EGGS IN DANGER NEAR FEEDERS
FEEDING BIRDS IN GARDENS CAN INCREASE PREDATORY ATTACKS ON NEARBY NESTS, ACCORDING TO STUDY.
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Two independent studies – one in England, the other in North America – have found that feeding birds doesn’t have wholly positive outcomes for the birds themselves.
Researchers at the University of Reading used artifical nests filled with quails’ eggs to gauge the extent of predation.
“About 10 per cent of the nests survive if they are near a feeder and 50 per cent survive if they are not,” said Mark Fellowes, who led the work.
Camera-traps trained on the nests revealed magpies, grey squirrels and jays were the main culprits.
Jennifer Malpass and colleagues at Ohio State University monitored the fate of American robin and northern cardinal nests over a four-year period. The effect was inconsistent, but arose especially when feeders and predators were numerous.
Fewer than one per cent of American robin nests survived in neighbourhoods with the most feeders and crows compared to up to 34 per cent when these were most infrequent.
Using feeders fitted with guards designed to exclude predators had little effect.
“We think predators are attracted by the presence of food, even if they can’t get to it, and then they forage opportunistically around the feeder,” said Fellowes. Guards can help in other ways, though, he said. “There’s evidence that, with unguarded feeders, squirrels are taking more than half the food. So all that’s doing is fuelling the production of more predators.”
Other precautions available to householders include setting feeders away from trees and hedges. The danger zone around a feeder is hard to pin down, but Fellowes estimates it is between 10 and 50m.
The content of the feeders also matters. “Niger seed is better because magpies and squirrels won’t go for it like they go for peanuts,” said Fellowes.
In a statement the RSPB said that nest predation “does not significantly impact on the overall populations of our UK garden birds.” Written by STUART BLACKMAN