birds, predominantly the Ruby-throated Hummingbird, are recognized as migratory visitors rather than year-round residents of the state. They journey thousands of miles to warmer climates.
Typical Departure Timeline
Ruby-throated Hummingbirds, the most common species observed in Kentucky, begin their departure from the state in late summer and continue through early fall. The migration is not a sudden event on a single day, but rather a gradual process that unfolds over several weeks. Most of these birds will have left Kentucky by the end of August or early September. Some individuals may linger into late September, with occasional sightings even extending into early November.
The timing of departure varies among different age and sex groups. Adult male Ruby-throated Hummingbirds are among the first to initiate their southward journey. They are followed approximately two weeks later by adult females. Young birds, born during the summer breeding season, typically depart last, having spent time building up their energy reserves for the demanding flight ahead.
Environmental Factors Influencing Migration
The primary environmental cue for hummingbird migration is the decreasing number of daylight hours, known as photoperiod. This change acts as an internal clock for the birds, triggering the instinct to prepare for their long journey regardless of immediate weather conditions. It serves as a reliable indicator of the changing seasons, prompting physiological adjustments.
While photoperiod is the main driver, other environmental factors also influence the timing of their departure. Cooler temperatures, particularly overnight, contribute to the migratory urge. The diminishing availability of natural food sources, such as nectar-producing flowers and insects, further encourages their southward movement. These combined cues prompt hummingbirds to seek abundant food and warmer climates in their wintering grounds in Central America, Mexico, and the Caribbean.
Supporting Hummingbirds Before Departure
Individuals can assist hummingbirds as they prepare for their demanding migratory journey by maintaining clean and full feeders. It is advisable to keep feeders available well past the typical departure dates, often until late October or early November, to support late migrants or those passing through from more northern regions. Importantly, leaving feeders out will not prevent hummingbirds from migrating, as their departure is primarily driven by instinctual responses to shortening daylight hours. Feeders provide an energy source for these tiny birds as they build the fat reserves necessary for their extensive flights.
Supplementing feeders with late-blooming flowers can also provide valuable nectar during this period. Native plants such as blue sage, royal catchfly, asters, and goldenrods offer vital sustenance as other summer blooms fade. Other beneficial options include:
Bee balm
Cardinal flower
Trumpet creeper
Trumpet honeysuckle
Hoary skullcap
Ensuring a fresh water source is also helpful for these birds.