Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 60. (Budapest 1968)

Horváth, L.: The evolutional significance of aberrations appearing in the plumage of the crossbill (Loxia curvirostra Linnaeus)

a clear state only on very few specimens, presumbaly on less than one per cent of the cases. Most of the aberrational specimens display no more than one, more or less developed, wing bar. In the followings, I submit 5 further female specimens, on which I also found similarly atavistic aberrational features, though there is no known literature data referring to any such "individual" aberration in the colour pattern. 29. L. curvirostra albiventris 9, Naryn, Turkestan, 13 July. A distinct, narrow, white bar on the tip of the primaries. 30. L. curvirostra 9> Zetelaka, Mt. Hargita, Transylvania, Rumania, 29 March, 1942. Two distinct, narrow, white bars on the tips of the primaries and secondaries, respectively. 31. L. curvirostra japonica 9> Japan, 1900. A distinct white stripe on the end of the primaries. 32. L. curvirostra albiventris juv. 9 > Issyk-kul, China. End of March. A distinct, narrow bar on the end of the primaries, and the traces of one on the end of the secondaries. 33. L. curvirostra himalayensis juv. sex? Sungpan-ting, Sechuan, China, 11 June, 1914. A distinct, narrow bar on the end of the primaries. Finally, I submit the data of the three pytiopsittacus specimens proved to be atavistic among the 28 examined birds. 1. Loxia pytiopsittacus çf, Sarkau, Kurische Nehrung. A very weak, whitish bar on the end of the primaries. 2. L. pytiopsittacus çf, Sweden, 4 April, 1891. A distinct, narrow, whitish bar and the traces of a similar one, on the end of the primaries and the secondaries, respectively. 3. L. pytiopsittacus juv. çf, Neustrelitz, 1964. A distinct, narrow, whitish bar on the tip of the primaries. To sum up, we can safely state that the atavistic features, demonstrable on the species of the genus Loxia, contradict on the one hand the distinct specificity of the two taxa, Loxia curvirostra and L. pytiopsittacus, and substantiate on the other the scientific hypothesis that L. curvirostra descended from L. leucoptera. Lioxia curvirostra is already well past the flourishing stage of specific differentiation, it had stabilized to a great extent, and therefore all subspecific segregations based on differences in hue and in measurements of the bill are founded on rather uncertain grounds. As shown by my investigations, this widely ranging species is strikingly homogeneous despite its extensive individual variability. It seems probable that its vagrant nature and its nesting in the most divers times and localities are the indirect causes to which the extensive variability, shown in overall hue and the size of the bill, should be asribed. In spite of all this apparent variability, the evolutional studies based on the atavistic aberrations evince the remarkable homogeneity of the species. The ecological conditions of the crossbills also testify to this end. With respect to food, the method of acquiring it, nesting conditions, and the feeding of the fledgelings, and as regards yet many other traits, the species of the genus Loxia are so uniform that hardly can any other similar instance be found in other genera. My sincere thanks are due to Dr. W. GÖTZ, Director of the Museum für Tierkunde, Dresden, and to G. MAUERSBERGER, Keeper of the Ornithological Collection of the Zoological Museum, Humboldt University, Berlin, for their cordial help in making available the rich and priceless research materials at their disposal. References: 1. CHERNÉL, I.: Magyarország madarai (Budapest, 1899, p. 618 — 621). — 2. HARTERT, E.: Die Vögel der paläarktischen Fauna (Berlin, 1910—21, p. 116—124, Zusätze und Berichtigungen, p. 2060 — 2062). — 3. MADARÁSZ, GY. : Magyarország madarai (Budapest, 1899—1903, p. 19 — 21, 165-166). — 4. WITHERBY, H. F., etc.: The Handbook of British Birds (1, London, 1952, p. 93-102).