RESEARCHERS WORKING in the irradiated zone around the disabled Fukushima nuclear plant say bird populations there have begun to dwindle, in what may be a chilling harbinger of the impact of radioactive fallout on local life.

In the first major study on the impact of the world’s worst nuclear crisis in 25 years, the researchers from Japan, the US and Denmark say that analysis of 14 species of birds common to Fukushima and Chernobyl shows the effect on numbers is worse in the Japanese disaster zone.

Published next week in the journal Environmental Pollution, the paper says its findings demonstrate “an immediate negative consequence of radiation for birds during the main breeding season March-July”.

Two of the study’s authors have spent years working in the irradiated 2,850sq m zone around the Chernobyl plant, which exploded in 1986. A quarter of a century later, the zone is almost devoid of people.

Timothy Mousseau and Anders Pape Moller say their research there uncovered major negative effects among the local bird population, including reductions in longevity, male fertility and birds with smaller brains.

Many species show “dramatically” elevated DNA mutation rates, developmental abnormalities and extinctions, they add, while insect life has been significantly reduced.

Some scientists have challenged the findings, arguing that animal and insect species have thrived around Chernobyl’s almost uninhabited shadow.

Prof Mousseau, a biological scientist, at the University of South Carolina in the US, says however that there is “no data to support that thesis”.

Prof Mousseau says the fresh findings are of “profound” interest because Fukushima presents the first opportunity to monitor the impact of a large-scale nuclear disaster “from day one”.

In a 2003 judgment by a Danish academic body, Prof Pape Moller was found to have been guilty of “a falsification of the scientific message”.