Girton Birdwatch - November 2010
At the end of September I took a trip to the Wirral, Cheshire, and ended up at a RSPB reserve at Ness Marshes overlooking the Dee estuary and Welsh hills. Quite fortuitously the reserve was humming with visitors as it was playing host to two rare(ish) terns; the Black Tern and the much rarer Whiskered Tern. The latter, unfortunately for me, was off prospecting further along the coast so I missed out on that, but managed prolonged views of the Black Tern (not that it's particularly black at this time of year). I returned to Girton quite prepared to engage in some birding one-upmanship only to learn that 200 of these delicate birds had recently spent the night at Grafham Water before moving on south, an occurrence quite rightly described on the Cambridgeshire Bird Club's website as 'momentous'.
The Latin name for the bird is Chlidonias niger which apparently is a misspelling of the Greek Khelidonios - 'of, or like, a swallow' - a reference to its graceful flight as it hovers and skims over water picking up insects and crustaceans. We tend to think of terns as being birds of the sea and sea shore (our modern love of seaside holidays has, incidentally, largely evicted the beach-nesting Little Tern from its breeding areas) but, unlike their other close relatives, they are more attracted to, and associated with, marshland and inland freshwater sites. Indeed, when the East Anglian Fens were more extensive, Black Terns could be found breeding in large numbers. To modern birders the description by Pennant writing in 1769 of 'vast flocks' which 'almost deafen with their clamours' strikes a hollow note, as they are now lost to us as a breeding bird except, perhaps, for an occasional success at sites such as the Ouse Washes. They make up one of a raft of British birds - Spoonbill, Ruff, Black-Tailed Godwit, Common Crane come to mind - pushed to the verge of extinction through loss of wetland habitat.
Most of the birds we see are on migration (May-June), with more in autumn, when, like the one I observed, they are certainly not black. The spring passage birds are black, or rather dark grey with whitish under-wing coverts and a rather square tail. They look like large, dark swallows. In the autumn, as they head for tropical Africa, they are more uniformly light grey, with a blackish smudge on the shoulder. Perhaps with the proposed expansion of Wicken Fen - a nature reserve intended to cover around 53 square kilometres stretching from Wicken to Cambridge, and planned to be a 100 years in the making - we might see the restoration of this lovely bird as a British breeding species. (Ben Gibbs, a one-time resident of Girton, and son to Peter and Mary, has initiated a successful on-line petition in support of this project).
The 'Mediterranean' feel of the Wirral trip was prolonged on Sunday 3rd October as we sat in fierce sunlight in the garden of the Olive Tree caféOakington, and watched two Common Buzzards circling low over the adjacent trees. Apparently it's possible to see 4 or 5 at a time here, so there might yet be hope for the terns, and other threatened species, in the not-too-distant future.
When the sun wasn't shining, the wind was howling (only a slight exaggeration!), and led to the rare sight of Gannets in the area's skies. Even more unusual was the Great Grey Shrike which turned up at Fen Drayton Pits on 15th October. This is a relatively large bird - 25cms - and shares with the smaller Red-backed Shrike - 17cms - the nick-name 'butcher bird' after its habit of impaling its excess prey on thorns or barbed wire until required. Its diet not only includes insects, but small birds and reptiles, too. Stoats have even been taken. Most of the British birds originate in Scandinavia, although its population centre is the vast sub-arctic ranges of Russia which might hold as many as a million pairs.
It is fortunate for the shrike that it enjoys such a wide range of prey since the large insects which make up much of its summer diet are declining over most of Europe, given the intensification of agriculture and use of pesticides. The Great Grey Shrike employs a 'wait and watch' hunting strategy and requires a territory incorporating numerous high resting posts - its scientific name: 'excubitor' means 'sentinel' - from which it swoops and vertically pounces. 'Lanius', its generic name, tells us the rest as it's from the Latin verb lanio, meaning 'I tear or rend in pieces'.
As I type (20th Oct), waves of Fieldfares and Redwings have been sweeping in on the cold air, with hundreds spotted over Barhill, Fen Drayton and Cottenham, with more expected.