Autumn has come rather suddenly this year with a deluge in late September after long dry spells over the summer. The summer visitors have largely departed except for a few lingering Chiffchaffs that often join the Autumn feeding flocks of Great, Blue and Long Tailed Tits. Although they can be mostly detected by their high tweet call, a few will restart their chiffchaff breeding song perhaps stimulated by the similarity of the September day length to that of Spring. Apart from their song they are virtually indistinguishable in the field from Willow Warblers, which although they do not breed in Dulwich do pass through on migration, again giving a little of their much more musical Autumn song. Autumn passage migrants can afford a little more time to hang around than in Spring and Willow Warblers have been heard in Belair and Dulwich Parks and this year also Spotted Flycatchers in Brockwell Park, an increasingly unusual record for a bird that used to breed here.
A Kingfisher has been seen in Dulwich Park, probably a young bird, part of an Autumn dispersal from parental territory. Kingfishers do breed on the River Waddon, not far from us but are unlikely to set up territory here as they prefer running water and need lots of little fish. Autumn Kingfishers have appeared before and one was photographed in a Burbage Road garden some years ago. A Raven has been spotted flying over Dulwich woods on 15 October to the annoyance of the Carrion Crows. This was a first for us, but they have been expanding their range eastwards from their strongholds in the south west so it was probably not an escape from the Tower of London, which if the legend is correct would foreshadow apocalypse.
Dave Clark has provided his regular Dulwich Park bird count. A huge number of 461 Wood Pigeons were probably inflated by an early influx of continental migrants and our winter Shoveler ducks have arrived early. Some of his figures over the years such as Robins, Wrens, Tits and Blackbirds are very consistent and there is an increasing number of Jackdaws, but things look less good for Song Thrushes, Greenfinches and Chaffinches.
This year the British Trust for Ornithology have set up a survey to assess the status of Tawny Owls. This is particularly difficult as they are strictly nocturnal and mostly in woodland. So they have to be counted by call (Too Whit if female and Too Whoo if male). Unfortunately, if they don’t call they don’t get counted so observers need patience. We have always had Tawny Owls here and young Tawny Owls were heard calling in the woods this summer proving successful breeding. The young while still downy emerge early from their nest holes in what is known as branching to sit and receive food from their parents. The accompanying photograph taken by my grandson Matthew in the New Forest illustrates this wonderfully well.
2019 has been a “butterfly year”, distinguished by the arrival of Painted Ladies, Red Admirals and also a day flying moth, the Silver Y from as far away as North Africa. They probably arrive on southerly winds after some bumper breeding success on the continent and a number were seen here although they were more abundant in southern coastal counties. Of interest is the question as to whether they fly back, the assumption being that they come here and perish as soon as the weather deteriorates. The surprise is that the evidence is that they do and that shortening day length stimulates southerly directed flight and lengthening days stimulate flight northward. Radar tracking has shown that in the Autumn southerly migration Painted Ladies can cover 5,000 miles in a single generation to take them as far as the Sahara Desert. Nature can continue to surprise us.
Out of town our native butterflies have mounted a recovery after bad years. In Dulwich this has yet to become obvious and we still have not achieved abundance of Peacocks, Tortoiseshell and Commas. Our many Oak trees however do give a variety of other invertebrate life amongst which is the Oak Bush Cricket that looks like an outsize green grasshopper which surprised John Hughes when it appeared offsite in Winterbrook Road. Unlike Grasshoppers, Crickets can wander and one may turn up quite harmlessly in your home and if so it should be humanely returned to its normal habitat.
In the last issue of the journal Charles Newman wrote of the changes in our local bird populations he has observed over the twenty years he has lived here, outlining some of the losses and gains. Clearly there are changes in our urban birdlife not all of which carry a ready explanation. Why for instance have we lost so many of our Song Thrushes when our gardens are awash with snails, their favoured food? Why are Blackbirds and Robins doing better? What has happened to so many of our Starlings? There are almost certainly many factors as each species will have its particular problems amongst which is the availability of favoured invertebrate food, not the problem for the Song Thrush. But some of the birds that are doing particularly well are the opportunistic scavengers that can double up as nest predators. The key to the success of Magpies, Carrion Crows and indeed the newly arrived Jackdaws is their ability to learn to overcome their instinctive fear of the human race, and this matters in our increasingly crowded urban environment where they can live off our produce and waste. With nest predation their success may tip the balance between them and birds less well adapted to us such as the shy Song Thrush. This is perhaps one of a number of reasons why we are observing losses of some well loved species about which there may not be a lot we can do. But one thing we can say is that much of our wildlife need protected space with suitable cover to live and breed which we should try and make more available around us.
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