It's time for monarchs to take flight and migrate
Updated 1:22 pm, Saturday, September 8, 2012
Get ready to watch a pageant of monarch butterflies pass through our area.
People in Canada were witnessing monarchs heading south during the third week of August. We have seen a few over Southeast Texas since then, and more will soon follow.
Monarchs breed across much of North America. Autumn's shorter daylight and cooler temperatures signal newly emerged monarchs to stop reproducing and head to their winter home in central Mexico, following one of three migratory pathways. One population migrates from the West through Arizona and New Mexico. Another population heads from central Canada, the Midwest and Great Plains to funnel through central Texas. Eastern monarchs fly along the Appalachian Mountains and Atlantic seaboard to ultimately follow the Texas coast to Mexico.
Research has shown that some monarchs spend the winter along the California coast, and a few others remain along the coasts of Texas, Louisiana and Florida.
Nonetheless, cold fronts sweeping across Canada and the northern states in September will send millions of monarchs sailing south. They will reach Texas by late September and peak in number during October. The largest concentrations of migrating monarchs typically cross the U.S.-Mexico border around Del Rio in the last half of October.
Monarch migration facts
- Millions of monarchs migrate through Texas from September to early November on the way to winter homes in the mountains of central Mexico.
- Peak migration is during October.
- Some go only as far south as the Texas coast.
- Monarchs spend the majority of their lives as larvae and metamorphose into winged creatures for a few weeks except for the longer-lived nonbreeding migratory monarchs.
- Breeding monarchs on northern grounds will produce several generations before the last, nonbreeding generation in late summer begins migrating.
- Nonbreeding monarchs may live long enough to make the long-distance flight to Mexico and begin the return trip in spring.
While returning north, most will lay eggs at various points along the way, die and leave their progeny to complete the trip.
- A few may make it back to breeding grounds in the southern tier of their range.
- Some monarchs reside on the Texas coast all year.
Track monarch migration on the web: www.learner.org/jnorth/monarch
Unfortunately, the nectar-dependent butterflies going through the Midwest and parts of central Texas will arrive after an unprecedented drought, resulting in sparse wildflowers and few natural sources of nectar. However, this year's summer rains in southeast Texas have yielded nectar-rich flowers in most neighborhoods and parks. So monarchs making their way from the East Coast and Mississippi River Valley should have sufficient food to nourish them when they arrive.
By Thanksgiving, most monarchs will have settled into reserves set aside by the Mexican government in the mountainous oyamel fir forests of the state of Michoacán. They'll be in a state of diapause, or nonbreeding, but will return north in the spring to breed a new generation of orange-winged jewels.