CAROTENOIDS IN BIRD PLUMAGE - THE PATTERN IN 3 LOXIA SPECIES AND IN PINICOLA ENUCLEATOR

We studied the carotenoid pigments in the plumage of Loxia curvirostra , Loxia polygina, Loxia leucoptera and Pinicola enucleator. The pigmen ts were extracted under mild conditions and the extract analysed by hi gh-performance liquid chromatography coupled with mass and ultraviolet -vis spectroscopy. In adult females and young males of Loxia, two majo r carotenoids, all-trans epsilon, epsilon-carotene-3,3'-dione and 3-hy droxy-epsilon, epsilon-carotene-3'-one, were responsible for the yello w colour of feathers. Minor amounts of lutein and 3'-dehydrolutein wer e detected. With sexual maturation, males rum red. The red colour of f eathers was attributed to 3-hydroxyechinenone (3-hydroxy-beta, beta-ca roten-4-one); small amounts of other orange-red carotenoids such as as taxanthin (3,3'-dihydroxy-beta, beta-carotene-4,4'-dione), adonirubin (3-hydroxy-beta, beta-carotene-4,4'-dione) and canthaxanthin (beta,bet a-carotene-4,4'-dione) were also detected. Varying amounts of the yell ow carotenoids found in females and young males were present. The same red pigments are observed in the adult males of P. enucleator. In con trast, in adult female and in young male pinicola, lutein and 3'-dehyd rolutein were the major carotenoids. Two other carotenoids, not previo usly observed in bird plumage, were tentatively assigned to 3-hydroxy- beta, psi-caroten-4-one and 3-hydroxy-beta, psi-caroten-4-one (5'-cis) .