of the extraordinarily large migration observed in Israel at the end of March, estimated at a billion individual butterflies. Painted lady migration patterns are highly erratic and they do not migrate every year. Some evidence suggests that global climatic events, such as el Niño, may affect the migratory behaviour of the painted lady butterflies, causing large-scale migrations. The first noticeable wave of migration in eastern Ukraine was noted in the 20s of April 2019. From May 15, numbers began to grow and it was possible to observe hundreds of this species in the Kharkiv region of Ukraine, including in the city streets of Kharkiv. Based on experimental data, the painted lady's migration pattern in northern Europe apparently does not follow a strict north-west heading. The range of headings suggests that migrating butterflies may adjust their migration patterns in response to local topographical features and weather, such as strong wind patterns. Laboratory-raised autumn-generation painted lady butterflies were able to distinguish a southern orientation for a return migration path. According to the same laboratory-based study, when butterflies were isolated from the sun, they were unable to orient themselves in a specific direction, opposed to those that did have access to the sun. This suggests that V. cardui requires a direct view of the sky, implying the use of a solar compass to orient its migratory direction and maintain a straight flight path. Mating behaviour in relation to migration V. cardui displays a unique system of continuous mating, throughout all seasons, including the winter. This may be attributed to its migratory patterns, thus significantly affecting its mating behaviour. During European migrations, the butterflies immediately begin to mate and lay eggs upon arrival in the Mediterranean in the spring, starting in late May. In the United States, painted lady butterflies migrating towards the north experience poor mating conditions, and many butterflies have limited breeding capabilities. The "local adult generation" develops during this time, roughly from the middle of May through early June in conjunction with the butterfly progression throughout their flight. During its migratory process, these painted lady butterflies start breeding, and reproduce entirely throughout their migration. Scientists have not been able to find evidence of their overwintering; this may be because they migrate to warmer locations to survive and reproduce. Female painted lady butterflies may suspend their flight temporarily when they are "ready to oviposit"; this allows them the opportunity to continually reproduce