It is always exciting when the first spring butterflies are sighted. On a mild and sunny morning in mid-March I saw three Brimstone butterflies, two males and one female, flying around the Home Wood area of the Gardens. The male Brimstone (left) is a lovely bright yellow, the female (below) is a pale greenish white. They have a very characteristic shape, resembling a leaf when roosting with closed wings.
Brimstone butterflies are one of the species that hibernate over winter. They seek a sheltered woodland spot amongst holly or ivy and re-emerge on the first warm days of spring with a peak flight period of April and May. They lay their eggs on Alder Buckthorn . These then mature into adult butterflies which emerge in August, providing another peak. In autumn the butterflies can be seen feeding on nectar as they build up their fat reserves in preparation for hibernation.