Vanessa cardui migrations take place at high altitude, which explains why these migrations are seldom witnessed. "V. cardui" is known for its distinct migratory behavior. In California, they are usually seen flying from north to northwest. These migrations appear to be partially initiated by heavy winter rains in the desert where rainfall controls the growth of larval food plants. 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 behavior of the painted lady butterflies, causing large-scale migrations. Based on experimental data, the
Black and white some of the early home computers; this was to accommodate black-and-white TV sets, which would display a color signal poorly. (Typically a different shading scheme would be used for the display in the black-and-white mode.) In computing terminology, "black-and-white" is sometimes used to refer to a binary image consisting solely of pure black pixels and pure white pixels; what would normally be called a black-and-white image, that is, an image containing shades of gray, is referred to in this context as grayscale. Black and white Black-and-white (B/W or B&W) images combine black and white in a continuous spectrum, producing a