. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. 122 Roald L. PoTAPOV Rule" was not accepted by all authors (Rensch 1934; TuGARiNOV 1946) and a correlation between wing sharpness and geographic latitude in conspecific pop- ulations was often applied instead: in northern popula- tions the wing is sharper than in southern ones. A detailed analysis of all facts was perfomied to test both hypothesis. The results did not support the correlation with latitude, whereas there were no contradictions to Sibome's Rule (
. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. 122 Roald L. PoTAPOV Rule" was not accepted by all authors (Rensch 1934; TuGARiNOV 1946) and a correlation between wing sharpness and geographic latitude in conspecific pop- ulations was often applied instead: in northern popula- tions the wing is sharper than in southern ones. A detailed analysis of all facts was perfomied to test both hypothesis. The results did not support the correlation with latitude, whereas there were no contradictions to Sibome's Rule (Potapov 1967). The rare case of Passer domesticus where northern populations are sedentary and the southern subspecies migrates (Potapov 1967) is mentioned in this connection: the migratory subspecies has shaiper wings, although it lives much farther to the south than the northern one (Fig. 2). %. J 1 I I 1 1 9 8 7 6 5 4 : The shape of the tip of the wings in two populations of the House Sparrow (from Potapov 1967): 1 - sedentary population in Central Europe; 2 - migrant population (Passer domesticus bactrianiis) in Southern Tadjikistan. All necessary variables for the estimation of wing sharpness can easily be taken from typical collection specimens where the wings are fixed in the naturally closed state. In this position, the wing is easier to measure than when it is dried in the open state. The reason is that drying of the open wing causes uneven desiccation of tissues, and feathers lose their natural posifion, whereas in normally folded wings this is not the case. For instance, in dried open wings of galli- form birds the first (shortened) secondary forms the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Zoologisches Forschungsinstitut und Museum Alexander Koenig. Bonn : Das Forschungsinstitut
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