Each year they stream by the islands going South. I took this outside the shop just now.
Google said'
Cloudless sulphurs may be found in all habitats when migrating, but breed in disturbed open areas where their caterpillar host plants and nectar plants are found. They have relatively long tongues and can reach the nectar of some tubular flowers that some other butterflies cannot. Red flowers are preferred. common name: cloudless sulphur
scientific name: Phoebis sennae (Linnaeus) (Insecta: Lepidoptera: Pieridae: Coliadinae)