In the spring and summer a good selection of butterflies can be seen around Royston, particularly on Therfield Heath.

 

Royston, and in particular Therfield Heath, supports many types of butterfly which make excellent subjects for observation or photography during the (supposedly!) hot summer months when bird interest is relatively low. Therfield Heath is renowned as being one of the best sites in England for observing the Chalkhill Blue, which is on the wing in July and August. The caterpillars of Chalkhill Blue feed on Horseshoe Vetch, which is common here. Other butterflies of the Heath include Small Copper, Common Blue, Large, Small and Essex Skippers, Brown Argus, Small Heath and Marbled White. I discovered a colony of White Letter Hairstreaks, a butterfly that spends most of its life in the tops of Elm trees, here and am now (2017) aware of several other small colonies of this species in the area surrounding The Heath. Dark Green Fritillaries have established themselves again on The Heath since 2010 and are now not only doing well here but also spreading into other areas nearby. Good numbers of migratory butterflies such as Painted Lady and (in certain years) Clouded Yellow can often be seen in late summer, along with the more common Peacock, Comma, Meadow Brown and Red Admiral butterflies.

Below is a list of the 27 species of butterfly that I have recorded in the Royston area since 2006:

Small Skipper, Green-veined White, Holly Blue, Speckled Wood, Essex Skipper, Orange-tip, Red Admiral, Marbled White, Large Skipper, Small Copper, Painted Lady, Gatekeeper, Clouded Yellow, Brown Argus, Small Tortoiseshell, Meadow Brown, Brimstone, Common Blue, Peacock, Ringlet, Large White, Chalkhill Blue, Comma, Small Heath, Small White, White-letter Hairstreak and Dark Green Fritillary.