Girton Birdwatch - July 2010
I would like to dedicate this month's Birdwatch to Bob Benton who died on 28th May, aged 73. Bob was, in the words of his obituary, 'a decent, kind, gentle, helpful man' with a great love and knowledge of wildlife. He was also one of my main sources of information about the birds visiting the village and its environs. I shall miss him greatly. It is ironic and fitting that I always intended to devote this edition - June being a quiet month for birds - to a piece of intelligence provided by Bob about a rare mammal which has apparently set up residence down Washpit Lane: the water vole.
The water vole has received a great deal of publicity recently, mainly because it is one of our most threatened wild creatures. At one time it was a very sight in the British countryside but its population has undergone one of the fastest and most serious declines of any British mammal. A national survey in 1996 to 1998 showed that the water vole had been lost from a massive 94% of sites and had vanished from entire catchment areas in northwest Scotland, North Yorkshire and Oxfordshire. In East Anglia one of the great threats to the water vole came from the escape into our waterways of the South American coypu, which was introduced into this country between the wars by fur-farmers. This huge rodent, which was able to climb wire netting as high as eight feet, to burrow long distances into banks, and to bite its way through wire netting with its powerful teeth, proved to be an inveterate escaper and was soon well-established in the wild, where it destroyed river banks, munched its way through aquatic vegetation and generally thoroughly out-competed the water vole. Moreover, while 70% of water voles fail to survive the winter and have very short lives, only living from 5 months to three years in the wild, the coypu was a prolific breeder and extremely hardy. The success of a government sponsored extermination programme - after early failure - has been partly responsible for a slight relative recovery of water voles in East Anglia recently.
The water vole, however, has many other natural and 'unnatural' enemies. It is taken by barn and tawny owls and other birds of prey, the heron, bittern, stoat, weasel, and pike, not to mention the domestic cat, foxes and adders. The great 'unnatural' threat, though, is the mink. The American mink, a relation of the stoat and weasel, was introduced into Britain in 1929 and, like the coypu, soon escaped from the fur farms in which it was supposedly incarcerated. Animal rights protesters also deliberately released this savage killer into the wild, with all sorts of unintended consequences for the native fauna. The mink quickly proved itself to be a serious predator upon the water vole. Water voles, when threatened, tend to dive under the water and kick up clouds of mud amongst which they hide from their enemies. Unfortunately this provides little protection against the mink which is able successfully to hunt the water vole on land, in the water and even inside its burrow system. Wherever mink numbers are high, vole numbers tend to be low. It is unrealistic to expect the total elimination of the American mink but in areas where attempts have been made to control their numbers pressure on the water vole is eased. I wonder if anyone has seen mink around Girton? They are certainly in the Cam and the Granta but perhaps our local water courses are too modest for them?
Paradoxically, one threat to the water vole is the affection in which it is held and its starring role in that favourite book of childhood - at least among the pre-computer game generations - Kenneth Grahame's Wind in the Willows. 'Ratty' was not a rat but a water vole, but some authorities have suggested that this misleading name - and our general abhorrence of rats - may have led some people to attack and kill it. Water voles, unlike the brown rat, have a short hair-covered tail, a blunt rounded nose, and a small chubby face with small ears. Its coat is a rich chestnut brown, except in Scotland where some individuals often have black fur.
It was Bob, and later his wife Elizabeth also, who alerted me to the presence of another relative rarity down Washpit: the turtle dove. This summer visitor is one of our prettiest birds and is more attractively plumaged than the much more common interloper, the collared dove. Its plumage is rusty-brown, its wings are speckled, scaly brown, while there is a black and white patch on its neck. Its song has a soft, purring quality which, once learned, is unlikely to be forgotten. Unfortunately this contented 'purring' is no longer as commonly heard as it once was. It has suffered a more than 50% decrease in the last 25 years, putting it on the Red List of conservation concern. Turtle doves have long had to brave the Continental guns on their way here - not always being safe once arrived - but the shortage of weed seeds on the clean modern farm doesn't do them any favours either.
Down the road at Ouse Fen there's been another rarity: the Red-footed falcon. A handful of these elegant birds reach Britain each year and always cause a stir. They are like a small, dainty kestrel, feeding mainly on insects. The sexes are very different: the female has a rusty-orange to pale yellow crown and abdomen, in contrast to grey dark-barred upper parts; the male is all grey but with red under the tail. The adults both have red feet.
It's great to be able to say that there were two reports of red kites in the vicinity at the end of April and early June. Sandi Irvine and friends watched one circling low over Northfield on 29th April, while another was over the Oakington Garden Centre on 6th June. I can't get enough of these beautifully dramatic birds. Buzzards are living up to their name 'common' also, while a hobby patrols the Dry Drayton road most evenings.