Hummingbirds are a captivating sight in Northern Illinois throughout the warmer months. As summer transitions into autumn, many people observe a decrease in hummingbird activity, leading to curiosity about when these birds depart. Understanding their seasonal movements reveals a natural phenomenon driven by instinct and environmental cues.
When Hummingbirds Depart
Ruby-throated Hummingbirds, the most common species found in Northern Illinois, begin their southward migration as early as late July or early August. Male hummingbirds are typically the first to embark on this journey, preceding females and juveniles. The main departure period for most of these birds from Illinois occurs during late August and September. While many hummingbirds will have left by mid-September, some can still be observed in the region through October, especially those originating from farther north. Departure times can vary due to age, sex, and local weather conditions.
Why They Migrate
Hummingbird migration is driven by environmental changes that signal the approach of colder months. The primary trigger for their departure is the decreasing length of daylight hours, known as photoperiod, which signals hormonal changes. As autumn progresses, temperatures cool, and the availability of their food sources—flower nectar and insects—begins to diminish. Migrating allows hummingbirds to escape the scarcity of food and harsh conditions of winter by moving to regions where resources remain abundant.
Where They Go
Hummingbirds migrating from Northern Illinois typically travel to warmer climates for the winter. The majority of Ruby-throated Hummingbirds spend their non-breeding season between southern Mexico and northern Panama. This journey often involves flying non-stop across the Gulf of Mexico, a distance of approximately 500 miles, which can take 18 to 22 hours. While most cross the open water, some may follow a longer coastal route. A small number of Ruby-throated Hummingbirds may also overwinter along the U.S. Gulf Coast or in southern Florida.
Helping Hummingbirds
Supporting hummingbirds during their migratory period is helpful, and backyard feeders can play a role. Keep feeders clean and filled with fresh nectar until at least late September or early October in Northern Illinois. This practice does not prevent hummingbirds from migrating, as their departure is primarily driven by instinct and changes in daylight, not by food availability. Maintaining feeders provides an energy source for late-season travelers and juveniles preparing for their first migration.
Alongside feeders, planting native flowers that bloom in late summer and fall provide natural nectar. Examples of plants that can provide late-season food for hummingbirds in Illinois include cardinal flower, bee balm, trumpet vine, and various salvias. These plants offer carbohydrates needed for their long journey. Ensuring a continuous supply of both natural nectar and feeder solution can assist these migrants.