Girton village website - Nature

Girton Birdwatch - March 2008

If golf can be described as 'A good walk ruined' what might we say about bird-watching at a sewage farm? I was encouraged to ask myself this question after leafing through an old book that I own, published in 1974, called 'Seventy years of Birdwatching' by H.G. Alexander. Here, Alexander, or 'H.G.' as he affectionately became known, not only itemises many of the birds to be found on a walk through the Grantchester area in the 1930's, but writes enthusiastically about the charms of the sewage farm, including the one then to be found at Cambridge. Indeed, he tells us that: 'The years between the two great wars might be described as the years of reservoirs and sewage farms, so far as British field ornithology is concerned.' Alexander was well-placed to chart the various developments in birdwatching as he began his hobby in 1898 and continued to pursue it until after his hundredth birthday; he died in 1989 at his adopted home in a Philadelphian suburb. During his lifetime the pastime he so enjoyed and did so much to encourage went from being a minority interest followed by a handful of eccentrics, to a mass participation activity engaged in by millions. Interestingly enough, when Alexander first developed his interest in birds, at the age of eight, he had to manage with his unaided eyesight as he lacked a decent pair of binoculars; he was twenty one before he acquired a pair of his own (previously sharing a battered pair with his brother). This was a period during which it was perfectly permissible, if not a requirement, for those interested in birds to shoot and collect them, and in that way 'enjoy' a really close-up view. Stephen Moss, in his fascinating social history of birdwatching: A Bird in the Bush, points out that even those who did own binoculars still faced problems and that ' a Sussex vicar switched his attention from birdwatching to botany because whenever he went out carrying a pair of binoculars his parishioners thought he was off to the races!'.

Alexander's parents-in-law lived at Cambridge in the 1930's and when he went to visit he was constantly at the sewage farm; their reaction is not documented. This was not the farm as we know it today, which became defunct, I believe, in the late 1960's, but an extension of the one which was first established in 1895. Initially the significance of sewage farms as bird habitats was little understood and not much is known about their early ornithology, but gradually their importance as feeding areas and breeding sites became better appreciated. The old-style farms were large, often occupying 200 acres of land or more. Whereas sewage from many of our towns used to be discharged directly into the rivers, during the second half of the nineteenth century sewage farms were widely established to improve water sanitation. The process of purifying sewage brought into being a very varied series of bird habitats from filter tanks to sludge drying beds, which not only encouraged insect life but also contained the seeds of numerous plants found attractive by birds. In the older sewage farms the treated sewage liquid used to be run over open fields which formed marshes where lots of different kinds of wading birds could be found. Cambridge farm was renowned for attracting rarities in its heyday; Alexander himself encountered an Upland Plover in 1932 and a Lesser Yellow-legs in 1934. He was equally excited to establish the regular visits to the farm of Water pipits, quite a feat of identification in his day. Eventually, the old-style sewage farms, although economic, were considered to be taking up too much valuable land, especially in suburban areas, and were gradually superseded by smaller chemical sites which released land for development. The A14 now runs through the area frequented by Alexander, although Milton Country Park, and its gravel pits, has reaped some of the benefit, although no longer attracting the myriad waders of previous decades.

My walks across the Histon fields have proved most rewarding in the last few days. On Monday 4th February I came across a large flock of upwards of 15 Siskin - I've only seen solitary birds in this country before - and the next day, which was also bright and sunny, four Skylarks were up and singing. This must be one of Britain's best-loved birds and a sure harbinger of spring and summer. Their song, which has the twin objectives of defending territory and attracting females, is heard regularly from late January until early July, and less often at other times of year. They tend to be fairly silent in August and September. In the past they didn't have quite so much to sing about as they were exploited as food. Leadenhall market, London, in early Victorian times, managed to get through 400,000 a year. However, these - to us - shocking figures, help testify to the bird's previous abundance and it's ironic that it is in our own age of increased environmental awareness and concern, that the bird, Shelley's 'blithe spirit', has suffered its greatest losses, especially in our region's grain-growing 'deserts'.

Despite the spring-like weather of mid-February hundreds of Fieldfares have still been feeding on the recreation ground and will probably stay until well into March.

Ken Sheard