Green type = apparent long term increase Red type = apparent long term decrease Grey type = no long term change
Butterflies 2019
Transect results
IoA = Index of abundance, figures in brackets are for 2014, 2015, 2016, 2017 & 2018
++ = Overall increase + = increase over last year = = no change - = Decrease from last year -- = Overall decrease
NB. Dates are for the transect week beginning, not the actual date seen, apart from casual records.
Significant increases were noted for Large Skipper, Orange Tip and Gatekeeper, and significant decreases for Brimstone and Green-veined White, while five species also increased and nine decreased, though in the latter case it was partly due to the very large numbers counted previously rather than anything significant. For example the White Admiral decreased despite having its best count on one day since 2014 - after that it seemed to fade from the scene all too quickly - unlike at Somerford Common. Despite all being over by mid-May, the Orange Tip will be the memorable butterfly for me this year. Brown Hairstreak was easily the least obvious of the Hairstreaks despite the huge egg count last winter.
= Small Skipper Two singles on 8/7 and 12/8, IoA 2 (17,11,1,0,2) - virtually non existent here since 2016
(Essex Skipper - none. Only found in 2015 - (0,1,0,0,0) - probably not overlooked either, now that Small Skipper is so scarce.)
++ Large Skipper Seen from 3/6 - 29/7, max 7, 8/7 IoA 20 (7, 12,12,11, 15) - unlike the Small Skipper obviously on the steady increase here.
-- Brimstone From 15/5 - 9/9, max. 10, 29/7 IoA 43 (65,69,100,57,61) - the lowest ever result
- Large White From 22/4 - 26/8, max. 7 IoA 26 (7,29,29,14,97) - return to normal after last year's good result
- Small White From 8/4 - 16/9, max. 5, 2/9 IoA 13 (0,0,25,10,43)
-- Green-veined White From 22/4 - 9/9, max. 11, 22/7 IoA 43 (174,75,58,69,122) - by a long way the poorest year
++ Orange Tip From 15/4 - 13/5, max. 13, 22/4 IoA 42 (19,24,33,39,27) - the only "white" to do well this year, its highest result so far
(Brown Hairstreak None. IoAs including this year are: 0,1,2,0,1,0. Only one adult seen - a female flying in the Ash tree visible from the new picnic table on 13/9, and no other adults have yet been reported from the reserve by anyone else.)
- Purple Hairstreak From 1/7 - 12/8, max. 7, 15/7 IoA 18 (1,7,2,2,6,60) - still more obvious than usual
- White-letter Hairstreak Two singles on 1/7 and 15/7 IoA 2 (0,1,0,0,5) - comment as above - Darcia Gingell saw 4 on 11/7
(Brown Argus None. Only one seen - on transect last year. IoAs: 0,0,0,0,1,0)
- Common Blue Two singles, 12/8 and 19/8 IoA 2 (4,2,0,8,9) - probably breeding in the Newt Pond Area
++ Holly Blue From 22/4 - 19/8, max. 3, 13/5 IoA 9 (2,6,4,6,7) - always few but better than any previous year
- White Admiral From 1/7 - 29/7, max. 11, 1/7 IoA 19 (54,32,15,22,23) - Despite the good start with the first double-figure count in five years, in the end it was a poor year, unlike at Somerford Common
+ Red Admiral From 29/4 - 2/9, max. 3, 2/9 IoA 11 (8,5,8,26,5)
++ Painted Lady Two on 19/8, one on 26/8 IoA 3 (0,0,1,0,0) - only 3 - but the best ever!
(Small Tortoiseshell None on a transect visit (as in 2016) but one seen on the transect route on 14th July by WOS members! IoAs 2,5,0,1,2,0)
+ Peacock From 8/4 - 12/8, max. 19, 29/7 IoA 52 (129,76,28,15,18) - the last two years seem to have reversed the rapid decline of the previous three.
= Comma From 29/4 - 23/9, max 5, 29/7 IoA 26 (27,32,29,40,26) - pretty even results over the years
- Silver-washed Fritillary From 24/6 - 19/8, max. 32, 15/7 IoA 140 (153,126,91,127,142) - another good year. Valesina females were seen on 12th and 14th July.
- Speckled Wood From 22/4 - 23/9, max. 18, 26/8 IoA 195 (159,146,229,242,256) - a slight setback to the rise since 2016.
= Marbled White Three singles on 24/6, 1/7 & 15/7 IoA 3 (0,3,0,3,3) - probably vagrants from the meadows
++ Gatekeeper From 8/7 -19/8, max. 31, 29/7 IoA 77 (41,43,20,32,33) - by a long way the best year here, as elsewhere.
+ Meadow Brown From 10/6 - 19/8, max. 140, 1/7 IoA 481 (342,363,239, 1055, 370) - But for the astonishing year in 2017 this would have been the best so far.
- Ringlet From 24/6 - 12/8, max. 77, 8/7 IoA 188 (86,89,72,253,200) - it looks like the increase from 2017 is here to stay.