Hummingbirds are a captivating presence in Tennessee during warmer months, bringing bursts of color and energetic aerial displays. The Ruby-throated hummingbird, the sole species that breeds in the state, enriches the local ecosystem throughout spring and summer. As seasons shift, these tiny birds embark on an annual journey, migrating thousands of miles to warmer climates. Understanding their departure offers insight into the natural world and the adaptations allowing these small creatures to undertake such a journey.
Typical Departure Timing
Hummingbirds in Tennessee typically begin southward migration as summer transitions into fall. The first to depart are often the adult males, starting their journey as early as July or August, soon after the breeding season concludes. Females and the young birds hatched during the summer follow later, usually from late August through September. Most Ruby-throated hummingbirds will have left Tennessee by early to mid-September, with most gone by month’s end. A few stragglers may still be observed passing through Tennessee into October, particularly those migrating from northern regions.
Key Migration Triggers
The departure of hummingbirds from Tennessee is not simply a reaction to the onset of cold weather, but rather an instinctual response to several environmental cues. A primary trigger for their migration is the decreasing duration of daylight hours, known as photoperiodism, which signals hormonal changes in their bodies. This prompts them to accumulate fat reserves, sometimes doubling their body weight, to fuel the journey. Declining temperatures and the diminishing availability of natural food sources, such as nectar from flowers and insects, also contribute to this migratory urge.
Their Winter Destinations
Hummingbirds migrating from Tennessee undertake a journey to their wintering grounds, primarily located in southern Mexico and Central America. Most Ruby-throated hummingbirds spend the colder months in these tropical regions, with some traveling as far south as Panama. This migration often involves a non-stop flight across the Gulf of Mexico, a distance of approximately 500 miles, which can take 18 to 20 hours. While most opt for this overwater route, some may follow an overland path along the Texas and Mexican coasts.
Supporting Hummingbirds Before Migration
Residents can support hummingbirds in Tennessee as they prepare for their migration. Maintaining clean hummingbird feeders filled with a solution of one part white granulated sugar to four parts water provides a supplementary energy source. It is helpful to keep these feeders up even after the peak departure period, as late-migrating individuals can benefit from available food. Planting late-blooming, nectar-rich flowers such as salvias, cardinal flowers, butterfly weed, lantana, and marigolds offers natural foraging opportunities. Avoiding the use of broad-spectrum pesticides also ensures a healthy supply of insects, an important part of a hummingbird’s diet.