Note To Our Readers

The Grand Passage

Each year, beginning in late summer, an extraordinary natural event begins—migration. Migration is the journey from a breeding site to where a bird spends the rest of the year. This “miracle of flight” is part of the annual cycle of life. Hundreds of millions of birds migrate through Missouri between late summer and winter.

Birds migrate using four primary types of “compasses” to navigate: the sun, the stars, the earth’s magnetic field and visual landmarks. Temperature and day length play a role in movement timing or when the birds move from specific locations throughout their migration.

Many Missouri birds are short distance migrants spending the winter in Arkansas or Texas, though about a third of our breeding bird species fly long distances outside of the United States, where food and shelter help them survive the winter. Stopover or staging areas allow birds to find food, build body fat and rest for their annual migrations. Birds remain at these staging areas based on weather, food availability, how much fat they have stored and day length.

In the waning days of summer, watch first for shorebirds, warblers, teal and monarch butterflies. During crisp fall days, look for kettles of hawks spiraling south. On clear November nights, listen for the chorus of snow geese journeying south. Migration’s end is signaled by the arrival of bald eagles and other hearty species such as goldeneyes and common mergansers.

Fast migration facts: Ruby-throated hummingbirds weigh about 4.8 grams and can store enough fat to fly nonstop over a 600-mile stretch of open ocean from the Gulf Coast to the Yucatan Peninsula in Mexico, or vice versa in the spring. Hawks and other large soaring birds migrate overland, not over water. Along the eastern coastal lowlands of Mexico, huge concentrations soar on rising warm air pockets—observers can watch several hundred to thousands of migrating birds on a good day.

A large, spectacular migratory event is called a “Grand Passage” and may occur either in the fall or the spring migration. In November 1995, 90,000,000 waterfowl flew south in front of an extreme cold front. Their migratory movement created a Grand Passage where the flocks of birds were so dense that Midwest airport radars couldn’t distinguish between birds and airplanes. Another example of a Grand Passage is the mass arrival of trans-Gulf migrants in Texas and Louisiana after their 600-mile flight across the Gulf of Mexico.

Other animal groups migrate south for winter, including bats, dragonflies and butterflies. From early to mid-September, watch for migrating monarch butterflies. You can often observe hundreds of monarchs a day. They migrate approximately 3,000 miles to central Mexico, making them the only butterfly to make such a long, two-way migration every year. However, it’s their children and grandchildren that complete the migration during the next year.

To protect and conserve all these species of birds and the monarch butterfly, habitat must be protected in the United States, Canada, Mexico, Central America and South America. Without breeding ground habitat, wintering ground habitat, quality staging or stopover habitat and the interconnectedness of all these locations, North America’s migration would slowly decline and possibly cease to exist.

Get involved! Today’s technology allows citizens to provide information on migration dates and individual species locations. Universities and organizations offer websites for anyone to log their migration observations. Some websites allow the user to track migration patterns, and there are smart phone applications on real-time migration mapping. This is a great opportunity to both contribute to scientific studies and get outdoors with family and friends. Seeking out and recording these fascinating natural events is a fun, easy and accessible way to introduce people of all ages and abilities to the outdoors. It’s a natural way to help create conservationists and preserve our outdoor heritage.

Take the time to enjoy the fall migration and introduce others to this wonder of nature. Observe monarch butterflies, look for shorebirds, pursue waterfowl or explore for eagles. You might be lucky and experience one of Missouri’s Grand Passages—and even if you don’t, you will certainly witness one of our most spectacular natural events.

Tim Ripperger, deputy director