156 Mr. W. Eagle Clarke on the 



young in down. The latter is densely clothed in short down 

 resembling fur, the upper parts of which are mouse-grey, 

 passing into pale whitish grey on the head and cheeks ; the 

 hind-neck is tipped with white and the lores are blackish. 

 The under surface is drab-grey, paler in the centre of the 

 abdomen j the chin and throat are blackish. Bill black. 

 Feet yellowish. Wing 4'9 inches. Culmen 1*4 inches. 

 Tail-feathers 1*5 inches. (See figure Plate IV.) 



Young in Down and Feathers (Eillium Island, Feb. 22nd, 

 1904-). — Has blue-grey feathers on the lower back, tail, sides 

 of the back, and on the edge and tip of the wing; a band 

 of blackish feathers on the crown and hind-neck ; lores 

 feathered black, and the rest of the upper surface covered 

 with mouse -grey down. Under parts with pure white 

 feathers on the abdomen, lower breast, and chin ; upper 

 breast and neck in whitish down with a dusky band across 

 the throat, under which the characteristic black ring or 

 bridle is in evidence. Wing 63 inches. Culmen 135 inches. 

 (See figures Plate IV.) 



Immature Birds in First Plumage resemble the adults, 

 from which they only differ in having the back almost 

 entirely blue, i. e. shewing little black. Here, again, this 

 species differs from its congeners, which have more or less 

 pronounced colour-characters associated with their first 

 plumage. 



Adults. — The old birds on their arrival in spring (November) 

 have the blue and black of the upper surface very bright in 

 tint, but as summer advances (February) the blue fades 

 and the black assumes a broAvnish hue. In February, too, 

 some are in deep moult, the under dowu shews through the 

 scanty covering of contour-feathers, the feathers on the wings 

 are ready to drop off in patches, and the birds are quite 

 tailless. In March and April the new plumage has been 

 assumed, with the exception of the tail-feathers, which are 

 still quite short, and yet these are the first to be assumed by 

 the otherwise downy young. The wing in the adult males 

 measures from 7*1 to 75 inches, and in females from 6*75 to 

 7 "2 inches. 



