Skip Navigation LinksHome » Map » Sites List » Porton Down

Porton Down

Here we provide all the information we have for each transect site.

For example, clicking on one of the section titles below will display the site description (shown automatically), as well as a list of the species recorded here, and their yearly counts. However, you can also chose to Show All the sections, or even Hide All, if you so wish.

Map of Porton Down

The map shows you the route that this butterfly transect follows.


County : England(Wiltshire)
Gridref : SU240350
Year established : 1994
Number of sections : 15
Altitude (m) :
Length (m) : 2700
Width (m) : 5
Broad habitat : Dry semi/unimproved (flower rich) chalk/limestone grassland
The following species have been recorded on this site:
SpeciesStatusColonised / ExtinctMean Count 
Essex/Small SkipperDeclining 16.69 more
Small SkipperDeclining 9.70 more
Essex SkipperDeclining 2.11 more
Silver-spotted SkipperStable 65.93 more
Large SkipperStable 5.48 more
Dingy SkipperStable 24.55 more
Grizzled SkipperStable 22.76 more
Clouded YellowStable 0.76 more
BrimstoneIncreasing 27.02 more
Large WhiteStable 20.39 more
Small WhiteStable 16.13 more
Green-veined WhiteIncreasing 2.13 more
Orange-tipStable 0.43 more
Green HairstreakStable 17.18 more
Brown Hairstreak? 1 more
Small CopperStable 36.36 more
Small BlueDeclining 5.48 more
Brown ArgusStable 53.04 more
Common BlueStable 253.83 more
Chalk Hill BlueDeclining 8.84 more
Adonis BlueStable 1.15 more
Holly BlueStable 1.11 more
Duke of BurgundyStable 0.72 more
Purple Emperor? 0.08 more
Red AdmiralStable 2.46 more
Painted LadyStable 2.71 more
Small TortoiseshellStable 4.89 more
PeacockIncreasing 14.76 more
CommaStable 0.69 more
Pearl-bordered Fritillary? 0.22 more
Dark Green FritillaryStable 196.60 more
Silver-washed FritillaryStable 0.39 more
Marsh Fritillary? 0.04 more
Speckled WoodIncreasing 4.20 more
Wall? 0.29 more
Marbled WhiteDeclining 84.11 more
Grayling? 0.22 more
GatekeeperStable 6.66 more
Meadow BrownStable 1727.94 more
Small HeathStable 272.48 more
RingletStable 11.16 more

This table shows the species that have been recorded on this site. Where sufficient data is available, trends in abundance are assessed and colonisation/extinction events are identified. Click on 'more' to see a plot of abundance through time for each species. See green question mark above for more details.


The UKBMS is run by  Butterfly Conservation (BC), the Centre for Ecology and Hydrology (CEH) and the British Trust for Ornithology (BTO), in partnership with the Joint Nature Conservation Committee (JNCC), and supported and steered by Forestry Commission (FC),  Natural England (NE), Natural Resources Wales (NRW), Northern Ireland Environment Agency (NIEA), and Scottish Natural Heritage (SNH). The UKBMS is indebted to all volunteers who contribute data to the scheme.