Morphometric Variation as a Proxy for Dispersal in a Highly Dimorphic Reed Bird Specialist from an Isolated and Vulnerable Small Population in SE Spain

Authors: Peiro IG*

DOI: 10.23880/izab-16000352

Volume 5, Issue 1

Abstract

In this study, I gathered a comprehensive set of measures in a sample of 63 Bearded reedlings Panurus biarmicus, a small and highly dimorphic passerine bird vulnerable in Spain, ringed in the years 2003-2007 and 2009-2010 in an isolated population in “El Hondo Natural Park, SE Spain”. Most morphometric parameters were greater in adult males than adult females, irrespective of age groups and they were correlated with weight and size and this implicates that they are size and conditiondependent (most costly to produce) so enhances individual's quality or fitness to the bearer. GLMM’s models indicated that selective forces were stronger for wing-length than for tail-length, wing-length dependent by the age of juveniles and sex of males and determined by the weight. This suggests that both traits, especially wing-length, posses great individual fitness that could facilitate for quick movements for dispersal, probably started for juveniles. The earlier studied differences in the wing's shape in this species are probably the proxy factors to enhance dispersal started by juveniles, since they possess shorter drab tails. We need furthermore studies to evaluate if other populations of European plateau are intra and inter-sexual selected and if they are proxies or primers for dispersal and migration of this species.

Keywords: Intra and Inter Sexual Differences; Morphometry; Panurus biarrmicus; Small Population; Dispersal

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