Food A'plenty - But Starving To Death
Bird On! News
15th April 1996
A horrific disease is affecting one of the commonest of Britain's birds - the Woodpigeon. A a tiny parasitic worm infects the birds' throats and eventually causes them to starve through being unable to swallow any food.
The tiny worm is called Trichomonas gallinae and it occurs widely in several species of pigeon. Usually it does no harm but over the last few weeks there have been widespread reports of Collared Doves and Woodpigeons dying.
Infected birds pass on the infection when food they are unable to swallow is spat out and, having become infected with the tiny protozoan parasite, is eaten by other birds in the flock. Dying birds are very thin and a cheesy obstruction can sometimes be seen at the back of the throat.
There have been very widespread reports from all over the country since the late autumn of a dearth of Woodpigeons in the fields. This has not been caused by the disease but because they have been feeding on Beech nuts - very plentiful this winter - and acorns in the woods.
In the last few weeks, they have started to bother farmers by eating crops like rape and clover. These birds, eating green vegetation, will not pass on the infection to the other birds feeding with them.
Cases of the disease have been reported from East Anglia and the Home Counties. It has possibly been particularly easily transmitted at feeding patches cleared of snow where the birds have flocked together very densely.
Chris Mead, of the British Trust for Ornithology, reported finding a Woodpigeon in his garden dying of this disease. Although there was plenty food available, the bird was "razor thin and weighed half the usual winter weight - and the local gamekeeper says there have been hundreds of other dead birds locally."
Woodpigeons are very common. At the end of the breeding season, there were certainly more than 10,000,000 in the country. It is unlikely that the disease will have a massive impact on the population.
Birds other than pigeons are seldom affected but the disease, known as frounce, is sometimes passed on to birds of prey fed infected pigeons. Most of the bodies of dead birds have not been eaten by scavengers.
Near the port of Great Yarmouth, local birdlovers thought that the pigeons and Collared Doves were being poisoned by the local council. This was not the case; it was simply an outbreak of this disease.
In a normal year there are isolated outbreaks of trichonomiasis all over the country, usually affecting Collared Doves coming to bird food. This widespread outbreak in Woodpigeons is thought to be unprecedented.