* Astronomy

Did modern birds originate around the time of the dinosaurs' demise, or have they been around far longer?
The question is at the centre of a sometimes contentious "rocks versus clocks" debate between palaeontologists, whose estimates are based on the fossil record, and scientists who use "molecular clock" methods to study evolutionary history.
A new analysis by researchers at the University of Michigan, the University of Chicago, the Centre for Biodiversity Conservation Mexico and Central America, and Boston University offers the strongest molecular evidence yet for an ancient origin of modern birds, suggesting that they arose more than 100 million years ago, not 60 million years ago, as fossils suggest.
The research was published online Jan. 28 in the journal BMC Biology.

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Extinct sea bird once again caught in the Hauraki Gulf
The once presumed extinct New Zealand storm petrel has again been recently captured in the Hauraki Gulf but its breeding site remains a mystery.
A team including Department of Conservation staff and scientists, funded jointly by DOC and a grant from National Geographics Committee for Research and Exploration, caught three birds during October and early November this year. This brings the tally to seven birds captured since the petrel was rediscovered by Dr Stephenson and Sav Saville of the coast of Whitianga in January 2003.

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The origin and early evolution of birds has been a major topic in evolutionary biology. In the 20th century, evolutionary scenarios posited either a  ground-based bird ancestor or an arboreal ancestor.
By comparing the claw curvatures of ancient and modern birds, researchers provide new evidence that the evolutionary ancestors of birds primarily made their livings on the ground rather than in trees.

The claws of Mesozoic birds and their immediate ancestors, the non-avian theropods, are relatively straightmost like of birds that are now either specialised for walking on the ground or have a preference for it, rather than the highly curved claws of birds that spend a lot of time in trees. We were particularly surprised by the fact that all the fossil species, representing evolutionary lineages from non-flying ancestors to early flying birds, had claws more like modern birds that spend most of their time on the ground - Christopher Glen of the University of Queensland.

The new study suggests that part of the problem is the loose categorisation of many living bird species as either ground- or tree-dwellers on the basis of their hind limbs when, in reality, these are not mutually exclusive alternatives. Rather, birds exhibit differing degrees of ground- and tree-based behaviours and would be better placed along a continuum according to the proportion of time spent on ground versus tree foraging.
To test the idea, Glens group first analysed the toe claws of 249 species of recent birds, revealing that their claw curvatures increase, becoming more hooked, as tree foraging becomes more predominant. They then compared the claw curvatures of modern birds to those of the fossilised ancestors of birds.

In summary, since claw angle is independent of body size and the evolutionary relationships among species, it is a reliable indicator of the predominant behaviour reliant upon hind-limb locomotion, and can make an important contribution to reconstructing the ecomorphology of fossil specieshow they lived and used their environments. Our findings suggest early birds foraged predominantly on the ground, rather than supporting previous suggestions of arboreal claw adaptations, which appear to have evolved later in the lineage.

Source Cell Press (subscription)

-- Edited by Blobrana at 00:35, 2007-11-06

The Chinese crested tern, a rare sea bird whose eggs are prized by some as a delicacy, is likely to be extinct in five years if authorities do not step up protection efforts, a conservation group said Friday.
The bird looks set to be the latest ecological victim of China's rapid 30-year economic expansion and industrialisation, which has raised the standard of living for hundreds of millions of Chinese but ravaged the environment. Late last year, scientists declared that a rare Chinese river dolphin was effectively extinct after conducting a fruitless six-week search for the creature in its Yangtze River habitat.

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