Thursday, May 14, 2009

Geriatric Great Tits

Great tits live long enough in the wild to suffer the burden of old age. As the years pile up, the birds become less able to raise healthy chicks and produce fewer young.
The findings,
recently published in the Proceedings of the Royal Society B, come as a surprise because it was thought that wild birds die well before the onset of ageing.
The most important finding is that female great tits living beyond 2 years of age show reduced offspring production. This means that at any time 1 in every 5 breeding females is affected by ageing.
Generally studies of this nature only collect data on first egg dates, clutch sizes, hatching dates and fledging rates – but make no attempt to relate that back to the age of the maternal parent. This report is unique to that extent.
And to paternal parents: 14 percent of chicks are not fathered by the male who raises them, so age-specific parentage is not accurate.

http://planetearth.nerc.ac.uk/news/story.aspx?id=420

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