Painted Lady butterflies are still with us as we begin the third week of September. Last week I found a flock of about 150 that were working a flower bed near our home. The count was down to about two dozen on Wednesday.
These aren't birds, but migrants of a different kind, hard to miss right how when we are wandering around with binoculars in our hands. They add pleasure for me on backyard visits or longer trips.
Soon, Painted Lady butterflies will begin a migration equaling or exceeding that of the better-known Monarch butterfly. During fall migration — now — clouds of thousands of Painted Ladies can be seen — if one is lucky.
Monarchs receive and deserve attention because they are imperiled, numbers falling as land uses change on their migration course (Mexico to northern to Canada) Encroachment on the mountainous areas in Mexico where they spend the winter is another factor.
Much of what follows comes from a 2012 article in The Telegraph, a London newspaper. The Painted Lady is found there, too. It can be seen on all continents at some time of the year except South America and Antarctica.
This butterfly is a common migrant, moving south in fall, north in spring. Like Monarchs, the Painted Lady accomplishes this with multiple generations linking themselves on one long trip. Over one year up to six successive generations of Painted Ladies may migrate across Mexico and the U.S.
Questions about the butterfly’s migration were answered in a study in England using radar. In 2009, radar detected an estimated 11 million Painted Lady butterflies returned to England that spring, with 26 million moving south in fall.
In Europe, the migration destination is Africa. Most North American Painted Lady butterflies winter in southern Mexico.
Species joining Monarchs and Painted Lady butterflies in fall migration include Cloudless Sulphur, Little Yellow, Gulf Fritillary, American Lady, Red Admiral, Common Buckeye, Long-tailed Skipper, Clouded Skipper, Fiery Skipper, Sachem, and Ocola Skipper.
Butterflies likely to be seen in large numbers in fall migration include Cloudless Sulphurs, Mourning Cloaks, Question Marks, and especially Queens and Monarchs.
The Telegraph reported that marine radar can pick up flying-insect size, direction, and speed. Migrating butterflies can be hard for us to see because many are flying at altitudes up to 3,000 feet, at speeds up to 30 mph. The Painted Lady weighs less than a gram with a brain the size of a pin head. Migrants have no opportunity to learn from older, experienced individuals.
Many butterfly species overwinter as one of the animal’s four life forms — egg, caterpillar, chrysalis or adult. (Below, a Red Admiral)