Many small songbirds migrate at night, when temperatures are cooler and there are fewer predators.
Millions of birds are expected to pass over Green Country in the coming weeks as fall migration reaches one of its busiest periods.
Tim O’Connell, an associate professor in Oklahoma State University’s Department of Natural Resource Ecology and Management, said birds have been moving south since mid-July. But September brings some of the largest waves of the season.
Many small songbirds migrate at night, when temperatures are cooler and there are fewer predators. O’Connell said the birds rely on shortening daylight hours—not temperature—to signal when it is time to begin the journey south.
“As those days start to get shorter, that triggers these hormonal changes in their bodies to begin to prepare them for migration,” O’Connell said. “It doesn’t matter if it’s hot or cold or dry or wet in August and September, they’re moving.”
Weather radar can help track those nighttime movements. O’Connell said radar data has shown nights when millions of birds moved through Oklahoma.
He expects another major wave around mid-September, followed by a second wave of different species around mid-October.
As the birds move through the region, O’Connell said homeowners and businesses can help reduce a major threat: window collisions.
Birds do not recognize glass as a solid barrier, and bright outdoor lighting can disorient nighttime migrants and draw them toward buildings with large glass windows. O’Connell said window strikes kill an estimated billion birds in the United States each year.
“The more we can figure out or get people to voluntarily turn off those lights, especially at the peak times when birds are migrating, the fewer birds should end up in the position where they can smack into a window and hurt themselves,” O’Connell said.
He recommends turning off unnecessary outdoor lights, directing needed lights downward and using softer amber or yellow-orange lighting instead of bright white LEDs when possible.
O’Connell said reducing unnecessary lighting can help birds navigate safely—and may also help lower energy costs.
To learn more, you can visit the Tulsa Audubon Society’s website.
