. Bulletin of the British Ornithologists' Club. begin to grow, those of the male are rufous and of the female pale whitish. Finally, the proximal parts of the male's light-edged slate grey rectrices always have a few, irregular-shaped pale rufous spots concealed by the tail-coverts. On the other hand the female's rectrices are pale sandy coloured, with the two median feathers darker, and although the upper tail-coverts can have a few pale rufous tips, in my experience this is an irregular 3KS£^B Fig. 2. Juvenile $ and ^ Monticola imerinus. In both sexes the rectrices of the young are
. Bulletin of the British Ornithologists' Club. begin to grow, those of the male are rufous and of the female pale whitish. Finally, the proximal parts of the male's light-edged slate grey rectrices always have a few, irregular-shaped pale rufous spots concealed by the tail-coverts. On the other hand the female's rectrices are pale sandy coloured, with the two median feathers darker, and although the upper tail-coverts can have a few pale rufous tips, in my experience this is an irregular 3KS£^B Fig. 2. Juvenile $ and ^ Monticola imerinus. In both sexes the rectrices of the young are pointed and somewhat narrower than the adult's, a quite unusual feature in Monticola but found, for example, in Luscinia svecica cyanecula (Mayaud, 1938). This similarity and others mentioned later could have been attributed to convergence but for the analysis undertaken by Panov and Bulatova (1972), who found "a great similarity of karyotypes ... in the genera Oenanthe, Saxicola, Monticola and an approximation to them in Cyanosylvia svecica". Development of the juvenile dress was completed about the 40th day in the hand-reared birds and on the 5 5th day they indulged in a thorough bath, an activity seldom observed in later life. The first moult started after 90 days, at first only slowly on the shoulders and flanks, and was completed by about the 150th day. Except for the pointed tail-feathers, sub-adult females are almost indistinguishable from the adult; in males, however, immaturity is indicated not only by the previously mentioned pale rufous spots on the pointed rectrices, but also by the fact that in the moult although the upper tail-coverts are normally replaced by pale slate blue ones, some of them can retain pale rufous apical edges. However, this has been seen not only in the subadult, but even in a three-year old male. Adults moult once a year in March-April; there is practically no difference between the post-breeding and nuptial plumage, except that th
Size: 1842px × 1357px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishornithologistsclub, bookcentury1900, bookcollec
