Saturday, 15 February 2014

Spring is nearly here

This last week's storms have rather taken attention away from what ought to be time of renewed hope. The yellow crocuses are in full bloom, as are the pale purple early spring crocus and snowdrops. In the urban garden there is probably more for hoverflies to find nectar and pollen sources than in the countryside. I rarely see anything at hazel catkins, but then I probably don't spend enough time looking!

What really struck me, however, was how the spring garden has changed in the last 40 years. When I was growing up in London in the 1960s and '70s our garden was often filled with the excited chatter of a flock of house sparrows. Those same house sparrows used to descend on the crocuses and tear them to pieces, so one of the first winter jobs for my mother was to create a latticework of cotton over the flowers to keep the marauding birds at bay. I cannot remember when we last had to do this in my mother's London garden. Today, the garden is silent - the sparrows are gone.

The house sparrow is in many ways just part of the story. In winter months we were also treated to the amazing spectacle of millions of starlings streaming out of London towards their roosting grounds in the hawthorn copses of Mitcham Common. They used to turn the sky almost black just before dusk. The hawthorn thickets were often white with starling droppings. Again, the spectacle is gone, but the starlings' legacy lives on because the most favoured woodland roosts have a very different ground cover - each former tree (now largely dead and overtopped by oaks) is represented by a ring of nettles and elderberry. It is an important reminder just how important birds can be in nutrient cycling and also how environments can be subtly changed by a passing phase. This sort of impact is worth remembering because it can help in interpreting the evolution of the landscape.

What we have in place of the sparrows and starlings is a huge flock of ring-necked parakeets that roost in a poplar plantation on Mitcham Common. There can be several thousand on a good night. I would much prefer the starlings and sparrows as these noisy replacements fill the air with squawking that can be really quite a distraction.

The carrion crows of London now descend on the common too; they never did this when I was a boy. On the one occasion I made an effort to count them I noted nearly 600 birds assembling in the poplars along the railway line adjacent to the Croydon Road. The crows then descend upon the Golf course where I assume they spend the night. It is a very different but still an amazing spectacle. Quite what it tells us about the ways in which the ecology of London is changing I am not sure. Crows used to breed in the big poplars and their old nests were subsequently used by kestrels. The poplar trees were blown over in old age and have yet to be fully replaced by the younger plantations. The kestrels have gone too. So have skylarks, reed buntings and stonechats; and linnets, goldfinches, greenfinches and bullfinches are considerably rarer. We do, however, have a magnificent flock of Canada geese that are changing the ecology of the Severn Islands Pond and the surrounding acid grasslands. There is also a delightful pair of Egyptian geese that has successfully bred.

So, I hear you say 'what does this have to do with hoverflies?' Perhaps nothing; but then again, had I not gone into the garden to look for hoverflies I might not have recalled the mischievous chatter of the house sparrows and the changes that have happened in the passing of just 40 years! In many ways, this is a metaphor for all those other changes that have happened, that perhaps the less observant or interested do not notice.

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