Hummingbirds, with their iridescent plumage and rapid wing beats, are tiny birds known for their ability to hover mid-air. They undertake annual migrations, a testament to their endurance and a key part of their life cycle.
Triggers for Migration
Hummingbird migration is primarily initiated by environmental cues, not cold weather. A significant trigger is the gradual decrease in daylight hours as summer transitions to fall, signaling it is time to begin their southward journey. The reduction in food availability also influences their departure, as nectar-producing flowers fade and insect populations decline. An innate biological clock also guides their instinct to migrate. Most hummingbirds start their journey south in late summer to early fall, typically from August through October.
Preparing for the Journey
Before migration, hummingbirds undergo significant physiological and behavioral changes. They enter hyperphagia, consuming large amounts of food to build fat reserves. This allows them to gain substantial weight, often increasing their body mass by 25-40%. This stored fat provides the energy needed for their long flights. Some species also undergo a pre-migratory molt, replacing worn feathers for optimal flight efficiency. Though generally solitary, they might gather at abundant food sources before departure.
Wintering Grounds
Most North American hummingbirds spend winter in warmer southern climates. Their primary destinations include Mexico, Central America, and parts of the Caribbean. This migration allows them to find ample food sources like flowers and insects throughout the colder seasons. For instance, the Ruby-throated Hummingbird, a common species east of the Mississippi River, largely migrates to southern Mexico and Central America, extending as far south as Panama. Western species, such as the Rufous Hummingbird, travel to Mexico, particularly to wooded areas in states like Guerrero. These wintering grounds typically offer tropical forests, coastal areas, or other habitats with a consistent supply of nectar and insects.
Helping Migrating Hummingbirds
To support migrating hummingbirds, maintain clean and full feeders, especially during late summer and fall. This practice does not prevent them from migrating, as their departure is driven by environmental cues, not a lack of food. Feeders provide an energy source as they prepare for their long journeys. Planting native flowers that bloom in late summer and fall also provides natural nectar sources, such as Cardinal Flowers, Salvia, Columbines, and Bee Balm. Ensure shallow water sources are available for bathing and drinking. Avoid using pesticides, especially neonicotinoids, which can harm hummingbirds by affecting their metabolism and reducing their insect food sources.