Meeting Abstract

P2.34  Tuesday, Jan. 5  Secondary contact zone in central Sweden for Willow Warblers Phylloscopus trochilus identified using stable isotopes, AFLP molecular markers, and morphometrics LARSON, K.W.*; BENSCH, S.; MÜLLER, N.; ÅKESSON, S.; Lund Univ., Lund keith.larson@zooekol.lu.se

Willow warblers (Phylloscopus trochilus) are one of the most abundant Palaearctic-Africa migrants that breed throughout Eurasia and winter in sub-Saharan Africa. On their breeding grounds in Sweden there exist two subspecies. Bensch et al. (1999) documented that these two subspecies use different migration routes using ringing recovery data forming a migratory divide at the secondary contact zone. P. t. acredula breeds in northern Scandinavia and follows a southeasterly route during autumn migration and to spend the winter in southern Africa. In contrast, P. t. trochilus breeds in south Scandinavia and migrates towards southwest in autumn to winter in western Africa. Adult birds from the two subspecies meet and potentially mix in a narrow secondary contact zone in central Sweden between 61° and 63° north latitude. We used stable carbon- and nitrogen-isotopes, two AFLP (amplified fragment length polymorphism) markers, and morphometrics to more precisely identify the secondary contact zone. With the contact zone identified, we plan to investigate the consequences of mate choice on population dynamics, assortative mating, breeding performance and consequences of inter-breeding on the genetic migration programs of individual birds.