I am writing this in mid-February during the second heavy snowfall of the winter. It seems that this winter is more like the winters I remember as a boy. The 1962/63 winter is one that I will never forget; my bed at school was nearest a door which led directly to the outside and wasn’t very draught-proof! In 1962/63 the smaller birds, such as the Wren, suffered population crashes by as much as 90%. Fortunately these birds have large brood sizes and can regain their former numbers within a few years. Another bird that suffered dramatic losses that winter was the Dartford Warbler (first identified in 1787 on Bexley Heath nr Dartford) when only eleven pairs were found the following summer along the Hampshire Dorset Coast. Over the years it has recolonised all its former range and had even appeared as far North as South Yorkshire. It particularly likes heath lands such as the sandy ones found in Surrey and Sussex. In 2001/2 it made a brief appearance in Hemsted Forest where it attempted to breed without success and eventually moved elsewhere. Last winter was the coldest winter for 12 years and it appears from the latest reports that Dartford Warblers numbers have crashed by over 80%. They predominately survive in the winter by feeding on spiders and therefore particularly favour mature gorse bushes where they find protection from the weather and colonies of over-wintering spiders. I would imagine that this winter, being even colder than last winter, will reduce the number of breeding pairs next spring to nearer the post 1962/63 figure. The other casualty from last winter was the Goldcrest, our smallest bird, with reporting rates at about half the previous year’s level. These small birds have to find food equivalent to 20 to 30% of their body weight every day just to survive and it is not surprising that their numbers drop in cold winters. Fortunately, once again they have large clutch sizes of ten eggs (which weigh in total 1.5 times that of the parent bird) so their numbers can climb quickly again. The other species notorious for declining in hard winters is the Cetti’s Warbler, although from my personal observations it seemed largely to have survived last winter, but will it do so this one? The Cetti’s Warbler enjoys a very different habitat from that of the Dartford Warbler. It likes wet scrubland in a reed marsh habitat.

I mentioned the Wren as being vulnerable to cold winters and the low number of Wrens I am finding in my winter surveys already concerns me. Last year during a typical 2-hour survey I would log between 3 to 7 birds; this winter particularly in the last few days, it is only 1 or 2.

With our so-called milder winters some of our summer visitors over-winter here rather than migrate south. Chiffchaff and Blackcap are by far and away the most frequent. Rather strangely I have seen more Chiffchaffs this winter than usual. They are insect eaters and in the winter they frequent watery habitats where they feed on midges etc. It is not surprising that the three Chiffchaffs that I have found this winter have all been near a sewage farm. During the cold weather one of my surveys took me past the Tenterden sewage farm and on the filtration beds I counted twelve Pied Wagtails, seven Meadow Pipits and two Chiffchaffs. A few days later I was in Devon staying in a small village with a sewage farm about one-twentieth of the size of the Tenterden one. A Chiffchaff, Wren, Pied Wagtail and a Blackcap were all catching insects nearby. The Blackcap broke into song, which alerted me to its presence in the first place. Ringing recoveries of Blackcap in particular demonstrate that the birds that winter here do not breed here but come to us from Eastern Europe whilst our breeding population migrate to the Med. I am wondering, though, that because this one broke into song, might it be one of ours and not a migrant? The migrants do not normally sing until back at their breeding grounds.