Data from the British Trust for Ornithology (BTO) Garden BirdWatch survey, carried out by volunteers across the UK,
show a fourfold increase in the number of gardens recording a Hummingbird Hawkmoth, making 2022 a record year.
These large, colourful insects are often mistaken for hummingbirds because of the way they hover over flowers and use their long tongues to drink the nectar.
You are mostly likely to see a Hummingbird Hawkmoth in the UK during July and August. Last month, 5.2% of Garden BirdWatch gardens recorded a visit from a Hummingbird Hawkmoth, compared to just 1.3% in a typical year, while the proportion rose to 7.5% in southeast England. In Scotland, where the species is much rarer, it was reported from 1.2% of gardens, more than three times the summer average.
Hummingbird Hawkmoths are particularly fond of pink and purple flowers like Buddleia, Red Valerian and Vipers Bugloss. Watching these plants on warm, sunny days is the best way to spot one yourself. Just look out for a chunky moth with orange wing patches and black stripes on its body.
The influx probably has its origins in the current long spell of warm, southerly winds that carry the moths north from their Mediterranean strongholds. There is also a possibility that rising temperatures mean a growing number are able to overwinter in the UK: in suitable conditions, Hummingbird Hawkmoths will spend the colder months tucked away in thick vegetation, a tree hollow or even a garden shed.
While most Hummingbird Hawkmoths recorded in the UK are thought to be visitors from overseas, a number do breed here, laying their bluish-green eggs on plants such as cleavers (sticky-weed) and bedstraws. A single female can produce as many as 200 eggs that grow into stripy green caterpillars up to six centimetres long.
Rob Jaques, BTO Garden BirdWatch Supporter Development Officer, said: ‘The striking appearance and unusual behaviour of the Hummingbird Hawkmoth means the species attracts lots of attention from gardeners and nature lovers alike. Thanks to the citizen scientists who record these and other species in their gardens, BTO Garden BirdWatch is able to track the fortunes of the wildlife on our doorstep and learn how our green spaces can best support biodiversity.’
He continued: ‘As climate change has an ever more obvious impact on the species we see around us, the data our amazing volunteers collect has never been more valuable than it is today.’
BTO Garden BirdWatch is free to join and a brilliant way to make a difference for science and conservation. Find out more at www.bto.org/gbw
