Girton Birdwatch - October 2008
September and October are exciting and interesting months for birds as so many are on the move; birds are leaving, more are arriving, others are passing overhead or moving within the British Isles, while still more are being blown off course by inclement weather conditions. American, Siberian and Continental European birds will be turning up all over the country while many of our winter visitors will be making their presence felt from mid-September onwards, with Redwing, Fieldfare, Brambling and Siskin all returning over the next few weeks. Experienced birders will be sky-watching during September/October and keeping their ears open at night for the large flocks of 'fly-overs'. My hearing is no longer up to the task but it should be possible to hear the slightly sad, Coal Tit-like call of passing Siskin, or the 'dweep' of Brambling, while September and October are ideal times to listen at night for the thin 'seep' of over-flying Redwing. It will soon be difficult to miss the grey and chestnut plumage of the Fieldfare even if you're not alerted to its distinctive 'chack chack' call. You might even be as lucky as Jonathon Heath who at Milton Country Park recently, not only heard a Wood Pipit (a difficult bird to encounter at the best of times) but was also able to snatch a lovely photograph of a passing juvenile Osprey. This may be seen on the Cambridgeshire Bird Club's website at www.cambridgebirdclub.org.uk if you're interested. Lots of Wheatear, Whinchat, Spotted Flycatchers and Yellow Wagtails have also been passing through the county, plus the occasional Redstart, Crane and Spoonbill. On the 9th September, moreover, a Wryneck was in a west Cambridge garden. I was intrigued to read recently that although most British Blackcaps migrate for the winter to Spain and Africa, many other Blackcaps come to Britain from Germany and the Low Countries, giving the impression that more of our 'summer' Blackcaps are staying for the winter than may in fact be the case.
Probably one of the more exciting developments locally over recent weeks has been the sighting of large numbers of Honey Buzzards. In September birds were seen at Ely (3), Little Paxton, St. Neots, Buckden Gravel Pits, Ferry Meadows, Wicken Fen, Witcham, Melbourn and Royston. Honey Buzzards tend to fly very high at this time of year - indeed this is a bird which is almost always only seen in flight or migrating - but, given their unusual or distinctive silhouette, it should be possible to make a positive identification if you are fortunate enough to have one pass over near you. They are, believe it or not, Buzzard-sized (about 55cm - 21 inches) but the bird is badly named for it is neither a Buzzard nor does it eat honey! It is slimmer than the Common Buzzard with longer wings and longer tail. It has a narrower neck and a Cuckoo or pigeon-like projecting head. Although its plumage is variable (like the Buzzard) the upperside is usually a dark brown, while its underside is pale, almost white, sometimes having thin near-horizontal stripes of brown from body to wing-tips. Its long narrow tail possesses one or two clear dark bands and a black tip.
In Britain the Honey Buzzard is probably limited both by habitat and by its eating habits. It favours large tracts of mixed woodland with natural glades - normally ruling out much of this region - where it can hunt its prey, wasp nests. It relies almost entirely on the grubs of wasps and bumble bees, with an occasional frog or lizard thrown in for variety. When eating the wasps' nests and grubs some of the comb is also consumed, which some authorities believe acts as roughage, and it also eats a few birds; however it cannot live and breed unless it can find enough wasps' nests. One estimate has it that a pair of Honey Buzzards with a brood needs 90,000 wasp grubs per year - now that's what I call a bird with redeeming social importance! The bird is also anatomically adapted to this specialized diet. Because it does not kill large animals or birds it doesn't need sharp talons so its claws are blunt and nearly straight, like those of a domestic hen. A foot like this is much more suitable and efficient for walking on the ground and digging than would be a foot with long curved talons. Next time you see an eagle, either in the wild or on television, notice how awkward it is when walking. The Honey Buzzard's face, which is bare in most birds of prey, is covered with stiff, short, scale-like feathers which some people assumed were there to protect it from wasp stings. However, although a feeding bird is certainly not popular with angry wasps they do not attempt to sting it but hover impotently around its head and may, in fact, be caught and eaten with impunity. Other animals or humans may not be so lucky in avoiding the disturbed wasps or bees and could be attacked. Some brave or fool-hardy birders have apparently been alerted to the presence of a feeding Honey Buzzard after having been so surprisingly and unreasonably attacked. Don't try this at home!