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British bird feeders transform garden pecking order (1 Viewer)

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I've reproduced the article as there is a pay wall in The Times online unless one is a subscriber.





Never in the evolutionary history of birds has such a large ecological niche opened so quickly.

Bountiful supplies of food were suddenly available through the harshest winters, endless caches of nuts appeared and were continuously refilled — and all were there to take for the bird that could adapt.

The niche appeared not because of the end of an ice age or the arrival of a new species, but thanks to something far more disruptive: the patio bird feeder.

A study has investigated the “profound” biodiversity effects of this British habit, largely begun in the 1970s, of leaving out nuts for the birds.

It has concluded that this new food source, which today supports an estimated 196 million birds a year, has drastically changed the composition of birdlife in our gardens, largely for the better.


Kate Plummer, of the British Trust for Ornithology and University of Exeter, said: “Because we are so accustomed to putting out feeders, and it is now such a part of our culture, we forget it’s a huge increase in the food that’s available to these birds. You can only imagine the extra feeding resources available.”

She and her colleagues were able to use data from across a 40-year period to show just what this meant. Tentatively at first, but then with increasing gusto, species have learnt to exploit this new source.

The first to come to our patio windows were the boldest and most populous, the sparrows and starlings, but over the years they have been joined by others — to produce a far more diverse display. The result is that for the birds that adapted, feeders may have altered the course of their species. Among the biggest changes has been in the goldfinch, which has gone from being spotted at 10 per cent of feeders in the 1970s to 80 per cent; the sparrowhawk, which in the 70s was almost absent from feeders but is now seen at 60 per cent; and the great spotted woodpecker, which has gone from 20 per cent to 70 per cent.

Writing in the Nature Communications journal, Dr Plummer and her colleagues said that no one could have anticipated that a trend started by people who wanted to watch birds over breakfast would have major ecological consequences.

“Individual decisions by homeowners to feed wild birds can impact cumulatively upon bird communities,” they said. “As such this growing, global phenomenon has profound potential to influence biodiversity further and should not be underestimated.”

Dr Plummer said that some of this change in species seen at feeders probably reflects a better understanding of what birds want to eat. Over the years, as the popularity of feeders has grown, nuts have been joined by a more diverse set of offerings including seeds and even fat balls. But there is also evidence that birds themselves are adapting.

Recent research from scientists at Oxford University found that the beak length of tits in Britain had changed markedly in a short time, something they attributed to the effect of feeders. Tits whose beaks could better grip nuts through the mesh were the ones who survived, thrived and proliferated.

“Putting out all this food is affecting what we see around us,” Dr Plummer said. The study showed that, in Britain, this had been broadly for the good. “I think it is important to know that what we do personally in our gardens can contribute to something positive. When there’s so much else that is changing their numbers in the other direction, it’s nice to see something doing the reverse.”
 

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