334 THE SCOTTISH NATURALIST 



constituent, but probably ordinary down is also used, and we 

 know that a varying number of feathers from breast and belly 

 are also present. — Annie C. Jackson, Swordale. 



Black-headed Gull (Larus riditoundus) Breeding while 

 still in Immature Plumage.— On 9th August 19 15 we picked up 

 a female Black-headed Gull, lying dead in Largo Bay. On dis- 

 section we decided that it had bred, but as it was not in fully mature 

 plumage, thought we would like to have expert opinion on the 

 subject, so sent it to Professor L. R. Sutherland, who kindly 

 examined it for us, and writes that the bird " has certainly bred." 

 This interesting specimen still has the immature markings on the 

 wing-coverts, and the dark feathers of the hood are mixed in about 

 equal proportions with white ones. These white feathers are not 

 the white ones of the winter plumage appearing, but are old and 

 worn. One or two of the new winter feathers on the head are just 

 beginning to show, these being still almost wholly in quill. It is 

 interesting to get confirmation of what has been before suspected, 

 namely, that these Gulls may breed before mature plumage is fully 

 assumed. — Evelyn V. Baxter and Leonora Jeffrey Rintoul. 



Spring Moult of Gulls.— With regard to the articles by 

 Blake-Knox in the Zoologist (1866-68), to which Dr Ticehurst makes 

 appreciative reference in the last number of this magazine, it 

 appears to me that their author should be cited as a supporter of the 

 "colour-change" theory rather than of a spring moult in Gulls, 

 except in the case of immature birds, for which he records a partial 

 moult (head and neck chiefly). \\\ his article on the Common Gull 

 we read that "in adult birds" (in contradistinction to immature 

 ones) "the plumage is revivified, rejuvenated, reimpigmented in the 

 spring." Again, describing the "adult in summer (May)," he wrote : 

 " An unseen change, because there has been no moult, has taken 

 place in the whole bird. The plumage has rejuvenated and repig- 

 mented, looking fresh and blooming." There is no dubiety about 

 these statements, and others equally alleging " transmutation " might 

 be quoted. Li the case of the Black-headed Gull it is possible to 

 cite him as favouring the assumption of the hood by a moult in 

 adult as well as immature birds ; but he makes a significant quali- 

 fication. Describing the adult bird, he says : " The hood assumed 

 by moult, though in old birds I have known this change by trans- 

 mutation." It is interesting to find him mentioning with approval 

 Macgillivray's account of the plumages of this Gull to which I 

 referred in a previous note (ante, p. 287). — William Evans, 

 Edinburgh. 



