Rare immigrant from southern Europe, appearing in southern England irregularly in the 20th Century. In the past two decades occurrences have been almost annual and signs that it may be on the verge of local colonisation. In our area, there have been six recorded on the Isle of Wight since 2009. Surprisingly, Hampshire had to wait until 2022 for the first mainland record, and in line with national trends it appears to becoming more regular on an annual basis. Wingspan 65-80 mm. The main confusion species are the very much more common
Red Underwing C. nupta, which has the forewing more mottled and fasciae less deeply dentate, hindwing with dark marginal band somewhat narrower and its distal edge more irregular, and
Dark Crimson Underwing C. sponsa, which has the forewing darker with reniform stigma large and pale (MBGBI Vol 10). Larva feeds on Grey Willow, Crack Willow, Black Poplar and White Poplar.