The Ruby-throated Hummingbird is the primary species observed throughout Arkansas during the warmer months. Their presence is temporary, as this long-distance migrant departs when the seasonal transition to fall begins. The timing of their southbound journey is a predictable event, driven by biological programming that guides them toward their wintering grounds.
Peak Departure Window in Arkansas
The hummingbird exodus from Arkansas is a gradual process. The first wave of migrants, typically adult males, begins to leave the state as early as late August. This initial movement is followed by the departure of adult females and newly fledged juvenile hummingbirds.
The peak period for southward migration occurs throughout September, when the largest numbers of birds are passing through. By the end of the third week of September, the bulk of the summer resident population has departed. Stragglers or late-season migrants from farther north are common well into October. A few individuals may even linger into early November, but the last week of September marks the end of their main season.
The Role of Photoperiod and Internal Timing
Migration is triggered not by cold weather or lack of food, but by the shortening of daylight hours. This cue, known as photoperiod, acts as the primary signal to the hummingbird’s system. As the days grow shorter after the summer solstice, the change in light exposure triggers hormonal shifts within the bird’s body.
This hormonal change activates the biological clock and initiates hyperphagia, or excessive feeding. The bird begins to consume large amounts of nectar and insects, aiming to double its body weight by accumulating fat reserves. This stored fat is an efficient fuel source, providing the energy needed for the long-distance flight ahead.
The Southern Migration Route
Arkansas hummingbirds are bound for wintering grounds across Mexico and Central America, including countries like Costa Rica, Panama, and Guatemala. The journey covers thousands of miles. Many birds fly to the Gulf Coast where they prepare for the most challenging leg of their migration.
A significant number of Ruby-throated Hummingbirds undertake a non-stop flight across the Gulf of Mexico, a distance of approximately 500 miles. This crossing can take up to 20 hours of continuous flight without stopping for rest or food. Other migrants may follow the coastline, traveling overland through Mexico to reach their final tropical destinations.
Late Season Feeder Management
A common concern is whether leaving a feeder up will prevent a healthy hummingbird from migrating, but this is a myth. Hummingbirds are genetically programmed to migrate based on the photoperiod, and a reliable food source will not override this instinct. Leaving feeders available provides an energy source for late-season stragglers or exhausted migrants passing through from northern states.
It is recommended to keep feeders clean and filled for at least two weeks after you observe the last hummingbird of the season. This ensures any final travelers have a chance to refuel before their journey south. Continue to maintain the feeders until freezing temperatures become consistent, as even a rare species may benefit from the supplemental nectar.