An orange-and-black wave is moving south across North America as monarch butterflies embark on one of nature's most remarkable migrations.
As autumn approaches across North America, temperatures fall, daylight fades and milkweed begins to die back. Monarchs born during late summer then begin a journey that can stretch up to 3,000 miles, according to the Xerces Society.
Most monarchs east of the Rocky Mountains fly toward the oyamel fir forests of central Mexico . Many western monarchs migrate toward sheltered groves along the California coast.
Unlike earlier generations, which typically live for only two to six weeks, this migratory "super generation" can survive for up to nine months. The butterflies spend the winter in warmer climates before beginning the return trip north in spring.
When will monarchs pass through?
Monarch butterfly fall migration patterns south, according to Xerces Society maps. Image courtesy AccuWeather
The migration begins during August in southern Canada and the northern United States before gradually shifting south through September and October.
Monarch Watch estimates peak abundance around the Great Lakes and portions of the central United States from ear...