Gesangsformen und Verwandtschaft der asiatischen Zilpzalpe Phylloscopus collybita abietinus und Ph. c. sindianus

Abstract

The territorial songs of two geographically isolated chiffchaff populations are analyzed. Songs of Ph. c. abietinus (Elburz Mts., Iran) are nearly identical with those of Scandinavian c. abietinus and Central European c. collybita. One third of the notes of Ph. c. sindianus (NW Himalayas) ascend in frequency at the beginning. Such notes are lacking in Ph. c. collybita and c. abietinus, but exist in the Siberian c. tristis. Playback experiments confirm the differences. Original songs of c. sindianus elicit a distinctly weaker reaction by German c. collybita than local songs. Artificial songs (made from natural notes) of ascending sindianus notes elicit ro reaction (J4, fig. 11). Earlier findings on parameters important for releasing territorial behaviour in the Central European c. collybita are largely confirmed and new results suggest minor differences only. 1) Notes in which the frequency of the second part is as high as the first part (P6, J11, J12; fig. 10, 12) may release strong or weak reactions. This depends on additional characteristics of the note, mainly of its 2. part. 2) Notes with very steep ascending angle (max. 91,5° : P7, also P6, J12, fig. 10, 12) release a strong reaction. Ph. c. canariensis with notes as steep as in c. abietinus and c. sindianus differ in the second part of the note. It inhibits the reaction of c. collybita of Central Europe. Regarding acoustical and morphological characteristics, Ph. c. sindianus is close to Ph. c. tristis. It cannot be treated a separate species. The nearest relative of c. abietinus is the Central European c. collybita. © 1981 Verlag der Deutschen Ornithologen-Gesellschaft.