Journal archives for March 2019

March 12, 2019

Southwestern U.S. Painted Lady Migration - Enormous and Extensive!

The ongoing Painted Lady migration is well underway, after a seeming delay in some areas due to cool weather. Large numbers were passing through Palm Springs, California on and before March 2, 2019, and some of these butterflies were observed flying westward. They also became abundant in the Las Vegas area around March 4, and continue to be present there in large numbers. Most recently, an enormous swarm has been flying northward through the Los Angeles area, both yesterday and today, March 12. Painted Ladies are now widespread throughout southern California, including in Borrego Springs, where an extensive northward migration was underway on March 11. In Yuma, in the southwestern corner of Arizona, Painted Ladies have likewise been flying in huge numbers for the last two to three weeks, mainly in a northwestern direction. The entire outbreak was likely triggered by considerable local rain associated with the current El Niño event, followed by prolific blooms of desert annuals and growth of larval food plants.

Although the butterflies have often been reported as flying generally northward, there seems to be substantial local variation in flight direction in much the same way as occurred during a similar large and well-observed migration from February through April 2005. You can find out more about the 2005 migration from today's news posting on the Red Admiral and Painted Lady Research Site, https://vanessa.ent.iastate.edu .

Posted on March 12, 2019 20:37 by iowabiologist iowabiologist | 0 comments | Leave a comment

March 19, 2019

California Tortoiseshell - Not a Painted Lady!

Painted and West Coast Ladies are not the only butterflies in the western United States to be undergoing an outbreak. California Tortoiseshells have also been present to abundant in some places in northern California and Oregon where Painted Ladies probably have not yet arrived in any large numbers. They look like this: https://bugguide.net/node/view/1447798. While they are interesting butterflies in their own right, and worthy of further study, they are not Painted Ladies, so please be careful not to confuse the two when reporting Painted Lady sightings. Also, according to a March 18 posting on DesertLeps, California Tortoiseshells have also become abundant in the area of southern California around the Santa Rosa and San Jacinto Mountains National Monument, replacing the Painted Ladies, which are surprisingly not that common there now and seem to have mostly departed the area. However, Painted Ladies were still abundant in southern California on March 16 near the Mescal Range in San Bernardino County, CA, about 138 miles (222 km) to the north-northeast; no California Tortoiseshells were observed there.

Posted on March 19, 2019 16:38 by iowabiologist iowabiologist | 1 comment | Leave a comment