The relative importance of biotic and abiotic variables on the Common Kingfisher Alcedo atthis breeding distribution in northern Iberian rivers was quantified through surveys completed in 2007. Eight rivers were surveyed for "positive" and "negative" (control) breeding territories (PBT and NBT, respectively). PBT (N = 9) were 3-km river sections with breeding pairs; NBT (N = 8) were 3-km river sections close to PBT, where no pairs were found, with apparently similar features to the PBT and one

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... r more cut banks suitable for nesting. Stepwise discriminant analysis (SDA) correctly classified 94.1% of territories and revealed PBT was associated with higher oxygen concentrations, a lower maximum depth and lower proportion of rockfills. Causes and consequences of these findings are discussed.