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N = number of recoveries. AM, arithmetic mean distance; GM, geometric mean distance; SD, standard deviation of distances. All figures refer only to species for which at least 50 recoveries were available for each age group analysed. From Paradis et al. (1998).

In these analyses, ringing and recovery occurred in the same area (Britain) for all species, so findings should have been comparable between them. This large-scale study covered a large number of ringing and recovery sites, thereby reducing to a minimum any systematic regional bias in reporting probability. All the birds were ringed in one breeding season and found dead at breeding age in a later one, excluding live recaptures by ringers which would have biased the records towards short moves. Records for the two sexes were pooled, even though they may have differed in dispersal distances. An assumption was that birds found dead in the breeding season were near their breeding sites.

aGeometric means calculated as the arithmetic mean of the loge distances, back transformed. bColonial.

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