Hummingbirds are a cherished sight across North Carolina during warmer months. These tiny birds are not year-round residents, undertaking remarkable annual journeys. Their departure from the state marks a significant seasonal transition, driven by migratory instincts.
Timing of Departure
The Ruby-throated Hummingbird is the most commonly observed species in North Carolina, and its departure signals the end of the breeding season. These birds typically begin their southward migration in late August. This movement is a gradual process that unfolds over several weeks, not a sudden exodus. Males often initiate their journey first, usually about 10 to 14 days ahead of the females and juveniles.
This staggered departure continues through September, with migration peaking during this month. As October arrives, many hummingbirds from further north continue to pass through North Carolina, making it a busy corridor. While the general pattern is consistent, the exact timing can vary slightly across different regions of North Carolina, influenced by local conditions.
Factors Influencing Departure
Hummingbirds leave North Carolina primarily due to specific biological and environmental cues. A significant trigger is the decreasing duration of daylight hours, known as photoperiod. This reduction in light signals hormonal changes within the birds, prompting their bodies to prepare for migration.
While abundant food sources or warm weather might seem to suggest otherwise, these factors do not prevent their departure. Instead, an innate instinct and an internal biological clock compel them to begin their journey south. In preparation for this arduous trip, hummingbirds engage in hyperphagia, a period of intense feeding where they consume vast amounts of nectar and small insects to nearly double their body weight. This accumulated fat serves as the vital fuel reserve needed to sustain them during their long-distance flight.
Their Winter Journey
The vast majority of Ruby-throated Hummingbirds that summer in North Carolina journey to wintering grounds. These destinations are primarily in Central America and southern Mexico, extending to Panama. Some individuals also overwinter in warmer U.S. Gulf Coast regions, including parts of Florida.
A remarkable aspect of their migration is the non-stop flight across the Gulf of Mexico, a formidable 500-mile stretch. This aerial feat can demand 18 to 22 hours of continuous flight, pushing these birds to their physical limits. While many brave the direct Gulf crossing, others opt for a coastal route, following the shoreline to reach their southern habitats.
The Rare Winter Residents
While most hummingbirds depart North Carolina, a small percentage occasionally overwinter in the state. These winter residents are often not the typical summer Ruby-throated Hummingbirds, but rather western species that have veered off their usual migratory paths. Examples include Rufous Hummingbirds and Black-chinned Hummingbirds.
Some individual Ruby-throated Hummingbirds also remain, particularly in coastal areas where the moderating influence of the Gulf Stream provides milder winter conditions. The continued availability of nectar from feeders can aid their survival. Leaving feeders active through colder months offers a crucial food source for these birds.