Dräktvariation hos skärpiplärka Anthus petrosus littoralis och vattenpiplärka Anthus spinoletta i vinterdräkt

Plumage variation in nine neutral (i. e. not concerning colour hues) characters was studied from October through February in 77 Rock Pipit Anthus petrosus littoralis and 47 Water Pipit Anthus spinoletta in southern Sweden. The Rock Pipit generally showed more variation than the Water Pipit. Several characters were overlapping between the species, while especially streaking on the underparts significantly distinguished between them. The most reliable differences concerned the width and sharpness of the streaks on the lower breast, and on the anterior and, especially, rear flanks, the Water Pipit having considerably thinner and more clearcut streaks than Rock Pipit.