Hawk-moths are large, exotic-looking moths which mostly inhabit tropical areas. Of the 17 species of hawk-moth in Britain, only 9 are permanent residents. They are supposedly named after hawks because of their size (the largest has a wingspan of 10cm) and ability to hover. You can recognise the larvae by their characteristic horn at the rear end. They tend to be larger than the average caterpillar, growing up to 10cm in length. Many hawk-moth species found in Britain migrate hundreds of miles from Southern Europe and Northern Africa. They are very strong fliers and can reach speeds of up to 15 miles an hour. Many hawk-moths are named after their main food plant, hence the privet, bedstraw, spurge and convolvulus hawk-moths. They mostly feed on trees and various weeds and are unlikely to be a pest in the garden, although some species will feed on fuschia. To attract hawk-moth adults into your garden, plant honeysuckle, jasmine, petunia or sweet tobacco as a source of nectar.
2003 saw an explosion in the number of Hummingbird hawk-moths (Macroglossum stellatarum) as summer visitors to the UK, prompting a number of sightings of "hummingbirds" by the general public. These large moths (40-50mm wingspan) look just like small hummingbirds as they sip nectar in flight and are unusual in that they fly during the day.
The Death's-head hawk-moth Acherontia atropos is so called because of skull-like markings on the thorax. You have probably seen an artistically enhanced version of it on a poster for the film "The Silence of the Lambs".