BREEDING birds can bounce back quickly when industry reduces heavy metal
pollution, Finnish researchers have discovered.
Tapio Eeva and Esa Lehikoinen of the University of Turku studied pied
flycatchers (Ficedula hypoleuca) and great tits (Parus major)
around a copper smelter at Harjavalta in southwest Finland. Heavy metal
pollution from the plant had reduced the breeding success of great tits.
Ten years ago, the plant began to reduce its emissions. By 1997, the nests
around the plant contained an average of one chick more than they had earlier in
the decade (Nature, vol 403, p 852). The researchers think the birds
are doing better because the insects which they feed on have recovered.
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However, Eeva warns that the cut in emissions may not help all species of
birds. 鈥淎lthough our results suggest a relatively rapid recovery of flycatchers
and tits in a polluted site, the pied flycatcher remains much lower there than
in the unpolluted sites,鈥� says Eeva.
He says that birds such as thrushes, which eat soil-dwelling invertebrates,
may take much longer to recover as the ground is still full of heavy metal
pollution from the years before the clean-up.