What makes your county's wildlife special? I sorted 60.9 million openly licensed wildlife records into the 118 vice counties of Britain and Northern Ireland and asked, for each one, which species turn up far more often there than anywhere else.
Every county has a creature that seems to belong to it. Pembrokeshire has its shearwaters, Norfolk its swallowtails, the Scottish islands their corncrakes. Naturalists have long divided Britain into "vice counties", fixed recording areas drawn up in the nineteenth century so that records from different decades can be compared, and the National Biodiversity Network's Atlas now holds hundreds of millions of sightings tagged with them. I used only the records that are openly licensed, and only those since 2000, and asked a simple question of each county: which species make up a much bigger share of its records than they do of the records for Britain and Northern Ireland as a whole?
That share is a location quotient. A bird with a quotient of 10 in a county makes up ten times as large a slice of that county's bird records as it does of all bird records. Comparing shares rather than raw counts matters, because some counties are recorded far more heavily than others: Middlesex has 889 records per square kilometre, Tyrone 35. The map shows each county's strongest signature species. Choose a group, tap a county, or search for any of 2,740 species to see where it is over-represented.
Across all animals, a bird is the signature of 45 counties, a mammal of 33, a butterfly of 26, a dragonfly or damselfly of 8 and an amphibian or reptile of 6. The strongest signals come from species that are common where they occur and almost absent elsewhere: mountain and island specialists, seabird colonies, and a few animals that people introduced to one corner of the country.
The Scotch argus, a dark brown butterfly of damp Highland grassland, is the animal signature of 6 Scottish counties, more than any other species. The hooded crow, which replaces the carrion crow in Ireland and the north west of Scotland, is the signature bird of 6 of the 6 Northern Irish vice counties. Some signatures are introduced: Chinese water deer in the fens, wild boar in the Forest of Dean (West Gloucestershire, 56×), wall lizards on the Isle of Wight, and stoats on Orkney (131×), where they were first reported in about 2010 and now threaten ground-nesting birds.
The Mountain Ringlet makes up 906 times as large a share of butterfly records in Mid Perthshire as it does across the UK. It is the most concentrated signature on the map.
A second question is how different a county's whole list is from the national list. For each group I measured how much of a county's records would have to be moved between species to match the national mix (the "total variation distance", from 0 for identical to 1 for no overlap), then subtracted the distance a random sample of the same size would show by chance, so that thinly recorded counties do not look distinctive just because they are small. Averaged over the five animal groups, Shetland, Orkney and Outer Hebrides are the most distinctive; Derbyshire and South-west Yorkshire are the most typical. On average Scotland's counties score 0.44, Northern Ireland's 0.36, Wales's 0.28 and England's 0.23.
The same records show species arriving. The harlequin ladybird, a non-native beetle first found in Britain in 2004, had records in 72 vice counties in 2000 to 2009 and 91 since 2020. The tree bumblebee, which colonised naturally from the continent, went from 9 to 109. The little egret, a rarity before the 1990s, was recorded at least twice in just 1 vice county in 1970 to 1989 and in 104 since 2020. The ring-necked parakeet, long a London speciality, has records in 56 counties since 2020, against 15 in 2000 to 2009. Recording itself has grown, so these counts show where a species has been seen at least twice in a period, not exact ranges; switch the map to Newcomers to see the order in which counties joined.
111 species in the seven groups have at least 5 records since 2000, all from one vice county. Most are plants (57) and moths (45), many of them garden escapes or recent arrivals; West Cornwall and Berkshire have the most (14 each). The animals among them are a strange crowd: lone vagrants that stayed for weeks, escaped exotic birds, and one famous bat.
Records are not wildlife. They are wildlife multiplied by people looking, and the people are not spread evenly. The median county has 204 open records per square kilometre since 2000; the busiest, Middlesex, has 889. Location quotients compare each county with itself, which removes the overall level of effort, but they cannot remove effort that falls unevenly on particular species, such as a big local survey of one animal.
Records. I queried the NBN Atlas occurrence web service on 29 October 2026 for records that are identified to species, marked as present, dated 2000 or later and published under an open licence: CC0, CC BY or the Open Government Licence. That gives 65,088,580 records (33,444,849 CC BY, 29,897,336 OGL, 1,746,395 CC0), of which 60,917,118 fall in a vice county. Records under CC BY NC, which include large national schemes, are left out, so some groups (moths especially) are thin, and some counties' totals rest on a few big datasets; the county panel lists the largest. I only downloaded counts by county and species, never individual records, and NBN Atlas already blurs the locations of sensitive species.
Counties. The units are the Watsonian vice counties of Great Britain (1 to 112, including the Isle of Man) and the six Irish vice counties in Northern Ireland (H33, H36 to H40), as assigned by the Atlas. They are stable recording areas, close to the historic counties, not today's local authorities.
Groups. Birds, mammals, amphibians and reptiles, dragonflies and damselflies, and flowering plants follow the Atlas's species groups; butterflies are the six butterfly families within Lepidoptera and moths are the rest. Domestic animals were dropped.
Location quotients. For species s in group g and county c, LQ = (records of s in c ÷ records of g in c) ÷ (records of s everywhere ÷ records of g everywhere). To avoid tiny-sample artefacts I only rank species with at least 20 records in the county and 200 in all, only show a group for a county with at least 1,000 records of it (150 for the three small groups), and rank by a cautious version of the quotient that uses the lower end of a 90% Poisson interval for the county count. The page shows the plain quotient.
Limits. A record is a sighting someone chose to submit, so quotients mix where a species lives with where people look for it, and with who shares their data openly. Escaped and vagrant birds can rank highly where a single bird drew many visitors. Seas around a county are partly included, so whales, dolphins and seals appear as coastal signatures. Plant records from the BSBI atlas are counts of grid squares rather than individual sightings. Treat each signature as "recorded unusually often here", not as a census.