This animation shows the lowest temperatures forecast for March 4 to March 8, 2009. Look at the area where the first Ruby-throated hummingbirds were reported. (Scroll down to see the legend.)

• What temperature pattern do you see there?
• How do you think this might affect the hummingbird migration, and why? (Think about their food sources.)

Each colored band shows areas forecast to have the same minimum temperatures on a given day.

Maps: Weather Underground >