The Streak is one of our common moths and it is found everywhere its food plant Broom grows. Broom is a plant of sandy, well-drained, acidic soils and grows on almost any ridge or slope especially if the soil is disturbed and free from other competitive plants. Broom plants have a life of only a few years and the populations locally can change quite rapidly as old sites become colonised by trees and new sites are created, often by man. The moth finds the new plants to lay its eggs which overwinter and hatch out in late April. The stick caterpillar is bright green, to match the Broom shoots, with a narrow, whitish line along its side.
The adult moth is unusual for a geometrid moth in having a resting position with its wings held like a tent. This is an excellent aid to camouflage the moth when resting on the older stems of Broom. It wraps its wings round the wood with the ‘streak’ and other markings matching the natural patterns of the bark.
The moth is on the wing from September to the end of November with last week and this being when they are most abundant. There are over 400 records from D&G and it is likely that every patch of Broom will be home to this moth.
