Wider Countryside Butterfly Survey

Strong emphasis has been placed on making sure that the WCBS is both scientifically sound (by sampling of the countryside through random sampling) and efficient (a scheme with fewer visits to account for the fact that butterfly species are now uncommon across much of the general countryside).

Through consulting widely in 2005/6 and successful pilot years in 2007/8, the method we have come up with is based on the BTO’s Breeding Bird Survey (the ‘BBS’), counting along two parallel 1-km long transects subdivided into 10 sections, located within randomly selected 1-km squares.  The differences being that butterflies are counted in a more restricted area than for birds and at different times of the day. Only 2-4 visits are required compared to 26 on transects.

Good coverage was achieved across Great Britain with 310 squares surveyed. In total 181 BBS squares were surveyed by 165 recorders, nearly double the prediction, and only 33 squares received just one visit.  99 squares were surveyed by 86 recorders in the four selected Butterfly Conservation Branches (Highland, Norfolk, South Wales, Somerset and Bristol) with a further 30 completed by staff (total= 129). 50 squares were visited during May-June to pick up early flying species. The majority of squares were in England (258) followed by Wales (31), Scotland (20) and one square in Northern Ireland.

In spite of the poor weather 42 butterfly species were seen across the UK, including nearly all of the target wider countryside species (excluding the White-letter Hairstreak), plus a good range of migrants and rarer species such as the Large Heath and White Admiral. On average nearly 100 butterflies and ten species were seen per square based on two summer visits, showing that taking part in this survey in the future should produce a good diversity of butterflies for recorders. There were, however, 15 squares where the recorder saw no butterflies on single visits, although at the other extreme one recorder in Kent counted a staggering 672 butterflies on one visit.  The most species rich squares were in Norfolk and Somerset both with 15 species recorded on single visits. Of particular interest were the high occupancy rates (percentage squares occupied)  of the Small Heath (20%) and the Wall Brown (5%) which are UK Biodiversity Action Plan priority species in decline. It wasn’t just butterflies that caught recorder’s eyes - dragonflies were recorded on more than 50% of squares and day-flying moths were recorded on a quarter of squares.

Wider countryside field testing was repeated in 2008 to further refine field methods and to compare abundance and occupancy (number of squares occupied) in common species between 2007 and 2008 a) within wider countryside squares and b) in comparison to transects.

All recorders that took part in 2007 were invited to take part again in 2008. 192 squares were surveyed in 2008- 62% of last year's total (310). The 38% decrease in uptake was mainly due to very unsettled weather in 2008 and uncertainties over the roll out.

On average 11 species and 104 individuals were seen per square based on 2 summer visits, which is the same as 2007 (10 species and 95 individuals). In total 40 species were recorded in 2008 with 5 species lost compared to 2007 and 3 species gained, all of which are habitat specialists recorded in low numbers. Two key target species of the WCBS are the Small Copper and the Small Heath, both of which increased in abundance and in the number of squares occupied in 2008. The decline in the Small Tortoiseshell was detected using the new method, with 17% fewer squares occupied in 2008. Overall the occupancy figures were relatively stable which is to be expected over a short time scale and provides evidence that the method is robust.

Following four years of pilot studies, the WCBS was formally launched in 2009. The WCBS is the first UK-wide survey of butterfly abundance based on random sampling. In spite of limited resources for promotion, there was a fantastic response by volunteer recorders. In total 1642 visits were made to 763 1-km squares (see map) by 611 recorders, who collectively walked 3300 km of survey line, counting 119,000 butterflies of 47 species.

The full feedback newsletter can be downloaded here.

The most widely recorded species over the core July and August period was the Large White, occurring in nearly 90% of squares, whilst the most abundant species was the Meadow Brown with approximately 15,000 individuals counted. Two Browns (Meadow Brown, Gatekeeper) and three Whites (Large White, Small White, Green-veined White) accounted for two thirds of all butterflies counted.

On average, recorders saw 11 species and 160 butterflies per square (based on two visits). This represents a marked increase in numbers from the pilot study years, when around 100 butterflies were seen in the same period. This increase could be due to a good year for migrant species such as the Painted Lady which was present in 83% of squares and ranked 4th in total abundance compared to 2008 when it ranked 26th and also Large White which jumped three places to 1st position in 2009. Encouragingly the Small Copper, a species of intermediate range and abundance, was seen in over a quarter of squares and moved five places up the table to become the 14th most commonly seen species.

Looking back to 2008, butterfly numbers are up by nearly a third and 1-2 more species were seen per visit. With three years of data from 2007-2009 we will be able to look at changes in butterfly abundance in the wider countryside and the possible reasons for change.

The Insect Flower Search Pilot study was very successful with around a third of recorders taking part. The Common Carder Bumblebee was the most widespread species and the Marmalade Hoverfly was the most abundant. The pilot study will not be continuing in 2010 but it shows that recorders are keen to look for other insects in the countryside.

The Wider Countryside Butterfly Survey (WCBS) is the main scheme for monitoring population changes of the UK's common and widespread butterflies. The survey is a partnership project run jointly by Butterfly Conservation, the British Trust for Ornithology (BTO) and the Centre for Ecology and Hydrology (CEH). We now have five years of data (including the pilot years of 2007 and 2008) from the Wider Countryside Butterfly Survey (WCBS). In 2011, 723 squares were surveyed by 523 recorders who counted in excess of 67,000 butterflies of 45 species. This is a fantastic recording effort and we wish to thank everyone who took part.

The newsletter of the 2011 results can be downloaded here.

On average recorders saw 47 butterflies of seven species per survey made over July and August compared to 60 butterflies of 7 species per survey in 2010. These data support anecdotal observations that 2011 was a relatively poor year for common and widespread butterflies. Almost two-thirds of the butterflies seen comprised of Meadow Brown, Small White, Green-veined White, Large White and Gatekeeper. The most widespread (and abundant) species was the Meadow Brown occurring in over 80% of squares.

Due to a grant from Scottish Natural Heritage coverage was boosted in Scotland, giving more representative coverage for a number of northerly distributed species including Scotch Argus. The Essex Skipper had a good year as did the Red Admiral. However, it wasn't all good news; both the Small Tortoiseshell and Common Blue had poor years.

Participants once again recorded day-flying moths in 146 squares, Silver-Y was the most widespread species and Six-spot Burnet was the most abundant. Dragonflies and damselflies were recorded in 222 squares Common Darter was the most widespread and abundant species for the third year running.

The Wider Countryside Butterfly Survey (WCBS) is the main scheme for monitoring population changes of the UK's common and widespread butterflies. The survey is a partnership project run jointly by Butterfly Conservation, the British Trust for Ornithology (BTO) and the Centre for Ecology and Hydrology (CEH). We now have six years of data (including the pilot years of 2007 and 2008) from the Wider Countryside Butterfly Survey (WCBS). In 2012, 771 squares were surveyed by 648 recorders who counted in excess of 64,000 butterflies of 46 species. This is a fantastic recording effort and we wish to thank everyone who took part.

The newsletter of the 2012 results can be downloaded here.

It was a good year for some of the grass-feeding Satyrid (Brown) species. For the fourth consecutive year Meadow Brown was the most abundant butterfly with 18,629 individuals counted. It was also the most wide spread species occurring in almost 90% of squares. Meadow Brown, Gatekeeper, Small White, Ringlet and Green-veined white accounted for over two-thirds of butterflies observed.

For the majority of species it was a poor year – the worst in a four year series. There has been a year-on-year decline in mean butterfly abundance in each year of the WCBS. On average, recorders saw 44 butterflies of four species per survey made over July and August compared to 80 butterflies of 8 species per survey in 2009.

Participants once again recorded day-flying moths in 222 squares, Silver-Y was the most widespread and abundant species. Dragonflies and damselflies were recorded in 259 squares; Common Blue Damselfly was the most abundant species and Common Hawker the most widespread species.

To take part in the WCBS please contact the WCBS co-ordinator:

Dr Zoë Randle

Butterfly Conservation
Manor Yard
East Lulworth
Wareham
Dorset
BH20 5QP

Tel: 01929 406006
Email: survey@butterfly-conservation.org

To take part on an existing BTO BBS square please contact the BBS National Organiser:

Kate Risely

BTO
The Nunnery
Thetford
Norfolk
IP24 2PU

Tel: 01842 750050
Email: bbs@bto.org

The online data entry system is available to use. Please enter your data by the end of September.
Enter your data online

1. WCBS Guidance for surveys on butterfly only squares (i.e. not BTO BBS squares)
2. WCBS Guidance for BTO BBS recorders
3. WCBS recording form (for all recorders)
4. Landowner letter
5. Health and safety note