ИСТИНА

In most hybrid zones between closely related taxa, clear evidences of song convergence as a consequence of hybridization and/or mutual vocal imitation occurs. In the sympatric zones (but not in the allopatric ones), males “understand” each other’s songs and treat them as a relevant stimulus for response. In species with a complex song and/or ability to learn songs over a long period of life (Nightingales), a significant role is played by the processes of mutual copying. Asymmetry of interspecific copying occurs in some closely related species. Some phenotypes in hybrid zones show an impressive stability in spite of the foreign DNA introgression.