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Message: <blockquote data-quote="bluechaffinch" data-source="post: 1750897" data-attributes="member: 19714"><p>With regard to ringing recoveries - these are at best a hit-and-miss affair and where small numbers of birds are ringed (I am assuming that the sample size for EO is small compared to most species) recoveries and the data produced by them should by no means be seen as representative: there is huge bias inherent in recoveries generally, especially where the recoveries are generated from random encounters with dead birds (I presume again that most recoveries relate to corpses rather than retraps). Of course we can make assumptions on the only data we have available, but the average distance travelled within a small sample does really permit us to be entirely confident about those assumptions: the sample mean is not the same as the actual mean. It is surely a rational position to state that these birds are physically capable of reaching our shores and, if our limited recovery sample doesn't fit, we at least admit that our data are insufficient to enable us to make a definitive statement that they do not do so. I read somewhere once "Believe the bird, not the book".</p></blockquote><p></p>