The Ruby-throated Hummingbird is the primary species observed in Western New York. Its annual migration is an impressive natural phenomenon, as this small creature, weighing approximately the same as a penny, undertakes a monumental journey south to its wintering grounds. This movement is a carefully timed departure orchestrated by internal signals. The travelers leave their summer territory to seek warmer climates with abundant nectar and insect sources.
Departure Timeline
The bulk of the Ruby-throated Hummingbird population begins its departure from Western New York starting in late August and continuing through mid-September. This window marks the primary southbound exodus, which is not a single, synchronized event. Adult males, having completed their reproductive duties, typically initiate the migration first, leaving their breeding territories.
Adult females and the season’s juvenile birds follow a few weeks later, ensuring the young are strong enough for the journey. While most birds will have left the region by the end of September, sightings of stragglers or late juveniles can occur well into early October.
Environmental Cues Driving Migration
The timing of this departure is not dictated by fluctuating temperatures or diminishing food supplies. Hummingbirds rely on a biological mechanism known as photoperiod, which is the amount of daylight in a 24-hour period. As the days shorten after the summer solstice, the decreasing daylight hours trigger hormonal changes within the birds.
This internal clock signals an instinctive urge to migrate, regardless of the immediate weather conditions. The physiological response to the changing photoperiod begins the preparation process. This trigger ensures the birds start their journey south with enough time to reach their wintering grounds.
The Preparation and Journey South
In the weeks leading up to migration, Ruby-throated Hummingbirds engage in hyperphagia, a period of excessive feeding. This consumption of nectar and insects is necessary to build up a substantial layer of body fat. The fat reserves are metabolized to fuel the long-distance flight, acting as the bird’s onboard energy source.
This preparation is crucial, as they may gain 25 to 40% of their body weight to complete the journey. Their final destination is typically the southern coast of Mexico and Central America, often as far south as Panama. Many migrating hummingbirds stop along the Gulf Coast of the United States to refuel before making a non-stop flight of over 500 miles across the Gulf of Mexico, a feat that can take approximately 20 hours.
Feeder Management
Understanding the light-triggered nature of migration is important for residents who maintain feeders. A common misconception is that leaving a feeder up late will delay a hummingbird’s migration, but this is untrue since departure is governed by the photoperiod, not food availability. The presence of food does not override the bird’s internal clock.
Residents should keep their sugar-water feeders clean and filled well into late September and potentially the first week of October. This practice provides a supplemental energy source for the last adults and juveniles still building up fat reserves. Continuing to offer fresh nectar supports these travelers, ensuring they have the necessary fuel for their journey south.