Nazarenko A.A., Valchuk O.P., Martens J.
Zoologicheskiy zhurnal 1999; 78(3): 372-381
A revision of situation in the zone of overlapping (OZ) of Parus major and P. minor; populations in the middle Amur River basin was performed based on the field studies (1991-1996) and available literature. Dimensions and shape of OZ were determined for the first time; Its total range is about 250 km. Human settlements are typical habitats of P. major, secondary broad-leaved forests in the vicinity of these localities are populated by P. minor. The most sustainable state of interaction between the populations major and minor is their co-existence in human settlements, where local and limited hybridization takes place in a narrow belt of populations' contact. This is true for the central part of OZ. In eastern OZ, where both populations inhabit settlements, mixed populations exist; there is a tendency of displacing minor forms out of human settlements (Birobidzan city). The populations are shown to come in contact 100 years ago as a result of their dispersal due to transformation of the environment because of human activities.
