In response to growing concerns about disease transmission among garden birds from supplementary feeding, the RSPB has stopped selling any products with flat surfaces such as table and window feeders.
The move comes while it is in the middle of a review of all bird feeders it sells and the advice it gives to its customers and members.
A statement on its website says that it has suspended the sale of “bird tables and related products, Table mix and Table mix extra, window feeders and feeder guardians with trays.”
It adds: “This is because there is evidence to suggest that some birds, particularly finches, can be more exposed to disease when fed on flat surfaces like these.”
Since 2006, greenfinches – the worst affected species – have declined by 66 per cent, while chaffinch numbers have dropped by about 40 per cent in the past decade. Goldfinches, conversely, have benefitted from the feeding bonanza, with their population increasing by 80 per cent in the decade 2002-2012.
The disease in question is trichomonosis which is caused by a microscopic protozoan parasite that lives in the upper digestive tract, respiratory system and other organs of birds. It was previously mainly known to affect pigeons and doves, but since 2005 has been observed in songbirds.
Affected birds can often be seen to be drooling saliva. They also have difficulty in swallowing and will regurgitate food, show signs of lethargy and exhibit laboured breathing.
But the RSPB’s decision to withdraw some of its feeders will not satisfy all wildlife experts. Dr Alex Lees, a reader in ecology at Manchester Metropolitan University, says there is ample evidence, disease transmission aside, that birdfeeding may be having a broader negative impact.
He cites as an example the increase in numbers of great tits, whose population has soared by 40 per cent, at least in part because of feeding. But this boom may have spelled bust for willow tits, which great and blue tits oust from tree cavities where all three nest.
“It is good to see that the RSPB is prepared to change its stance on how bird feeding should take place according to an emerging body of evidence, but we also need to make sure that the advice on the what, where and when of feeding are also evidence-driven to mitigate impacts on the environment,” Lees says.
And Dick Woods, who has designed and now manufactures feeders through his company Finches Friend, says it’s not just the flat surface feeders that are the problem. Those with ports that are open to the rain and where the perches are arranged vertically are also likely to lead to the transmission of pathogens, Woods says.
Garden finches under threat
Greenfinch
With their largely olive-green colouration and yellow flashes on their wings, male greenfinches are instantly recognisable. They have a quirky, wheezy call that’s heard in spring and summer.
Chaffinch
The male has rusty-red underparts and a blue grey cap, while the female is rather dowdier, but both have distinctive white bars on their wings. They prefer to feed on the ground.
Goldfinch
With its red face and bright yellow wing patches, the goldfinch cannot be confused with any other species. Often seen in small flocks feeding on seeds from plants such as teasel.
Main image: Greenfinches on flat bird table/Getty
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