Nature notes: Is the butterfly on the decline in Cambs?
Summer brings out the butterflies. Or does it? Have you seen any in your garden, and if so, then which species? Chris Packham recently reported not finding any in his garden and it does sometimes seem that there are fewer around than in bygone years. So what are the facts? There have certainly been declines in many of our once familiar species, but also a few, including red admiral and comma, that have bucked this trend and become commoner.
According to the latest annual survey, last year was one of the worst on record for butterfly populations in the UK with many of our 59 native species showing marked declines. Like many insects, butterflies face multiple challenges, notably habitat loss, pesticides, pollution, and also climate change. While our weather is getting warmer on average, it is also becoming more unpredictable, which disturbs the natural cycles of butterflies. In towns and cities, nitrogen pollution from exhaust fumes has led to local declines in butterflies, making the value of green spaces such as gardens, parks and allotments more and more vital for their survival.
This month I have not seen many in our garden, except a handful of holly blues and the occasional white, and even a small heath that turned up recently – a first for our small green patch, and a pleasant surprise. Down on the allotment there are more butterflies about, probably because the habitats are much richer and more varied, with weedy areas of nettles, comfrey and brambles bordering many of the cultivated plots and providing food for the larvae of some species such as red admiral, peacock, small tortoiseshell and comma.
Though some species can be a nuisance, such as large, small and green-veined whites whose larvae feed on members of the cabbage family (including cabbages and other cultivated relatives), and also have a taste for nasturtiums, most butterflies are harmless to our vegetables and garden plants, and bring us nothing but pleasure. Maybe the decline in large white numbers is even welcomed by some gardeners and farmers, though I hate to see any of our species reduced.
The comma is one of my favourites. Bright orange on the upperside with characteristically jagged wing margins, and highly camouflaged beneath, with a tell-tale white mark, rather like a comma punctuation mark. Commas lay their eggs on stinging nettles and also on hops. A century ago this feisty species was on the brink of extinction, but is now common in southern Britain.
Another charming butterfly showing now is the speckled wood. Dark brown and speckled with creamy-white spots it often flies in dappled shade and the males are highly territorial, chasing off any intruders. The larvae feed on several species of grass. Like the comma, it is mainly a southern species. The males like to rest in a patch of sunlight, while the females usually stay in the treetops.
One of our larger common species is the boldly-marked red admiral. Its wings above have bright orange-red bands set against a dark background and black tips splashed with patches of pure white – an impressive insect indeed! It is worth encouraging a patch of nettles for this insect alone. Most red admirals arrive each spring and summer as migrants from further south in Europe, though some may hibernate through our winters.
The small tortoiseshell is highly colourful – orange and brown, with black blotches and circlets of blue dots around the wing margins. They lay on nettles but are extremely fussy about which plants to choose, selecting mainly young shoots and leaves in sunny positions. A damp patch of mature nettles in the shade is unlikely to appeal.
Surely one of the prettiest of our early summer butterflies is the orange tip. The male is very easy to identify. It is small and white, with a bright orange tip to each forewing. The female could be mistaken for a white as she lacks the orange tips. Both sexes are beautifully patterned below, with green dappling on the hindwings. The main larval food plants are lady’s smock and garlic mustard.