Feeding garden birds: in sickness and in health?

I first heard of Trichomonosis (or Trichomoniasis, as it is sometimes called) as a disease of garden birds about three or four years ago. The media were working with the British Trust for Ornithology and the RSPB to raise awareness of the illness and to encourage reporting of cases of sick birds so that the development of the disease could be better monitored.

Last year, I had first hand experience* of the disease affecting a greenfinch and a chaffinch in my garden: most probably because I was putting food out regularly for the one legged robin. But maybe not… that’s the thing with real life: there’s no “control” like there is in an experiment, so you can never know what might have happened had circumstances been different.

Anyway, in the early summer I saw a sick greenfinch in the garden. I was sufficiently aware of Trichomonosis to wonder whether that was what ailed this bird: its feathers were all puffed up; it was dopey and didn’t fly very far at all; it kept wiping its beak; and it generally looked a bit off-colour and sick.

A sick greenfinch, probably infected with Trichomonas gallinae
A sick greenfinch, probably infected with Trichomonas gallinae

I knew that the advice if you have an infected bird is to immediately stop feeding birds in your garden. And my first thought was to obediently obey this advice, but then I thought a bit more logically about it.

I live in a village and most of the households here feed the birds to some extent. So, if I stopped feeding the birds in my garden, they’d just move to somebody else’s garden…that could mean more mixing of birds, more close contact between them as they scrabbled for less food in a smaller area, and, consequently, the possibility of hastening the spread of the disease. Mmm, that didn’t sound like a clever plan after all. So I decided to continue putting out bird food.

There isn’t a whole lot of data on the prognosis for wild birds infected with Trichomonosis. The illness is caused by a parasite called Trichomonas gallinae. Infestation with this microbe can result in cankers growing in the oesophagus and crop (neck pouch) of birds. These cankers can get so big that they make eating and drinking difficult and the birds can starve to death, or become so weakened they’re susceptible to other ailments or just so lethargic that they’re easy prey, especially for domestic cats. However, often infection with the Trichomonas parasite either has no visible symptoms, or just very mild symptoms that the bird recovers from (and possibly develops immunity to the illness as a result).

There is, however, a lot of information available on the internet about the disease in general, its symptoms and how it spreads. An important point is that it needs to be transferred via a moist medium – it’s not robust and soon dies if it dries out. Consequently, drinking water put out for the birds could be a key place for the spread of the parasite.

So, I also thought about stopping putting water out for the birds. But there are gutters, puddles, troughs and ponds everywhere, as well as all the other gardens that have water bowls and baths for the birds. I was already in the habit of ensuring that the water for the birds was fresh each day and also that the water bowls were frequently cleaned with a bleach solution. So, I decided to continue with providing water too…

There isn’t really a tidy end to this story. I don’t know what happened to the two sick birds that were in my garden. Maybe they died, maybe they got better, maybe a cat ate them: who knows. But I am confident that suddenly stopping providing food and water to birds is going to cause them to go elsewhere, it’s not going to be a cure for the problem. Not unless a whole village or town stops at the same time, which is unlikely. So, if you do feed garden birds just do it as hygienically as you can: there’s nothing more you can do really.

RSPB advice on garden bird diseases including Trichomonosis

BTO information on Trichomonosis

This chapter from a field guide published by the US National Wildlife Health Center has detailed and useful information.

* it’s an assumption based on symptoms that the illness of these birds was Trichomonosis: to know conclusively would require laboratory testing.


2 thoughts on “Feeding garden birds: in sickness and in health?”

  1. It indeed seems so… I have 2 extensive bird-restaurants in my garden and it attracts all kinds of feather of (almost) all sizes… I haven’t encountered any sick birds these last years but then, I am not observing them all the time for obvious reasons 🙂

    But it is good to know more about things that can happen to them – so thanks for the info!

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