A migrant species from southern Europe and North Africa which sometimes occurs in large numbers in the UK, usually following a long period of warm weather or southerly airflow. It is a scarce species in the Outer Hebrides with 14 records up to 2024. It flies in the sunshine and hovers in front of flowers, sipping the nectar with its long proboscis.

References: 
Leverton, R. & Cubitt, M. (2024). The Larger Moths of Scotland.
Waring, P. & Townsend, M. (2018 third edition). Field Guide to the Moths of Great Britain and Ireland.