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)

all 36 specimens. The starting point to this is evidently a precise description of the pattern appearing on the upper wing coverts of the species L. leucoptera. The two-barred crossbill has, as implied in its name, two conspicuous, white cross-bands on the wing. The tip of the greater upper wing-coverts has a wide white zone with a very fine, pale rosy shade; this is the distal stripe. The proximal one consists of the confluent white spots on the end of the median and lesser wingcoverts. The two stripes are confluent because the visible section of the median wingcoverts is wholly white, while the lesser ones covering them are white only at the tips, and this latter also tends to a pinkish hue. Prior to the thorough discussion of the 36 atavistic aberrational specimens, I again wish to emphasize that I am unable to see justified the distinctness of Loxia curvirostra and L. pytiopsittacus, and thus join the camp of those who consider the latter as but a subspecies of the former. My standpoint is further strengthened by WITHERBY'S renowned book, the Handbook of British Birds, in which he contends that the subspecies Loxia curvirostra scotica HARTERT is transitional between curvirostra and pytiopsittacus, and if proofs will be forthcoming that the nominate form (Loxia curvirostra curvirostra

) also nests in Scotland, then Loxia curvirostra scotica will have to be regarded as the parrot crossbill ( Loxia pytiopsittacus ) : My studies disperses the uncertainties deriving from morphological systematics by reason of an evolutional foundation, since I found 3 atavistic aberrational specimens among the 28 examined pytiopsittacus individuals, which means 9.3 per cent. And there were, among the 248 curvirostra exemplars, only 33 aberrational ones, that is, 7.5 per cent. The sum total, as I pointed out above, is 36 aberrational individuals among the 276 birds, that is, 7.7 per cent. This implies that the revertal to the species Loxia leucoptera shows equal rates for both L. curvirostra and L. pytiopsittacus. The 33 atavistic specimens of Loxia curvirostra are as follows : 1. L. curvirostra çf, Samhof, Livland. A very narrow, white bar on the tip of the primaries. 2. L. curvirostra juv. rf, Heidelberg. Traces of a bar on the tip of the primaries. 3. L. curvirostra çf, Patára Cemi, East Borschomi, Anti-Caucasus, 6 March, 1963. Traces of a bar on the tip of the primaries. 4. L. curvirostra juv. rf, Kloster, Hiddensee. 3 Nov., 1956. Traces of a bar on the end of the primaries. 5. L. curvirostra rf Samhof, Livland. 18 Jan., 1898. A narrow, distinct bar on the tip of the primaries. 6. L. curbirostra juv. rf, Germany. A narrow bar on the end of the primaries. 7. L. curvirostra çf, Hellenorm, Livland, 18 Jan., 1890, A narrow bar on the end of the primaries. 8. L. curvirostra çf, Samhof, Livland. Traces of a bar on the end of the primaries. 9. L. curvirostra juv. çf, Samhof. Livland. Traces of a bar on the end of the primaries. 10. L. curvirostra luzonensis çf, Benguet, Irisan. 25 June, 1903. A narrow, distinct bar on the end of the primaries. 11. L. curvirostra himalayensis, çf, Lachen, 2700 m.a.s.l, Sikkim, 4 Nov., 1938. A narrow, white bar on the end of the primaries. 12. L. curvirostra himalayensis, 9> Koman-dse, South Tetung Range, 2 May, 1929. Two distinct but narrow bars ; one on the end of the primaries, the other on the tips of the secondaries. 13. L. curvirostra himalayensis, juv. çf, North Kansu, China, 5 May, 1930. Two narrow, white bars, on the end of the primaries and secondaries, respectively. 14. L. curvirostra himalayensis juv. çf, Lan-kau, North Kansu, 2 Febr., 1930. Two weak bars, on the end of the primaries and the secondaries, respectively. 15. L. curvirostra albiventris juv. çf, Darasun, China, 5 Nov., 1866. A narrow, white bar on the end of the primaries. 16. L. curvirostra tianschanica çf, Karakorum, Himalaya, Kashmir, 26 March, 1904. A narrow white bar on the end of the primaries. a