Select58.013Brimstone
Select61.015Brown Argus
Select61.003Brown Hairstreak
Select59.028Camberwell Beauty
Select58.010Clouded Yellow
Select59.031Comma
Select61.018Common Blue
Select59.019Dark Green Fritillary
Select57.001Dingy Skipper
Select60.001Duke of Burgundy
Select57.005Essex Skipper
Select59.011Gatekeeper
Select59.013Grayling
Select61.005Green Hairstreak
Select58.008Green-veined White
Select57.002Grizzled Skipper
Select59.020High Brown Fritillary
Select61.012Holly Blue
Select61.013Large Blue
Select59.004Large Heath
Select57.009Large Skipper
Select59.029Large Tortoiseshell
Select58.006Large White
Select61.008Long-tailed Blue
Select59.012Marbled White
Select59.033Marsh Fritillary
Select61.017Mazarine Blue
Select59.010Meadow Brown
Select59.001Monarch
Select58.003Orange-tip
Select59.024Painted Lady
Select58.011Pale Clouded Yellow
Select59.026Peacock
Select59.014Pearl-bordered Fritillary
Select59.022Purple Emperor
Select61.004Purple Hairstreak
Select59.023Red Admiral
Select59.009Ringlet
Select61.014Silver-studded Blue
Select59.017Silver-washed Fritillary
Select61.001Small Copper
Select59.005Small Heath
Select59.015Small Pearl-bordered Fritillary
Select57.006Small Skipper
Select59.027Small Tortoiseshell
Select58.007Small White
Select59.003Speckled Wood
Select59.002Wall Brown
Select61.006White-letter Hairstreak

Start year.   Note that recording prior to ~1995 was too sporadic and inconsistent to be useful here.
 
Stable


Interpretation
These charts need to be interpreted with care. No claim is made that the true abundance trend is indicated. What is plotted (red bars) is the total number of individuals of the selected butterfly species reported from across North Wales for each recording year. This number is influenced by the actual population size but also, crucially, by the number of recorders and the effort put into recording by individual recorders. To a certain extent it is possible to correct for overall recording effort by adjusting for the number of recorders in each year. (Big Butterfly Count records and recorders are excluded as being atypical). However, what can't be done is to adjust for the varying effort made by individual recorders. The green line shows the abundance figures corrected for the number of butterfly recorders in each year with the numbers normalised so that the total count for all years equals the the actual total count. The blue line is a least squares fit to the green line. It should be understood that the plots are generated from scratch when requested and thus reflect the current contents of the database. On a later date, when further records have been added, the plots may appear different.