MORPHOLOGICAL PATTERNS OF A NIGHTINGALE POPULATION IN A CONTACT ZONE OF LUSCINIA MEGARHYNCHOS AND L. LUSCINIA

摘要

We investigated morphological characteristics of a population in a contact zone of two sister species of nightingales in North-East Hungary. The aim of our study was to analyse and interpret the current morphological patterns of a nightingale population in three populations, called Bódva, Tiszalúc-Bárányszeg and Tiszabercel-Tiszatelek. The research was carried out between 2006 and 2010 at the northern sites of rivers Tisza, and Bódva, where 63 nightingales were examined altogether. The three populations were compared with each other for several morphological characteristics. The populations were significantly different in wing-pointedness, wing-symmetry and body mass and, although marginally, in tail length. Based on the combination of two morphological traits (the relative length of the short first primary and the proportion of length of the second and fourth primary), seven (11.1%) of all investigated birds were identified as interspecific hybrids. In conclusion, we suggest a possible interspecific hybridization between the two nightingale species in the studied area. We assume that the modification in the structure of riverine vegetation might be one of the reasons of the relatively high proportion of hybrid individuals.