Normalized Weekly Abundance

The periods of 1990-2002 and 2003-2015 were analysed and displayed separately to allow any shift in flight time over the last 26 years to be discerned. The tick marks on the week number axis are between the two bars for that week's data. (This is how Google Charts does it). The heights of the bars of the two periods have been normalized to show abundance as if the same number of records had been submitted during each period. This allows crude comparison of the species' abundance in both 13-year periods.
 

Dingy Skipper



 

Grizzled Skipper



 

Essex Skipper



 

Small Skipper



 

Large Skipper



 

Orange Tip



 

Large White



 

Small White



 

Green-veined White



 

Clouded Yellow



 

Brimstone



 

Wall Brown



 

Speckled Wood



 

Small Heath



 

Ringlet



 

Meadow Brown



 

Gatekeeper



 

Marbled White



 

Silver-washed Fritillary



 

Dark Green Fritillary



 

White Admiral



 

Purple Emperor



 

Red Admiral



 

Painted Lady



 

Peacock



 

Small Tortoiseshell



 

Comma



 

Duke of Burgundy



 

Small Copper



 

Purple Hairstreak



 

Green Hairstreak



 

White-letter Hairstreak



 

Black Hairstreak



 

Small Blue



 

Holly Blue



 

Brown Argus



 

Common Blue



 

Chalkhill Blue