Girton Birdwatch - November 2006
I have been warned not to make this column too esoteric and to avoid mentioning my holidays. After this month I promise to pay heed to this advice! In September my family visited Northern Mallorca, the first time we had holidayed there so late in the year. My daughter, Eleanor, flew in from Leeds and I made the rash promise that I would introduce her to "her" special bird: Eleonora's falcon. This is a regular spring and summer visitor to the island and in the past we'd been lucky enough to come across the odd individual. This time, at the tip of the Formentor Peninsular, the sky was full of them (well, eight at a time!) My excuse for mentioning them in the context of an essentially local (regional?) review is that in September reports came in that the bird had been sighted in Norfolk. This caused great consternation on local and national "bird-lines" because Eleonora's falcon is usually only to be found breeding on a limited number of rocky islets in the Mediterranean, migrating eastwards from there to East Africa and Madagascar. Little information exists on its winter habits. What is clear is that any visit to Britain by this bird is a very rare occurrence and perhaps to be viewed with suspicion. Hence the suggestion from birders that what had been seen was more likely to have been a dark, juvenile Peregrine or a Red-footed falcon (a rare migrant to Britain, but with several being reported every spring). Accusations of 'stringing' were made, this being birder slang for an erroneous record due to incompetence, over-enthusiasm or worse! However, other correspondents pointed to reports of the bird previously showing up in Scilly; Fiddler's ferry, Cheshire; Formby, Lancashire; the Western Isles of Scotland and the definite presence recently of three birds in Sweden.
It is very difficult to confuse an Eleonora's with a Peregrine falcon: it is a much more slender bird, like a large swift, and significantly smaller than a Peregrine, with a longer tail and more tranquil, elegant flight. It could be mistaken for a Hobby but is larger and, again, has a more delicate structure, with finely shaped wings and longer tail. It is generally a darker bird but even in its light phase its under-parts appear darker than the Hobby because it is more heavily streaked.
It is gregarious, nesting in colonies and often hunting in groups for large insects and small birds (sometimes by moonlight). Breeding may be confined to the autumn with the timing coinciding with the abundance of migrating prey. Flocks of a hundred or more birds have been known to hunt together, forming a barrier to migrants 1000 metres high and several kilometres long.
On a more disturbing note Bob Benton drew my attention to a parasitic disease which has been infecting our garden birds, especially the finches. Apparently, hundreds of greenfinches and chaffinches are being wiped out - especially in the South West and Midlands - although other members of the finch family, including goldfinches, linnets and siskins, have been found to be susceptible to the parasite. The disease, known as trichomoniasis, is no threat to humans and has no connection to avian flu, but can cause birds a painful death lasting many days or even weeks. The parasite is transmitted through water, infecting the throat and crop, causing the bird to dribble saliva, and creating difficulty in breathing and swallowing. Birds regurgitate food and show general signs of illness such as fluffed-up plumage, lethargy and a marked reluctance to fly. The disease is believed to be spread by birds sharing feeders and baths which have become infected by their saliva. People are being advised to clean up their bird-tables and feeders, using a brush dipped in a weak solution of detergent, drying everything thoroughly afterwards because lack of moisture is the best way to kill the parasite. It is advisable to wear rubber gloves and to move feeders around the garden to avoid infection hot-spots. In the event of a suspicious death all watering and feeding should be stopped for a couple of weeks. Remember not to touch or handle any sick or dead birds. If you should be unfortunate enough to encounter unexplained bird deaths in your garden you are asked to contact the Garden Bird Health Initiative on www.ufaw.org.uk It is not just finches which are affected as the parasite is common in pigeons and collared doves and may be transmitted to birds of prey which feed on them. No one is quite sure about the scale of the outbreak or why it has occurred. One tentative theory is that the recent hot summers, and in particular this year's extremely hot July, may be implicated. The species most badly affected seem to be those sociable birds which enjoy living in large groups.
Although vigilance is called for it is too soon to say whether the disease has reached Cambridgeshire. Don't be misled by the possible absence of finches from your garden at the moment. This is a natural pattern and they are just as likely to be enjoying the bounty of seeds available in the surrounding fields and hedgerows, as succumbing to disease. I came across lots of greenfinches, chaffinches, yellowhammers, green woodpeckers and meadow pipits, during a mid-October walk from Girton to Westwick. There are large flocks of native and migrant starlings about, and fieldfares and redwings are arriving in increasing numbers, although they are avoiding the Recreation Ground at present. There has also been a relatively heavy influx of yellow-browed warblers to the region - a rare but regular autumn visitor to western Europe from its Asiatic range - so perhaps one may stray this way!
Ken Sheard, Ken.sheard2 at ntlworld.com