The hummingbird operates on a constant energy budget. These tiny birds possess the highest mass-specific metabolic rate of any warm-blooded animal, requiring them to consume roughly one and a half to three times their body weight in nectar and insects daily. This intense biology means that timing—specifically, when they “come out” each year and each day—is central to their survival.
Seasonal Arrival and Departure
The annual appearance of hummingbirds is dictated by the energy demands of their long-distance migration. For most North American species, such as the Ruby-throated Hummingbird, the northward spring migration begins as early as late February. Birds follow warmer weather and blooming flowers, guided by internal cues like changing daylight length and temperature fluctuations. Males are typically the earliest arrivals, reaching breeding grounds about a week before the females.
To support these early travelers, experts recommend placing feeders out one to two weeks before the historical first arrival date. For Gulf Coast states, this means feeders are ready in late February, while northern states may not see arrivals until late April or May.
The fall departure is triggered by the shortening day length, causing the birds to accumulate body fat for the journey south. Leaving feeders up long after the majority of birds have departed is recommended to ensure late-migrating individuals or rare vagrants have a chance to refuel. Feeders should remain accessible until at least mid-October, or until two weeks after the last sighting.
Regional Differences in Migration Timing
The timing of when hummingbirds appear and disappear varies significantly across the continent, depending on the species and its migratory habits. In the eastern two-thirds of the United States, the Ruby-throated Hummingbird is the single common species. It is a strict neotropical migrant that winters in Central America, resulting in a predictable seasonal window from late March or April to September.
In contrast, many western species exhibit varied, less structured patterns that include year-round residency. The Anna’s Hummingbird, for instance, is a common resident along the Pacific coast. This year-round presence is possible because these species are hardier and can sustain themselves with insects and feeders during mild winters. For many western residents, hummingbirds are constantly “out,” shifting their activity only in elevation rather than latitude.
Daily Activity Patterns and Torpor
Hummingbirds have a daily rhythm that dictates when they are actively searching for food. Their highest energy expenditure occurs during the morning hours, making them most active at dawn to replenish calories burned overnight. They must continue to feed frequently throughout the day to sustain their hovering flight and extremely high body temperature, which is normally around 100 degrees Fahrenheit.
As night approaches, these tiny birds employ a survival strategy called torpor to avoid starving while they rest. Torpor is a state similar to hibernation, where the bird substantially lowers its metabolic rate, sometimes by as much as 95%. During this time, their heart rate and breathing slow dramatically, and their body temperature can drop by 50 degrees Fahrenheit, allowing them to conserve energy when they cannot forage.
Waking up from this deep, near-shutdown state is an energetic process that can take up to an hour. The bird must shiver its flight muscles to generate the heat needed to raise its core temperature back to normal. This daily cycle means that “coming out” each morning is a calculated biological event necessary for survival. The need to quickly break torpor is why their first feeding activity at sunrise is so intense.