Wednesday, 8 October 2014

Kestrel no longer so commonplace

Writing in early 1917 and far from home, the poet Edward Thomas noted how the sight of four or five planes ‘weaving and wheeling overhead’ reminded him of the kestrels that he used to see over the Shoulder of Mutton Hill near Petersfield. Such recollections rekindle my own memories of days spent near Petersfield and of the kestrels that would haunt the skies, scanning the ground below for small mammal prey.

Throughout my childhood the kestrel was regarded as our most commonly seen bird of prey, a familiar species that I was certain to see from a car journey of any distance. Long-term monitoring data from the British Trust for Ornithology (BTO) support this, showing the kestrel population of the mid-1970s to have recovered from the effects of organochlorine pesticides and to be at a peak not since matched. This peak was, however, short-lived and there was a substantial decline over the following decade, which left numbers well below the level that had been achieved. This new decline has been driven by a period of agricultural intensification that left our farmland much changed. The loss of many thousands of miles of hedgerows and field margins brought about a decline in the numbers of small mammals and large invertebrates upon which our kestrels depend.

We are not alone in having lost so many kestrels; it is a pattern repeated more widely across Western Europe, underlining how the changing demands we have for cheap food, produced in ever increasing quantities, have changed the landscape fundamentally. With less space for wildlife it is inevitable that those species at the top of the food chain will show pronounced changes in their numbers and abundance. The pattern of change seen in our kestrel populations shows some regional variation; for example, the species benefited during the period of afforestation, where many hundreds of hectares of coniferous plantation were established. However, as these new forests developed so they shaded out the swards of rough grassland between their ranks and with this loss went the field voles and their kestrel predators. The kestrel remains common enough to remain familiar and to haunt the texts of today’s nature writers. Let’s hope it remains a living part of our countryside and not one consigned to our literary heritage.

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