Orioles are migratory birds that bring color and song to Illinois each year. Their return is a welcome sign of spring, marking an annual cycle where they journey north from warmer climates to Illinois for the breeding season.
Spring Arrival and Migration Patterns
The arrival of orioles in Illinois marks a significant phase in their annual migration. Two common species observed are the Baltimore Oriole and the Orchard Oriole. Baltimore Orioles typically arrive in Illinois in late April and early May, with peak migration from mid-April to mid-May. Orchard Orioles follow a similar, slightly later schedule, starting to arrive in late April. These birds undertake long journeys from their wintering grounds, extending from the southern United States through Central America and northern South America.
Their northward migration is prompted by environmental cues, increasing daylight hours and rising temperatures. These factors signal that northern breeding grounds are becoming suitable for nesting and raising young. Many orioles seen in Illinois during spring migration are passing through to more northern breeding territories. However, a substantial number remain in Illinois to nest, especially in areas with suitable habitat like woodlands, forest edges, and areas near waterways.
Summer Stay and Autumn Departure
Once orioles arrive in Illinois, they begin nesting and breeding. Baltimore Orioles typically nest in May and June, with females building intricate, woven, hanging pouch nests in deciduous trees such as elm, willow, apple, cottonwood, and maple. Orchard Orioles also build cup-like nests, often in apple or willow trees, and lay eggs in June.
During the summer, their diet shifts to accommodate their growing young. While they enjoy sugary foods like nectar and fruit in spring, orioles consume more insects, such as caterpillars and spiders, during the nesting season. This protein-rich diet provides essential nutrients for their offspring.
As summer ends, orioles prepare for their southward migration. Fall migration for Baltimore Orioles can begin as early as July, with most departing in August. By early September, it becomes uncommon to see orioles in Illinois. Orchard Orioles also begin their fall migration early, with some starting to head south by late July and continuing through September. This departure is driven by the decreasing availability of food sources and the onset of cooler weather.
Welcoming Orioles to Your Yard
Attracting orioles to a backyard involves providing specific food sources and suitable habitat. Orioles prefer sweet, high-energy foods, especially during their spring and fall migrations. Offering orange halves, grape jelly, and sugar water (nectar) is effective. Orange halves can be placed on feeder spikes or in shallow dishes, and grape jelly is offered in small, accessible containers. Oriole nectar feeders, often orange-colored, provide a sugar-water solution similar to hummingbird nectar.
Set up feeders early, ideally in late March or early April, before their typical arrival time. This ensures food is available when migrants arrive, increasing the likelihood they will utilize the feeders. A clean, shallow water source, such as a birdbath, also attracts orioles, particularly if it has a bubbler or dripper to create moving water. Additionally, planting native deciduous trees like maples, elms, and oaks, along with flowering shrubs, offers both shelter and potential nesting sites.