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Message: <blockquote data-quote="Ficedula" data-source="post: 1706316" data-attributes="member: 81108">Thanks RobinD this helps a little. It is good to see it will be published in BB, but will any of the peers reviewing it be competent in assessing isotopic analysis?The comment by Kelly mentions only Deuteium/Protium ratios and that the bird appears to have "originated in an area with very low 2H/1H signatures".  Not confident what this means but i assume Deuterium very rare. Very low detection will mean high error potential so i hope the work includes analysis of other isotopes such as 16O/18O.what is the difference in 2H/1H ratios between Scandinavia and Northern Britain? Trawling the internet i only find very low resolution maps that suggest very little.Presumably the Hydrogen is getting into birds via water, drunk or in food (do owls drink much?) and not inhaled water vapour (confirm anyone?). If largely via food then the isotope ratio is only suggesting the origin of the food, not the bird, thus an assumption is being made that all captive owls are fed on locally sourced food (perhaps reasonable but still an assumption). Even if they are, this bird could have been reared in captivity in Scandinavia then escaped and made its own way to Britain or been imported (illegally?).Even if it is shown that this Eagle Owl got here under its own power from a wild population, so what? extrapolating such a result to the current GB population is too much.I am aware that much of the concern here is in opposition to the proposed extirpation of the GB population. I too oppose culling of GB Eagle Owls but feel that appealing to such tentative "evidence" will not help. It is too easily dismissed. Far better to highlight the absence of evidence of harm to GB species in the hands of those who support a cull.</blockquote>

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