The latest report from Michael Walter:
The territory maps have now been drawn up, so we can see how many birds of each species there were this spring, and compare the results to last year - and what dismal reading it makes! Wren, nightingale, garden warbler and spotted flycatcher have all performed very poorly, and some others, while not far below the long-term average, have been present in much lower numbers than last year. Small birds suffer disproportionately in cold winters, such as the one we’ve just had, made worse by the freezing rain at the beginning of March that covered everything in a layer of ice, locking away all the insects on which wrens depend. The other three species I mentioned are all long-distance migrants, which are suffering from drought and habitat destruction in Africa as farmers move into semi-natural habitats in a bid to feed a burgeoning human population. Saddest of all is the decline of the willow warbler, once one of our commoner species; now, as the graph shows, it is heading for local extinction, and in a few years its beautiful, lilting cadence may no longer be heard on spring mornings. Interestingly, its widespread decline in England in recent years has been balanced by a marked increase in Scotland, lending force to the argument that warmer and hotter summers in the south are rendering their habitat unsuitable: we ignore climate change at our peril. Almost as sad is the near demise of the spotted flycatcher: although never common at Blean, there was a reasonably healthy population in the 1980s, but numbers collapsed in the late 1990s, and failed to recover subsequently. This year I had just two records of these unobtrusive birds (neither of which necessarily stayed to breed), and that was it. The good news is that three of our rarest butterflies have enjoyed their best season for some years. The heath fritillary had been in the doldrums since 2011, but this year numbers rocketed at many of its colonies, the butterflies often too numerous to count accurately. Two other species that had died out in the woods during the 1950s, the white admiral and silver-washed fritillary, have been attempting to get re-established in the past six years, and they at last seem to have gained a firm foothold, although it remains to be seen whether that will translate into healthy future populations.