1. ¹Laboratoire de Biologie des Populations d'Altitude (CNRS UMR 5553), Université Joseph Fourier, BP 53, F-38041 Grenoble cedex 9, France
2. ²AROMP, Muséum d'Histoire Naturelle, 35 allée Jules Guesde, F-31000 Toulouse, France

Correspondence: Sophie Questiau, Laboratoire d'Evolution des Systèmes Naturels et Modifiés (CNRS UMR 6553), Campus de Beaulieu, Av. du Général Leclerc, F-35042 Rennes cedex, France. E-mail: sophie.questiau@univ-rennes1.fr

³Present address: Laboratoire d'Evolution des Systèmes Naturels et Modifiés (CNRS UMR 6553), Campus de Beaulieu, Av. du Général Leclerc, F-35042 Rennes cedex, France

Received 8 May 1998; Accepted 31 March 1999.

Abstract

Common Crossbill subspecies have been described according to morphological traits, vocalizations and geographical distribution. In this study, we have tried to determine whether the subspecies correspond to clear-cut mitochondrial DNA lineages, by sequencing 717 bp of the control region from individuals taken at several sampling locations in North America and the Western Palaearctic. We find 22 haplotypes from the 37 sampled individuals with a mean divergence of 0.0118 0.0069 (mean SD). We find a mixing of the mitochondrial haplotypes at the continental level among the different types or subspecies previously described. Morphological differentiation (in bill size and shape essentially) shows the possibility of rapid local adaptation to fluctuating resources (coniferous seeds), without necessarily promoting the development of reproductive barriers between morphs.