Volume 43, Issue 3 pp. 239-248
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Patterns of morphological variation among cardueline finches (Fringillidae: Carduelinae)

MATS BJÖRKLUND

MATS BJÖRKLUND

Department of Zoology, Uppsala University, Box 561, S-751 22 Uppsala, Sweden

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First published: July 1991
Citations: 10

Abstract

Patterns of variation in five morphological traits in cardueline finches were analysed. Among species, bill characters were the most and tail length the least variable. Species differed primarily in terms of body size, whereas genera differed in terms of bill size. Cardueline finches were far less variable compared with the amount of variation expected under a model of neutral random drift. This indicates that this group of birds is under strong stabilizing selection pressure. This could conform to models of stasis where populations are thought to travel only between adjacent adaptive peaks separated by shallow valleys. Changes in body size are correlated with speciation, whereas changes in bill morphology are correlated with divergences leading to the erection of new genera.

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