The presence of hummingbirds in Ohio is a temporary summer phenomenon, driven by the need to migrate between breeding grounds and wintering habitats. The species most commonly observed is the Ruby-throated Hummingbird (Archilochus colubris), which travels thousands of miles each year. Their seasonal appearance is governed by a biological clock that signals when it is time to depart for their wintering grounds in Mexico and Central America.
The Critical Migration Window
The departure of Ruby-throated Hummingbirds from Ohio is not a single, synchronized event but rather a gradual process that spans several weeks in late summer and early fall. The main pulse of migration begins in late August, though the heaviest movement typically occurs throughout September. This timing is dependent on latitude, with birds in northern Ohio starting their journey slightly earlier than those in the southern regions.
Adult males are the first to vacate the area, often leaving their breeding territories by mid-to-late August. The adult females and the young of the year follow a few weeks later, comprising the bulk of the birds seen during the peak of the southward movement. While most of the local population has departed by the end of September, sightings of stragglers and transient birds from farther north can continue into the first two weeks of October. These late-season travelers are often young birds completing their first migration.
Environmental Cues for Departure
Hummingbirds initiate their journey south not because of dropping temperatures or a lack of flowers, but in response to the changing duration of daylight. This biological trigger is known as photoperiod, the shortening of the light period each day that signals preparation for migration. This innate response overrides external factors like weather or the immediate availability of food sources.
Preparing for a 2,000-mile journey, which includes a non-stop flight across the Gulf of Mexico, requires energy build-up. Hummingbirds enter a state of increased feeding known as hyperphagia, where they dramatically increase their food consumption to accumulate fat reserves. They can gain as much as 10% of their body weight per day during this period, storing fat that will serve as the primary fuel for their flight.
This accumulated fat is metabolized efficiently, allowing the birds to sustain the high-energy demands of long-distance migration. The physical transformation is observable, with pre-migratory birds appearing noticeably plumper as they maximize their energy stores.
Common Misconceptions About Feeding
A widespread concern among backyard bird enthusiasts is the misconception that keeping nectar feeders full will prevent hummingbirds from migrating. This idea is incorrect because the birds are compelled to leave by their internal clock, which is set by the shortening days. Removing feeders prematurely can do more harm than good by eliminating a valuable energy source for the journey.
Feeders become important in early fall, serving as refueling stations for both the local juveniles preparing to leave and the birds passing through from Canada and the northern United States. It is beneficial to maintain clean, fresh feeders well past the main departure window. A practical guideline is to keep feeders available until at least the middle of October, or until no hummingbird has been sighted for a continuous period of two weeks.
This extended presence ensures that any late-migrating individuals have access to the high-calorie sugar water they need. The few birds that remain very late into the season are typically stragglers, sometimes young or injured birds, and the continued availability of nectar supports their survival. Once all activity has ceased, the feeders can be taken down for the winter.