Where Have All The Blackbirds Gone?
This was the question I asked myself as October progressed when I realized that I had not seen a Blackbird in my garden since mid-summer. Several walks around Dulwich and Belair parks were just as unproductive. Dave Clark has now done his regular, more systematic autumn bird censuses in Dulwich Park and Sydenham Hill woods and reports less than half the usual numbers of Blackbirds and a general reduction in the numbers of all small birds with the exception of Goldfinches that we have previously noted to be thriving. Surprisingly he also notes that in particular there was a dearth of the usually common Blue Tits, and I notice that Blue Tits around here are much outnumbered by Great Tits and even Long Tailed Tits. Happily, on a very wet late October day Blackbirds have returned to take advantage of our berry laden Hawthorn and recently tilled ground. But this is the time of our winter arrival of continental Thrushes including of course flocks of Redwings which are indeed in evidence this week. Blackbirds are part of this movement so our new arrivals may well be passage migrants rather than our home bred population.
What are we to make of all this? The glaring answer is that unfortunately the much discussed climate change is beginning to kick in to our familiar wildlife populations and it is not just the winters but our summers that have become the problem. This year we witnessed a drought that extended from April through the whole of May. For most of us the fine weather made the rigours of the Covid lockdown bearable, but it dried the soil at just the moment when ground foraging birds needed access to invertebrates to feed their nestlings. In some cases it leads to smaller clutch sizes and in others to nestling starvation and our Blue Tits also needed their hatch to match micro moth caterpillar emergence. Most of our small birds have short life spans and need an annual survival of at least two nestlings to maintain their population numbers. It is therefore not hard to see how quickly an imbalance of our natural history can take effect.
So what can we do about it when we are such a small oasis in a global phenomenon? For the problems I have highlighted an answer may be the provision of summer feeding. A clue may lie in the rise in Goldfinch numbers that provides one of the bright spots both locally and nationally and this has been directly attributed to their adaptation to their use of feeders and particularly Niger seeds. Supplies of mealworms could well compensate for dried out soils and peanut and seed feeders can maintain the health of Tits while they forage for caterpillars to feed hungry nestlings. This could be just a small step in the combat of a global trend which is responsible for so many of our wildlife losses that I have reported in this column over the years.
On a different tack there is still plenty of wildlife to observe. Some but not all Egyptian Geese, have bred successfully and have become a permanent feature of Dulwich Park, welcomed as a decorative replacement for the ubiquitous Canada Geese. Cormorants are regularly visiting and appear to be fishing for the introduced Carp. The Herons appear usually to be at rest but maybe they too could have a go. The accompanying photograph was taken by Mary Elizabeth Everitt and her friend who were surprised on a walk down College Road by this very close female Sparrow Hawk that did not wish to relinquish her prey in spite of their proximity.
As to other wildlife it has been a mixed year for butterflies. The hope that the encouraging spring emergence of Peacocks, Commas and Tortoiseshells from hibernation would be succeeded by a big mid-summer population was not realized although a few were present. It was a good year for Holly Blues and there were good numbers of Common Blues, Gatekeepers and Small Skippers in the Velodrome site and also a few Small Coppers. The spectacular Jersey Tiger moths, camouflaged at rest but a brilliant russet orange in flight continued to attract attention and I was surprised to record a Five Spot Burnet moth in my garden that I had not seen there before. Once more this year fine evenings provided records of Stag beetles. These are of course the high visible end of the insect population but a detailed knowledge of the great mass of insects that provide the bed rock of the nutrition of our vertebrates will require more study if we are to understand how to conserve our natural environment.
Do please keep me supplied with your records and observations. I have been glad to hear that the Bats that were identified last year have continued but it would be good to know how Hedgehogs have fared.
Society Talks - December 10th 8.00pm
Peter Roseveare, the Society's wildlife recorder, will speak on "Wild Dulwich Through the Seasons". This is the 5th in the Autumn series of our online talks and promises to be one of interest to everyone, covering the wide range of wildlife we can see in Dulwich, along with many interesting anecdotes he can report from his many years as our recorder. As with the other online talks it will be via Zoom.
Joining details are: https://zoom.us/j/96970847928
Meeting ID: 969 7084 7928
We are hoping to run a similar series of talks in the Spring. These will be advertised via the eNewsletter and journal.