Fall Migration

As the sun rises each morning on us Hoosiers, turning the sky into a palette of beautiful colors, many of us are greeted with a song. Even as the temperature drops, the birds sing still—their notes penetrating the morning silence like the pluck of a harp. However, it is not the same mysterious singer who plays the part of our alarm each morning. Why? Indiana is home to more than 400 species of birds, many of which migrate as temperatures drop. The state also provides important stopover habitat for birds traveling south from northern regions. Thus, our morning choir changes members with the seasons.

This time of year is known to birders as Fall Migration. The sky acts as a sort of avian highway. Most migratory birds have evolved to fly at night, proving to be beneficial to the survival of their species, as they can better avoid daytime predators, take advantage of calmer skies, and stay cool under the moonlight. Fall Migration begins in August with the flight of the state’s shorebirds, who call the Lake Michigan shoreline and inland wetlands their home. As September approaches, migration quickens with the addition of nocturnal songbirds such as warblers, thrushes, and flycatchers. By early October, sparrows, blackbirds, and other late-season migrants begin heading south with the cooler weather, marking one of the final waves of migration before winter. The shape of migration shifts again in November. The summer songbirds have mostly passed through; now it is time for the raptors, cranes, and waterfowl to ride cold fronts south. Unlike our songbirds, these species won’t fuel up on their journey by stopping to snack at backyard feeders. Instead, they gather at shorelines, protected wetlands, and inland lakes and ponds.

Why Do Birds Migrate?

As temperatures drop and daylight hours grow shorter, many birds begin migrating south from Indiana. The shorter amount of daylight acts as a biological cue, signaling that it is time to begin their journey. This happens for a very simple reason: as winter approaches, insects, nectar, fresh food sources, and open water become scarce. Thus, birds migrate to milder climates where food and other resources are more readily available.

For many of our songbirds, this includes parts of the southern United States, Central and South America, where insects and fruits remain plentiful. Raptors follow the coastlines down to Mexico and Central America. Many waterfowl and cranes settle in southern wetlands and coastal marshes, where they can find abundant food and open water throughout the winter.

Now you may be wondering about Indiana’s resident singers: the birds who don’t migrate in the winter. These birds’ food supply doesn’t diminish with changing weather. Cardinals and sparrows, for example, can rely on seeds that remain available throughout the winter, with bird feeders providing an additional food source during cold spells. Chickadees, on the other hand, spend the autumn caching nuts and insects in hidden spots to help them survive the winter. Woodpeckers similarly search for insects hidden beneath tree bark while also turning to seeds and nuts when necessary, including sunflower seeds and suet for high-fat energy.

Rest Stops Matter

For those that make the far journey south, rest stops are a critical aspect of successful migration. Because these long flights take an incredible amount of energy, birds use stopover sites to sleep and refuel. A good stopover site provides birds with cover and protection from predators while they rest, along with calorie-rich foods like insects, seeds, and nectar that help them build up fat reserves for the next day of travel.

Examples of these sites include the Indiana Dunes National Park and State Park, Eagle Creek Park, and the Jasper-Pulaski Fish and Wildlife Area. Southbound birds follow the shoreline of Lake Michigan, stopping along oak savannas, ancient dunes, prairies, and marshes that provide abundant food and shelter for a variety of species. Parks such as Eagle Creek provide acres of deciduous woods, ponds, mudflats, and grasslands that offer valuable habitat for both resident and migrating birds. The marshes of the Jasper-Pulaski Fish and Wildlife Area serve as an important stopover site for sandhill cranes in late fall; thousands of cranes pause here to rest and refuel before continuing their journey south.

The availability of thriving stopover sites is an essential requirement for migrating birds. Just as a person on a cross-country road trip needs to stop along the way as they cross state lines, birds need access to the food and habitat they rely on to rest and refuel during migration.

What You Can Do To Help

There are several simple things you can do to support these magnificent little singers during Fall Migration, whether they are passing through Indiana or staying here for the winter.

• Fill your bird feeder with high-fat, calorie-dense, clean ingredients

• • • Examples include black oil sunflower seeds, suet cakes, unsalted peanut halves, thistle seed
    • Avoid cheap fillers common in many bulk seed mixes

• Keep fresh water in bird baths

• • • Provides hydration to migrating birds, even those that don’t typically seek out backyard feeders
    • Clean water is important for birds to preen and maintain their feathers
    • Empty and refill bird baths regularly to prevent stagnant water, algae buildup, and mosquitoes
    •  Keep the water shallow—no more than two inches deep—and consider adding pebbles or stones to give birds a secure place to stand

• Turn off unnecessary exterior lighting

• • Bright artificial lights, especially in urban areas, can cause birds to collide with buildings or windows, or become confused and disoriented on their flight path
  • Turning off outdoor lighting between 11 PM and 6 AM during the months of Fall Migration helps birds navigate more safely
  • Opt for more wildlife-friendly lighting: swap bright white LEDs for warmer bulbs—amber, orange, or red LEDs; shielded fixtures, which funnel light downwards and away from the night sky

by Alison Isbell

Public Relations and Communications Intern at IWF