These three whites, which are among the commonest species in Britain, fly together and can be difficult to distinguish in flight, especially the Small and Green-veined. Female Brimstones and female Orange Tips fly at the same time to add to the confusion. Because it is not easy to distinguish the Small and G-V Whites in flight, I tend to apportion total numbers seen pro rata with those positively identified. Thus if I see 12 smallish whites in total on a day, and have positively identified settled specimens of two Small and one G-V White, then I record them as 8 Small and 4 G-V Whites.

The Large and Small Whites are collectively called Cabbage Whites by the gardening public, whose main interest in them is usually the damage their caterpillars do to members of the cabbage family. Most laymen probably inadvertently class the innocent Green-veined White with them as well, although these (in gardening terms) only eat weeds.

The Large White is the least abundant of the three, and perhaps the most easily distinguished with its bigger size, blacker markings and more powerful flight. Migrants from the continent reinforce its numbers every year. It is seen in small numbers in May and June, and in larger numbers from July to September.