We are working on bringing you the full 2020 Butterfly Report, which has sent us trawling through our database of butterfly records. The number of butterflies counted from the mid 1990s to May 2021 is 5,608,000, which is actually an under-estimate, as some of our records are received in bands, to allow estimation of numbers. For example, Band B, is 2-9 butterflies, band E is more than 100. To calculate the total, we have taken the lowest figure for each band, so the real total is undoubtedly higher.
The number of records is 1,271,392. A record is the sighting of one or more of a species of butterfly in a place on a particular date. So you might report three Peacock, two Small Tortoiseshell and one Painted Lady seen on your buddleia today: that would be three records, one record for each species.
Of this 1.2 million records, 700 were eggs, caterpillars or chrysalises, which might suggest these other life stages are being under-reported, so please note this, and if you spot an Orange Tip egg on some garlic mustard, let us know via our recording form.
A number of factors are leading to a considerable increase in the amount of data being received. One of these is the creation of this website with its easy recording form. In 2014, the first year of the recording form,this website had sightings of 37,717 butterflies sent in; the figure for 2020 was 91,098.
There is also a big input from the Big Butterfly Count, run nationally in the summer; this started in 2010 and in 2020 added a further 27,200 sightings to our total. There is also a slowly increasing input from online wildlife recording sites such as iRecord and LivingRecord.
This data combines to tell us, both locally and nationally, how each species of butterfly is doing, and if a species is in trouble, try to help them. Dorset’s closest-to-extinction species is the Small Pearl-bordered Fritillary, and we are pleased to say that the one remaining colony is on land owned by the National Trust, who are making great efforts to save it.