Feeding garden birds in Spring leaves their eggs exposed to predators (2024)

Feeding birds during the breeding season makes it five times more likely their nests will be raided by grey squirrels, magpies and jays, an experiment by the University of Reading discovered.

This is because predators are also attracted to the food, and then explore further afield to find nests.

While the RSPB advises people to feed birds all year round to help them survive food shortages, scientists at the University of Reading, who conducted the research, say caution is needed in the spring.

They advise putting out small nyger seeds, rather than the squirrels’ favourite of peanuts, and keeping feeders well away from nesting sites.

Professor Mark Fellowes, head of biological sciences at the University of Reading, said: ‘Feeding wild birds is a fantastic way to connect with nature and has many benefits for both birds and people, but our research shows that if we’re not careful we may accidentally cause harm.’

The researchers carried out more than 100 tests, placing artificial nests containing quail eggs five and 10 metres away from hanging peanut feeders.

Camera footage showed almost nine out of ten nests near filled feeders were raided, compared with just under 50 per cent of those close to empty ones.

The study found just as many nests were raided near feeders with predator guards, despite the guards greatly reducing visits by grey squirrels and magpies.

Jays are believed to be responsible for visiting these feeders, despite being unable to access them, and tracking down eggs.

Doctoral researcher and lead author Hugh Hanmer said: ‘The importance of jays was unexpected, as they didn’t visit feeders but as clever corvids it’s likely that they’re foraging near where they see other species feeding.’

Nearly half of households in Britain put out food for wild birds like robins, blue tit* and goldfinches, with a study in Reading finding two-thirds do so all year round.

The bird feeding industry is estimated to be worth £200 million ($250 million), with enough food supplied every year to sustain more than 30 million garden birds.

However it can affect where birds as diverse as hummingbirds and blackcaps choose to nest.

The study was artificial in that the nests used by the researchers were not defended by birds, but found feeders may attract predators to an area even when they cannot reach the food themselves.

The researchers say putting a feeder around 40 yards (40 metres) away from a nest could cut the added risk from predators.

Professor Fellowes said: ‘We’d just recommend that people should take care during the breeding season if nest predators are being attracted to their gardens.

‘The easiest solution is to place feeders well away from potential nest sites, or to provide food which is less attractive to squirrels and magpies.’

An RSPB spokesman said: ‘This new paper is an interesting contribution to how we can best help our garden birds, and as we do with all such findings, we will carefully consider the evidence.

‘People who feed birds in their gardens want to help their local wildlife, so we will continue to ensure our advice helps provide them with the best available information necessary to do so.’