Holly Blue (Celastrina argiolus)

The Holly Blue is the first of the blue butterflies to emerge in the spring. It usually flies high around trees and bushes, unlike other grassland blues which usually stay near ground level. It is the commonest blue butterfly to be seen in parks and gardens, and is usually found around holly and ivy bushes.

Spring larvae feed on the flower buds, berries, and terminal leaves of holly, and summer larvae feed on ivy. Spring larvae can complete their development entirely on leaves of male holly bushes, although they prefer female bushes. They also eat a wide variety of other wild and garden plants such as bramble, dogwood, spindle, gorse and snowberry.

The Holly Blue's numbers fluctuate from year to year. They can be found in a wide range of habitats, such as hedgerows, edges of fields, woodland rides, churchyards (where holly and ivy are present), and parks and gardens both in urban and suburban areas.