We have so far this year had mixed fortunes with our wildlife. A fine and often very hot early summer has had benefits that we did not see last year but there have also been losses. The saddest was that our House Martins failed to reappear to breed, and we probably now have to accept that our once thriving colony is now extinct. The number of occupied nests had been dwindling for a few years and was down to only one last year which really meant that there were not enough birds to replace losses on migration. The British Trust for Ornithology is monitoring this species but it is tempting to speculate whether we in our towns and cities are doing anything wrong. The problem may be that there are too few flying insects and it has been suggested that our well stocked gardens are using too many insecticides, successfully reducing greenfly from our roses but starving our breeding insect eaters. We have over the years lost Spotted Flycatchers and it should be noted that our much diminished urban House Sparrows feed their newly fledged young on insects rather than seeds. Having stocked a peanut feeder in my garden I am noting that the Blue and Great Tits are feeding more ravenously than in the winter and at a time when insect and caterpillar food should be readily available.
Swifts however did arrive, and clearly some have bred in the crevices of Victorian and Edwardian houses that they favour. These too have been the subject of anxiety as to whether the breeding population is being sustained. There did appear to be good enough numbers of feeding birds flying high but there was less evidence of the large screaming parties flying round our houses that we used to see and can still see in many European cities.
But of course there is also better news. Kestrels have once more bred in the tower of St Peter’s church at the entrance to Cox’s walk and fledged three young. Hobbys are probably breeding in the woods although the nest has not been found. There are probably up to five pairs of Tawny Owls nesting in our stretch of the Great North Wood. A singing male Firecrest was heard in Sydenham Hill wood in May which can identify it as breeding here, a first breeding record for Dulwich. A Brown Long eared Bat has been seen flying near the Cox’s Walk bridge where of course there is a population of Pipistrelles..
Emma Pooley, a university graduate who lives in Streatham has been appointed the London Wildlife Trust new Hedgehog Officer started work in August. She will be mapping the distribution of our residual hedgehog populations with a view to creating corridors whereby they might interbreed. We know that there are hedgehogs in the woods, in the Rosendale allotments and Horniman Gardens but she will be anxious to receive records wherever they are seen. It should be noted that slug killer pellets are toxic to hedgehogs, slugs being an important item of their diet, so gardeners should be encouraged to keep the use of pellets to a minimum if they know they have Hedgehogs.
After two poor years for butterflies this year is generally proving to have produced a marked recovery with greater numbers of Gatekeepers, Speckled Woods and Skippers and the new appearance locally of Ringlets. More spectacular, we again have Silver Washed Fritillary in the Sydenham Hill Wood. The more colourful Tortoiseshells, Peacocks and Commas put in an appearance early on but as at the time of writing we are between broods we will need to see how many emerge in the later summer. We may not however see the numbers that we were used to in years gone by as there is increasing evidence of decline in urban butterfly populations of these species, probably due in part to loss of breeding habitat. Indeed, because of their visibility, butterfly populations may be a marker for other less visible insects and the survival of our insectivorous birds.
None of these butterflies are yet particularly rare but we do have one that is the subject of much more interest to etymologists on account of its relative rarity and this is the White Letter Hairstreak. This is a small dark butterfly, not easy to see as it tends to fly in the canopy of trees and is so named after a wing marking in the shape of a W. It has become red listed as rare and endangered as its caterpillar food plant is Elm, trees that were decimated some years ago by Dutch Elm disease. I have been in touch with Mr. Bill Downey who is the National Butterfly Conservation transect coordinator for Surrey and south west London who has highlighted the White Letter Hairstreak as a key species for conservation. He has found the butterfly, during its flight period in June, in and around elm on Dulwich Common and also that part of College Road which adjoins Gallery Road, where there is a considerable amount of hybrid elm that is relatively disease resistant. He will be monitoring the species on behalf of the DEFRA UK National Biodiversity Plan who sponsor the National Butterfly Conservation scheme on an annual basis but it will of course behove us to identify and preserve the trees on which the butterfly depends.
We in Dulwich are blest with our green spaces, woods and parks but for the preservation of our wildlife there is a lot to consider when we see our well kept gardens devoid of the butterflies we expect to see visiting our scented flowers.
Peter Roseveare Wildlife Recorder (tel: 020 7274 4567)