Girton Birdwatch - December 2011
I've mentioned before how pleasing I find the increase in the common buzzard population which has occurred in recent years. Over the past few weeks I've taken to walking the dog across the fields and down the guided busway to Westwick and a day seldom passes when I don't get good views of this once uncommon bird or, at the very least, hear its cat-like mewing call. I read somewhere recently that it is now more numerous than the kestrel. Not everyone likes the buzzard. In the past it had a rather ambiguous moral image and was compared unfavourably to the noble golden eagle (with which it was often confused, hence giving rise to one of its folk names: 'Tourists Eagle'). Thomas Bewick, the great 18th/19th century wood-block engraver described it thus: 'Though possessed of strength, agility and weapons to defend themselves, they are cowardly and inactive; they will fly before a Sparrowhawk, and when overtaken, will suffer themselves to be beaten, and even brought to the ground, without resistance'. Men of a certain age are still often referred to, unflatteringly, as 'old buzzards' or even 'ornery old buzzards'. In Hollywood western films of a particular vintage the sight of buzzards circling in the sky invariably meant that a human corpse lay near by or that the apache indians had massacred a wagon train of unfortunates. The fact that these carrion-eating 'buzzards' were really turkey vultures, and extremely ugly to boot, did little to save the buzzard from opprobrium. Nowadays, the buzzard is a more welcome sight - although not, perhaps to some game-keepers - and more likely to evoke feelings of admiration for its aerial abilities and its tendency to conjure up mental pictures of the wild and beautiful areas of our country.
It was not, however, the ubiquity of the common buzzard that prompted these observations but the recent sightings throughout the county of its cousin: the rough-legged buzzard. This scarce winter visitor to Britain is a touch more impressive than its more familiar relative, not only because of its greater size but because it summons up images of its tundra breeding grounds beyond the Arctic Circle. It is usually paler than the common buzzard and has longer wings; its tail is white with a dark terminal band. It hovers much more frequently and ably than the buzzard. Its name derives from the fact that its legs are feathered to the toes, although these may be difficult to see.
Most birds that reach Britain in an ordinary winter remain close to the east coast in East Anglia or Kent. The relatively large numbers that we are now experiencing are probably related to the rodent cycles that have an influence on breeding success. Good spring lemming or vole populations in Scandinavia and Finland can lead to large clutches and, if the rodents continue to breed through the summer, the large clutches become successful broods. This is when more rough-legged buzzards are likely to reach Britain, although the main movement is south to south-east, taking birds to the Black Sea and Caucasus.
One of the best rough-legged buzzard winters was 1966-67 when there were 67 records. This, however, was attributed more to a crash in vole numbers than to an unusually high rough-legged buzzard population. 1974 was even better, when the wintering population probably exceeded 100 birds, with many more being seen in passage in October.
It is probably more than coincidental that the region is also playing host to more than normally high numbers of short-eared owls this year, because a good supply of small rodents is the main factor controlling the distribution of this bird too. I don't know whether voles have had a particularly good year hereabouts but in the past, before the widespread use of lethal rodenticides, plagues of voles used to occur which were capable of reducing grasslands to virtual deserts. However, the abundance of voles led in turn to vast influxes of short-eared owls which quickly got the problem under control. In southern Scotland during such a plague, at the end of the 19th century, it was possible to travel for miles on end while still keeping at least a dozen short-eared owls in sight at any one time.
This is a bird that you are quite likely to catch a glimpse of - although the only one I've ever seen passed high over our house a couple of years ago - as it is largely diurnal (flying during the day as well as dusk and dawn) and also has wings which are astonishingly long for the size of the bird. It looks like an owl, but like no owl you've ever seen before! It breeds in this country but mainly north of a line between the Humber and Mersey estuaries, but they are capable of sustained journeys and routinely migrate from continental Europe in late autumn when they can turn up on downland, heath, reed-beds or coastal dunes. The short ears which give it its name (they are not ears but merely tufts of feathers) are usually invisible but the face, buff white with black rings surrounding staring yellow eyes, is striking enough in its own right.