Macroglossum stellatarum feeds by hovering in front of a flower and extending a proboscis roughly 25 to 28 millimetres long. Its wings beat at a rate high enough to produce a clear hum, and it moves between flowers in short darting hops. To a casual observer in a European garden the impression of a very small bird is strong, and wildlife recorders receive reports of hummingbirds every summer.
Hummingbirds are restricted to the Americas and have no wild European populations. The similarity is convergent evolution: hovering to feed from flowers imposes similar demands on body proportion, wing motion and control, and both lineages arrived at comparable solutions. The moth achieves stable hovering partly through fast visual feedback, tracking the flower and compensating for its movement in wind.
Unlike most hawkmoths this species flies by day and in bright sun. It migrates north across Europe in spring and summer, reaching Britain and Scandinavia, and has been shown to overwinter as an adult in parts of southern Europe. How far north it can now survive winter is changing and is not settled.