Garden Butterfly Boom

Posted 26 Nov 2012

After a run of dismal summers, not to mention a late start to spring this year, our butterflies were sorely in need of a spell of dry, warm weather. Thankfully this summer delivered and results from the British Trust for Ornithology’s (BTO) Garden BirdWatch weekly survey, show that many species recovered spectacularly.

The late spring delayed the emergence of many garden butterflies, producing sharp peaks in activity rather later into the year than is usual. Many species were present in numbers well below what would more normally be seen in the Garden BirdWatch figures for early summer and BTO researchers were initially uncertain as to whether this would be another bad year for butterflies.

However, the summer soon turned into a glorious one and many butterfly species responded with sudden and dramatic increases in numbers. There were barely any Meadow Brown butterflies seen in Garden BirdWatch gardens at the end of June – the start of their usual flight period – but by mid-August they were reported in almost 25% of gardens. This is up 56% from last year, which is excellent news as the species has been declining nationally. Small Tortoiseshells had a less dramatic increase but were still seen in 46% more gardens this summer than in 2012. 

The most impressive story of the year, however, belongs to the Peacock. This species overwinters as an adult, and was slow to emerge this year, with activity initially peaking about three weeks later than normal. However, once the weather improved and the first brood of the summer started to emerge, it did much better than in recent years. At the end of July, only 3% of Garden BirdWatch gardens had reported Peacocks but by the end of August, there were reports from 47% of gardens, which was 68% up on what was recorded in 2012. 

To find out more about the BTO Garden BirdWatch, ask for a free information pack which includes a copy of their quarterly magazine. Email [email protected], telephone 01842 750050, or write to GBW, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU.

by Simon Byland