The Differentiation of Populations j 231 



Fig. 1 0.9 I Character displacement in Asiatic nuthatches. Bill length 

 and facial stripe in the two species are very different in areas where they 

 occur together but are quite similar where they occur alone. Populations 

 west of the zone of overlap ( Siita neumatjer) : A, Dalmatia and Greece; 

 B, Asia Minor. In the zone of overlap: C, Azerbaijan and Northern Iran; 

 D, Kermanshah; E, Luristan and Bakhtiari; F, Fars; G, Kirman. East of 

 the zone of overlap (S. tephronota) : H, Persian Baluchistan; /, southern 

 Afghanistan; /, Khorasan; K, north-central Afghanistan north of the 

 Hindu Kush; L, northeastern Afghanistan (Pamirs); M, Ferghana and 

 western Tian Shan. (After Vaurie, 1950, Am. Mus. Novitates 1472.) 



Bill length 

 32 mm 



31 



30 



29 



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21 



r 



Sitta tephronota 

 (broken lines) 



I 

 I 

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+ 

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C D E F G 



Sitta neumayer 

 (solid lines) 



I 

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HI J K L M 



