This webpage contains information about the Small Blue and Sussex Butterfly Conservation’s South Downs Small Blue Survey. Later in the year when Small Blues are on the wing you will be able to add your Small Blue sightings to this page to help us build up a better understanding of the current status and distribution of the Small Blue in Sussex.
In the meantime please read the articles to find out more about the Small Blue, how to identify it and where to look for it.
Special Small Blue events will be held in the Summer and will be advertised later in the year.
To find out more about The South Downs Small Blue Survey please email Michael Blencowe: sussexgrayling@aol.com.
In 2009 the Sussex Branch of Butterfly Conservation (BC) will launch a project to survey and protect the Small Blue Cupido minimus in Sussex.
With support from The South Downs Joint Committee (SDJC) and the Sussex Biodiversity Record Centre (SxBRC) volunteers will survey the county to establish the current status of the butterfly and its habitat in Sussex, promote its conservation needs and offer practical management advice to landowners to help secure its future in the county.
The Small Blue is the smallest British butterfly and requires chalk grassland in the early stages of succession.
The caterpillar almost exclusively eats Kidney Vetch, so the future of every Small Blue colony is dependent upon the annual availability of this plant.
Kidney Vetch is a poor competitor - it thrives well on bare ground but is soon lost in the course of succession, meaning that the dependent Small Blue colonies are vulnerable to extinction.
Habitat management to create the correct conditions for the Small Blue is relatively easy. Simple ground disturbance will create the bare chalk that Kidney Vetch needs to flourish. However grazing, especially by sheep, can be destructive.
There are many opportunities to create connections (habitat 'corridors') between current Small Blue colonies, to help ensure their long-term survival.
The objectives of this project are to:
Encourage people to look for and record Small Blue colonies and send their results to Butterfly Conservation / SxBRC.
Compile an accurate database of the status and distribution of the Small Blue in Sussex.
Raise awareness amongst landowners and site managers of the status and habitat requirements of this species.
Halt the decline of the Small Blue in Sussex by ensuring that sites with surviving populations are managed with the long-term maintenance of the species as a key objective.
Encourage management close to remaining populations that will provide suitable habitat for the Small Blue and enable it to occupy larger areas.
The Small Blue is Britain’s smallest resident butterfly - but because of its size, its dull-blue, almost black colouration and the fact that most colonies are small and confined to sheltered pockets of grassland, it is often overlooked.
In Sussex the butterfly is on the wing from mid-May until late June and emerges in a partial second brood from July through to August, and extremely rarely, and by no means annually, as a tiny third brood in mid September. These general flight times may be earlier or later depending on seasonal weather conditions.
Males set up territories in sheltered positions, perching on tall grass or scrub and will fly out to intercept females. Once mated, the females disperse to lay eggs, but both sexes may be found from late afternoon onwards in communal roosts, facing head down in long grass.
The first brood females lay their eggs singly, tucked into the flower-heads of prominent Kidney Vetch plants in late May and June. The caterpillars, which hatch between 3 and 18 days after laying, can turn cannibalistic if they encounter another caterpillar on their flower-head. The caterpillars burrow into the flowers and feed on developing seeds, but in later instars lose their cannibalistic tendency as they move to the outside of the developing seed heads where they are generally attended by ants, particularly the Black Garden or Field Ant (Lasius niger).
When fully grown (about July) they descend to the ground, where a proportion of the caterpillars will spend the winter amongst vegetation or in soil crevices. They will pupate here in late April and May of the following year, although those that will form the second generation will pupate immediately and hatch as adults about 2 or 3 weeks later.
Males perch in groups on shrubs or tall grasses in sheltered spots, flying out to intercept females. When mated, females spend much time amongst flowers of Kidney Vetch, laying eggs. They will often mate more than once. Both sexes roost in long grass, scrub bushes and taller herbs, which are also used for shelter in bad weather.
Small Blues typically form extremely small, discrete colonies (<30 individuals at peak in most years). These populations fluctuate greatly from year to year, in relation to flowering cycles of the Kidney Vetch.
The Small Blue occurs very locally throughout Britain and Ireland, typically in small populations. The main centres of distribution are the chalk and limestone grasslands of southern England.
The national range of the Small Blue declined by over 50% during the twentieth century and it has become extinct through most of the northern half of England. In many regions it is now reduced to a few small colonies that are vulnerable to extinction. There has also been a considerable decline within its main strongholds of southern England and it has disappeared from numerous sites.
In Sussex the Small Blue is almost completely confined to the South Downs where its larval food plant Kidney Vetch grows. It is less common at the western end of the Downs, where Kidney Vetch is not as abundant as it is in areas east of the River Adur.
On the North Downs in neighbouring Surrey it is reduced to about 15 colonies, most of them extremely small (<10 adults recorded at peak).
The Small Blue relies on chalk grassland habitats that are sheltered and provide a warm micro-climate for the adults.
Its most important habitat requirement is the presence of the caterpillar’s food plant Kidney Vetch and therefore the butterfly is found where this plant flourishes - on sparsely swarded, species-rich grassland or unstable areas subject to soil erosion.
In Sussex it occurs on the chalk grasslands of the South Downs where it can also be found in man-made habitats such as quarries, road embankments, and along tracks and paths.
Small Blue: Habitat
The Small Blue relies on chalk grassland habitats that are sheltered and provide a warm micro-climate for the adults.
Its most important habitat requirement is the presence of the caterpillar’s food plant Kidney Vetch and therefore the butterfly is found where this plant flourishes - on sparsely swarded, species-rich grassland or unstable areas subject to soil erosion.
In Sussex it occurs on the chalk grasslands of the South Downs where it can also be found in man-made habitats such as quarries, road embankments, and along tracks and paths.
The Small Blue caterpillars feed almost exclusively on Kidney Vetch (extremely rarely on Yellow Melilot Melilotus officinalis), so the success of the colony depends on the continued availability of this plant every year.
Kidney Vetch is a poor competitor - it thrives well on bare ground but is soon lost in the course of succession. For this reason patches of bare chalk soil must be available if it is to continue to establish seedlings regularly.
Kidney Vetch is also the main nectar source, although other yellow legumes such as Bird’s-foot Trefoil and Horseshoe Vetch are occasionally used.
The Small Butterfly is Britain’s smallest butterfly - on your first encounter you will be surprised at how small it is!
Wingspan: 18-27mm (compare this to Common Blue 29-36mm) There is variation in size in both sexes - but neither of them are consistently the larger.
Upperside: Another surprise is that the Small Blue isn’t particularly blue. The upperside of the wings can be described as plain brown or smoky black although a light dusting of silvery scales near the base of the wing give a slightly blue appearance. The plain unmarked upperside distinguishes it from other species.
Underside: The Small Blue’s underside is unmistakable; silvery grey and lightly spotted and unlike other blue species which contain orange markings.
Below are our records for the Small Blue in Sussex 2000-7. As you can see the butterfly is found at a number of chalk grassland sites - some of them are in remote Downland valleys others are on road cuttings and Golf Courses. They stretch along the length of the Downs from Eastbourne to Graffham.
However as the Kidney Vetch at these sites disappears through natural vegetation succession so will the Small Blue. We’d like to find out if the butterfly can still be found at these sites. Is there a Small Blue site near you?
Please Note: Many of these sites are on private land (farmland, golf courses) - please ensure you have permission to enter these sites. If you would like to survey on private land please contact us and we will arrange permission.
Also: The Small Blue has colonies in some very dangerous places! Quarries, road cuttings and steep, unstable Downland are all favourites. Please do not risk your neck surveying for Small Blues - we can afford to lose butterfly distribution information but good recorders are hard to come by! Please take care when you are out surveying.
1. Anchor Bottom (site also known Beeding Bostal) TQ205095
2004
2005
2006
2007
2. Beddingham Quarry TQ4306
2002
3. Beeding Cement Works TQ198085
2004
4. Beeding Hill (site also known as Golding Barn) TQ212102
2001
2002
2004
2005
2006
2007
5. Benfield Valley Nr Hove TQ2609
2002
2003
6. Bevendean TQ338067
2000
2001
2002
2003
2004
2005
2006
2007
7. Bible Bottom TQ431100
2005
8. Birling Gap TQ546964
2005
9. Black Cap TQ377126
2005
2006
2007
10. Bo Peep Bostal TQ498050
2000
2007
11. Broadgreen Bottom Nr Peacehaven TQ4203
2002
12. Brownings Farm TQ527202
2007
13. Castle Hill National Nature Reserve TQ371068
2000
2001
2002
2003
2004
2005
2006
2007
14. Cissbury Ring TQ143079
2000
2001
2003
2005
2006
2007
15. Cocking Quarry SU881169
2003
2004
2005
2006
16. Cow Wish Bottom Nr Tarring Neville TQ449038
2002
2003
17. Cradle Hill TQ503013
2001
2004
2006
18. Crowlink TV542978
2004
19. Deep Dean TQ5402
2004
2005
2006
20. Denton TQ4602
2002
2006
21. Durham Farm (Site also known as Tarring Neville) TQ433040
2002
2005
2006
2007
22. Eastbourne TV615995
2005
23. Ewedean TQ532032
2005
24. Farm Hill SU963146
2002
25. Friston Forest TV544991
2005
2006
2007
26. Frog Firle TQ5000 & TQ51,2008
2002
2003
2007
27. Frog Firle Farm TQ507014
2002
2003
2004
2005
2006
2007
28. Fulking Hill TQ2511
2001
29. Gardener’s Hill (Site also known as South Heighton) TQ462030
2002
2006
30. Graffham Down SU917162 & SU920162
2000
2002
2003
2006
31. Hangleton Slip Road TQ264075
2007
32. Heighton Hill TQ4703
2002
33. Heyshott Escarpment SU898168
2006
34. Hollingbury Camp Brighton TQ3208
2003
35. Horseshoe Plantation TV562958
2006
36. Itford Hill / Farm TQ4304
2002
2006
37. Kingston TQ3708 & TQ392087
2004
38. Kingston Hill TQ387078
2006
39. Keymer Turn TQ3113 (Site also known as Underhill Lane)
2004
2006
40. Lancing Clump TQ182063
2003
2005
2006
41. Levin Down SU884133 & SU882013
2001
42. Malling Down TQ428107
2001
2004
2007
43. Medley Bottom Nr. Amberley TQ047123
2000
44. Mile Oak Banks TQ248080
45. Moon Copse Nr Duncton SU964155
2000
2005
46. Mount Caburn TQ445091
2007
47. Newhaven TQ4400
2001
2002
2003
2004
2005
2006
2007
48. Oxteddle Bottom (Site also known as Southerham) TQ436099
2003
2004
49. Rodmell TQ396066
2003
50. Round Hill Banks TQ270078
2007
51. Saltdean TQ390030
2005
2006
52. Seaford Cutting TQ473000
2006
53. Seaford Head TQ493980 & TQ494978
2006
2007
54. Sheepcote Valley Nr Brighton TQ343043
2004
55. Shooters Bottom TV5795
2006
56. Slonk Hill Cutting TQ225065
2007
57. South Heighton Farm TQ451030 & TQ445035
2006
2007
58. Springhead TQ069126 & TQ071124
2000
2001
2002
2003
2004
2005
2006
2007
59. Steep Down Nr Sompting TQ169079
2001
60. Steyning TQ176113
2005
61. Telscombe TQ3903
2003
62. The Trundle – Goodwood Country Park SU878112
2007
63. Upper Beeding Church TQ193113
2003
64. Windover Hill (Site also known as Wilmington) TQ537037
