* Pesticides curb insect prey for swallows, starlings
* First evidence of knock-on effects beyond bees
By Alister Doyle, Environment Correspondent
OSLO, July 9 Insect-eating birds are in decline
in parts of the Netherlands where farmers have used pesticides
that are suspected of killing bees vital to crop pollination, a
study showed on Wednesday.
The report is the first evidence that neonicotinoid
pesticides, restricted in the European Union because of worries
about bees, are having knock-on effects on larger creatures by
reducing insect prey such as mosquitoes or beetles.
Barn swallows, starlings, mistle thrushes and tree sparrows
were among birds whose numbers had declined most in areas of the
Netherlands where a type of the insecticide had been heavily
used, according to the study, which was published in the journal
"To our surprise we did find a very strong effect" on birds,
the lead author, Caspar Hallmann of Radboud University in the
Netherlands, told Reuters. Nine of 15 bird species studied only
eat insects and all feed insects to their young.
"We cannot say this is proof (that the pesticide causes the
decline in bird numbers) but we cannot explain the ... decline
of birds by any other factors," Hallmann said. The study looked
into other possible causes, such as pollution, he said.
The European Union decided in April to impose a moratorium
on three neonicotinoids for two years on flowering crops because
of fears they are harming bees, which are vital to pollinating
The pesticides can still be legally used in the European
Union on non-flowering crops such as barley and wheat, the
scientists said, and are widely used in many other nations.
Producers of the pesticides, mainly Germany's
Bayer and Switzerland's Syngenta, have
contested the moratorium.
They suspect that other factors, such as a virus spread by a
parasitic mite, are behind the "colony collapse disorder" which
has seen bee numbers drop in Europe, Asia, the Americas and the
The Dutch study said that future legislation should take
account of the wider impact of pesticides on wildlife.
Pesticides that keep insects at bay protect crops worth billions
of dollars as food for people, even if they limit bird numbers.
Hallmann said he did not know if bans were needed. "We're
ornithologists, we're not toxicologists and not politicians. We
want to work together to find a solution," he said.
Dave Goulson of Sussex University wrote in a commentary in
Nature that the study was "the first to provide direct evidence
that the widespread depletion of insect populations by
neonicotinoids has knock-on effects" on larger animals.
Other animals, such as shrews and bats, also rely on
Professor Charles Godfray, an expert in pollination at
Oxford University, noted the authors had not proved that the
pesticides caused the decline. Still, he said the correlation
showed a need for "large, replicated field experiments in real
agricultural landscapes to get much harder data".
(Reporting By Alister Doyle)