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Message: <blockquote data-quote="PaulD" data-source="post: 1712092" data-attributes="member: 11840">Thanks for the comments John.1.  Norwegian studies quoted in BWP indicate that young birds have a tendency to disperse towards the coast. Most Swedish EO ringing is of young birds and if they are indeed more likely (rather than less likely) to disperse towards the coast, but then show absolutely no inclination to undertake a relatively short sea crossing then I suggest it indicates that they don’t like sea crossings.2.  The median distance travelled from hatching place for Swedish birds recovered during summer (May to August), at least one summer after ringing is 52km (range 0-528 km, n = 66). 3.  Many of the recoveries of ringed EOs are of dead or injured birds (due to road accidents, power line collisions etc). So I wouldn’t expect any differing level of ringing effort in Denmark to be a major factor. Anyway, as in Sweden, there is an active birdwatching scene (Dansk Ornitologisk Forening etc).Swedish ringers quoted me figures of 6,663 EOs ringed in Sweden by 2003 and 1,805 recoveries giving a 27% recovery rate.Sure it’s always possible to come up with alternative hypotheses – it could be argued that Danish driving habits are better and their power cables are more bird friendly so recoveries in Denmark are less likely! But it seems to me a fair interpretation of Swedish ringing data to suggest that Swedish EOs don’t disperse very far and don’t like sea crossings. Again I’m not suggesting that EOs are incapable of sea crossings (Norwegian birds move relatively short distances between islands), but ringing recoveries and information from places like Heligoland indicate that sea crossings are a significant barrier to them.If you have information which shows EOs undertaking significant sea crossings then please detail it or provide a link to it as new information is always welcome.</blockquote>

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