Vögelstudie in England beginnt - Anzahl der Spatzen stark zurückgegangen
Quelle: Observer, 12. Januar 2003
Wissenschaftler schlagen Alarm: Anzahl der Spatzen in Großbritannien fast auf die Hälfte zurückgegangen - in London sogar um 75 %
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Nachdem die Anzahl der Spatzen in Großbritannien seit 1994 auf fast die Hälfte zurückgegangen ist (in London um 75 %), soll jetzt in einer Großstudie untersucht werden, ob die explosionsartige Zunahme elektromagnetischer Wellen durch Mobiltelefone die Spatzenpopulation auslöscht. Rosie Cleary, die vom British Trust for Ornithology beauftragt wurde, das Problem zu untersuchten, erklärte:
"Das Verschwinden der Arten aus großen Städten fällt zeitlich mit der Aufstellung von Mobilfunksendern zusammen.
Studien warnen vor den Wirkungen dieser Strahlung auf das Fortpflanzungssystem. Trifft dies auch auf die Spatzenpopulationen in den Städten zu?
Spanische Wissenschaftler fanden heraus, dass Vögel dazu neigen, Orte mit hohen Levels elektromagnetischer Verseuchung zu meiden. Mobilfunkmasten befinden sich an hohen Stellen für maximale Netzabdeckung, was eine Reduzierung von Arten erklären könnte, die bevorzugt auf Dächern nisten.
Originalartikel in Englisch:
Mobile phones blamed for sparrow deaths
30,000 birdwatchers to join study into the effect of electromagnetic waves on Britain's garden favourite
Mark Townsend
Sunday January 12, 2003
The Observer
The remarkable decline of the sparrow remains one of British wildlife's most enduring mysteries.
Cats, lead-free fuel and even loft insulation have all been blamed for the disappearance of 10 million house sparrows.
Now scientists seeking to unravel the cause of their disappearance have identified a new culprit: the mobile phone.
Britain's first 'sparrow tsar' is to investigate whether the explosion of electromagnetic waves from portable handsets is wiping out the species. Rosie Cleary, appointed by the British Trust for Ornithology to investigate the problem, said: 'The disappearance of the species from large cities correlates with the introduction of phone masts.
'Studies have warned about the effects of these radiations on reproduction. Are these interfering with urban sparrow populations?'
Cleary is leading a major study involving up to 30,000 birdwatchers, which will examine urban sparrow populations near mobile phone masts, where electromagnetic fields are most concentrated. London has witnessed the sharpest decline in the sparrow population - a 75 per cent fall since 1994, which coincides with the emergence of the mobile phone.
There are an estimated 40 million mobile users in Britain, with hundreds of masts scattered across England's capital.
The British sparrow population has almost halved in the last 30 years, from 24 million to less than 14 million.
Spanish scientists have found that birds tend to avoid places with high levels of electromagnetic contamination. Mobile phone masts are located in high places for maximum coverage, which could explain a decline in species which tend to nest in roofs.
Scientists said the latest attempt to solve the mystery was a logical step, but that evidence to support a definitive link was lacking.
Denis Henshaw, professor of physics at Bristol University, pointed to tests where the egg-laying ability of chickens had been affected by electromagnetic waves. Other studies have pointed to reduced sperm counts in rats.
'It is very difficult to determine the size of the effect. Humans face an increased cancer risk with long-term exposure, but the problem is that sparrows may not live long enough for that to be a factor.'
Henshaw added that electromagnetic waves could affect a sparrow's ability to navigate. 'Animals navigate by the Earth's magnetic fields and waves could disturb a bird's ability to find their way around. Though whether that leads to a decline in numbers is a matter of speculation.'
Alan Preece, Professor of Medical Physics at the University of Bristol, who has studied the effect of electromagnetic waves on humans, said he was sceptical of a link. 'The field of influence from a mast is quite localised - no more than 60 metres,' he said. Rewards offered for the first proper scientific explanations of sparrows' demise in urban areas remain unclaimed.
Among the many previous theories attempting to explain the decline of house sparrows, attacks by cats has been the most contentious. One study of a Bedfordshire village revealed that up to a quarter of its breeding pairs of sparrows may have been harmed by predatory felines.
The grey squirrel has also been blamed, although critics say they cannot often reach lofty sparrow nests to cause such a widespread decline.
Volatile organic compounds within lead-free petrol could, according to a widely discredited theory, affect bugs that sparrows feed to their chicks. Other studies have suggested a correlation between falling sparrow numbers and loft insulation.
The BTO's partly government-funded study will last 18 months, covering this year's and next year's breeding seasons.