Nature Studies

An incomer’s discovery of the natural world in the West Country

So here we are with the hardest of the winter weather coming right up, and the dilemma presents itself: do we feed the birds in the garden, or do we not?
Until just over fifteen years ago this question was a no-brainer. Why wouldn’t we feed our beloved garden birds and help them get through to the spring? But then, starting in 2005, one of the most colourful, the greenfinch, began to disappear. It certainly disappeared completely from our small garden in west London where the flash of the male’s yellow wing-patches had long been an enchanting sight.
Eventually the reason for its vanishing was discovered: the birds were being killed off by disease. To blame was a newly-emerged infection called trichomonosis, being spread by a parasite which had previously only been found in pigeons and doves. Now it had jumped the species barrier into greenfinches, where it caused throat lesions which prevented them from swallowing, so they were starving to death. But almost as worrying as the discovery of the disease itself was the discovery of the mechanism of transmission—for it turned out to be garden bird feeders. The parasite was being carried in the saliva of the birds, and at bird tables and feeding stations where many of them congregated—and contaminated the feeders with their saliva—it was being passed from one to another.
It was an extraordinarily powerful mechanism, because in Britain the putting out of sunflower hearts, peanuts, fat balls and all the rest of the avian menu is a gigantic activity: it is estimated that 17 million households take part, and we spend about £300m on it annually. Think about it: if you’re a greenfinch, seventeen million potential death traps are out there waiting for you, set by householders who only wanted to do you good. And the British population of these lovely creatures has duly collapsed: between 2008 and 2018, it dropped by 67 per cent.
Now the situation has become even more urgent because trichomonosis is starting to kill off the greenfinch’s close relative, the chaffinch, which some people might feel is an even lovelier bird. About 2013 the chaffinch population started to decline markedly and by 2018 it had dropped by nearly a third compared to the level of a decade earlier. It was suspected that trichomonosis might be to blame, but it was not until last September that a new piece of research by ornithological scientists showed that this is almost certainly the case.
I have to say that I feel an extraordinary pang at the idea that we might be killing off our chaffinches with kindness. I dearly love this bird, not only for the breeding male’s stunning plumage of blue and pink and black and white, but also for his song, that descending cadence with a flourish at the end, for me one of the most charming sounds of the spring. And I have an even worse fear; there is some suggestion that trichimonosis might spread to the bullfinch, the loveliest finch of all. In London we never caught a glimpse of Pyrrhula pyrrhula from one year to the next, but when we moved west we found we were in definite bullfinch country; I have seen several around the village, and on a wonderful morning a year ago one of them perched in a bush ten yards from our kitchen window, a great winged blossom of rose-pink, grey and black; it was an indescribable thrill. (The one finch that so far seems immune is the goldfinch, whose population has exploded thanks to the nyjer seed which they find irresistible).
So is it better to feed your garden birds or not? The answer is, on balance, yes, as long as you clean the feeders. You have to take them down and wash them, preferably with disinfectant, at least once a fortnight, and preferably once a week. It may seem like a pain, but it’s a necessary one, and a small price to pay for the delight garden birds give us.
I’ll be doing it, as the hard weather arrives. I’m one of the 17 million; I’m a part of the £300m bird food economy, a not insignificant one, in fact: when I bought my supplies for this winter, the girl in the garden centre smiled as she rang them up on the till, seeing them come to an eyebrow-raising £75. “Lucky birds,” she said.
Well, yes; as long as I make the effort to keep the feeders clean.

Recently relocated to Dorset, Michael McCarthy is the former Environment Editor of The Independent. His books include Say Goodbye To The Cuckoo and The Moth Snowstorm: Nature and Joy