The annual return of the Ruby-throated Hummingbird marks the arrival of the only species commonly found in New Hampshire. These diminutive birds travel thousands of miles to reach their northern breeding grounds. Their re-appearance is a moment of great excitement, signaling the warming weather and the bloom of nectar-rich flowers across the state.
The Arrival Window
The first wave of returning Ruby-throated Hummingbirds typically reaches southern New Hampshire around the last week of April. Males are the pioneers, arriving up to ten days earlier than females to establish and defend their territories. For northern parts of the state, particularly areas closer to the White Mountains, the main influx is usually delayed until the first week of May. By the middle of May, the entire state generally hosts a population of these summer residents.
Environmental Triggers
The timing of their journey north is determined by predictable environmental cues, not calendar dates. The most significant trigger is the increasing daylight hours, known as the photoperiod, which signals to the bird’s internal clock that the breeding season is approaching. Sustained warmer temperatures are also a factor, ensuring a sufficient food supply is available upon arrival. Hummingbirds rely on flower nectar and small soft-bodied insects for protein, which become active only after the last hard frost. Their migration is synchronized with the blooming of native tubular flowers, such as the Eastern red columbine, which provides their natural fuel source.
Preparing for Their Return
Homeowners should have feeders ready by early to mid-April to support returning migrants. Providing a readily available nectar source gives weary travelers the energy needed to settle into their new territories. The proper solution is a simple mixture of one part refined white sugar dissolved into four parts water.
Use only refined white sugar; never substitute honey, brown sugar, or artificial sweeteners, which can harm the birds. Red food coloring is unnecessary, as the red plastic on the feeder is enough to attract them. The mixture should be boiled briefly to dissolve the sugar, then cooled completely before being placed outside.
Feeder hygiene is paramount to the birds’ health, as fermented nectar or mold can be fatal. The sugar water should be changed and the feeder thoroughly cleaned every two to three days, or daily during periods of high heat. Placing the feeder in a shaded area helps keep the nectar fresh longer.
Departure and Migration South
The summer residency is brief, and hummingbirds begin their journey south toward their wintering grounds in late summer. Adult males are the first to depart, usually leaving around the last week of August after breeding duties are complete. Females and the young of the year linger longer to feed and build up fat reserves. Most Ruby-throated Hummingbirds have vacated New Hampshire by the end of September. Their destination requires a massive, non-stop flight across the Gulf of Mexico to wintering areas in southern Mexico and Central America.