Vanessa cardui is the most widespread of all butterfly species. It is commonly called the painted lady, or formerly in North America the cosmopolitan. Description Distribution V. cardui is one of the most widespread of all butterflies, found on every continent except Antarctica and South America. In Australia, V. cardui has a limited range around Bunbury, Fremantle, and Rottnest Island. However, its close relative, the Australian painted lady (V. kershawi, sometimes considered a subspecies) ranges over half the continent. Other closely related species are the American painted lady (V. virginiensis) and the West Coast lady (V. annabella). Migration V. cardui occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn. It migrates from North Africa and the Mediterranean to Britain and Europe in May and June, occasionally reaching Iceland, and from the Red Sea basin, via Israel and Cyprus, to Turkey in March and April. The occasional autumn migration made by V. cardui is likely for the inspection of resource changes; it consists of a round trip from Europe to Africa. For decades, naturalists have debated whether the offspring of these immigrants ever make a southwards return migration. Research suggests that British painted ladies do undertake an autumn migration, making round trip from tropical Africa to the Arctic Circle in a series of steps by up to six successive generations. The Radar Entomology Unit at Rothamsted Research provided evidence that autumn migrations take place at high altitude, which explains why these migrations are seldom witnessed. In recent years, thanks to the activity of The Worldwide Painted Lady Migration citizen science project, led by the Barcelona-based Institute of Evolutionary Biology (Catalan: Institut de Biologia Evolutiva), the huge range of migration has begun to be revealed. For example, some butterflies migrated from Iceland to the Sahara desert, and even further south. V. cardui is known for its distinct migratory behaviour. In California, they are usually seen flying from north to north-west. These migrations appear to be partially initiated by heavy winter rains in the desert where rainfall controls the growth of larval food plants. In March 2019, after heavy rain produced an abundance of vegetation in the deserts, Southern California saw these butterflies migrating by the millions across the state. Similarly, heavier than usual rain during the 2018-2019 winter seems to have been the cause