Morphometric and allozymic differences between Bearded Tit Panurus biarmicus (Aves: Passeriformes) subpopulations in a large wetland and a small pond in central Anatolia, Turkey

The Bearded Tit (Panurus biarmicus) is a small passerine bird occurring only in wetland habitats. Three subspecies of the Bearded Tit are known from Turkey. The endemic subspecies Panurus biarmicus kosswigi has only been recorded from Amik Lake in Turkey. This subspecies is now considered extinct; the apparent cause of this extinction was the drought affecting the lake. Other subpopulations might be similarly threatened by habitat loss. Therefore, it is important to investigate the morphometric characteristics and genetic variation of these local subpopulations. In this study, body weights and 12 morphometric characters were measured for Bearded Tit individuals in the Eber Lake and Behiçbey reedbed subpopulations. Statistically significant differences were found in extended wing length, maximum wing chord, and weight between the 2 subpopulations. Allozymic variation was also studied in the 2 subpopulations. Genetic variation was assessed using isozyme systems, and 8 of 21 loci (Pgm, Me-I, Me-II, Fum, Est, Mpi, Pgd, and Acon-M) were found to be polymorphic. The percentage of polymorphic loci was higher at Eber Lake (P95% = 38.1%) than in the Behiçbey reedbed (P95% = 33.3%). The mean FST (0.048) and Nm (5.0) values showed high levels of gene flow between these subpopulations.