Since moving into our house in January 2012 I’ve been keeping a list of butterflies and day-flying moths seen in the garden (as well as birds and bees, of course). That list currently contains 14 species*, one of the most interesting of which is the Gatekeeper (Pyronia tithonus).
According to the account of this species on the UK Butterflies web site, the Gatekeeper:
“can be found wherever shrubs grow close to rough grassland. ……some of the largest colonies can be found at field edges and along hedgerows and we can expect to find this butterfly in scrubby grassland, woodland rides, country lanes, hedgerows and the like anywhere within its range”.
So what is it doing in an urban garden? The BTO’s summary of the species mentions that:
“It is rare for Gatekeepers to appear in city-centre gardens. However, in recent years this species has been recorded at some urban sites across north-east London and Hampstead Heath and, more recently, on Wimbledon and Mitcham Commons. Such range expansion into urban areas may be due in part to changes in the management of urban parks and cemeteries”.
Clearly, in order to exist in an urban setting the Gatekeeper must have its basic requirements met by the habitat in which it finds itself. As I’ve mentioned before, the lawn in our garden is quite diverse and contains a number of native species, including a range of grasses that could be used as food plants by the caterpillars, though we do keep it quite short. It’s more likely that the caterpillars are feeding in some of our neighbouring gardens, which are rarely troubled by a mower (do neglected gardens host more biodiversity than highly managed gardens? I suppose it depends on the type of management; would be an interesting question to research).
As well as the larval food plants required by Gatekeepers, there’s a range of nectar sources available in a mixed native/introduced hedge along the northwest boundary, including the bramble I recently discussed, oval-leafed privet (Ligustrum ovalifolium), and the buddleia (Buddleja davidii var.) seen in these photographs.
It will be interesting to see if this colony persists over time (I also recorded the species in 2013 but not in 2012). I get the impression that there’s only a small number of individuals, though it’s difficult to assess the population size of butterflies without catching and marking individuals, which I plan to do next year. It’s a lovely species and we’re fortunate that it likes our garden. I’d be very interested to hear from any other urban gardeners who have seen it in their patch.
*Large White, Speckled Wood, Small White, Holly Blue, Red Admiral, Cinnabar, Large Skipper, Meadow Brown, Peacock, Gatekeeper, Comma, Brimstone, Orange Tip, Small Tortoiseshell.