Potts. — New Zealand Birds. 205 



dull flesh colour. Males of the same age present no observable contrast in 

 their plumage to that of the other sex. When this shag is about a year old 

 the membranous processes, which are such conspicuous features, gradually lose 

 their former texture, and become coarsely granulated ; dark green spots are 

 sparingly dotted on the wing-coverts, the throat assumes a darker hue, the 

 white shafts of the tail feathers are exchanged for rectrices with shafts of slaty 

 black, the two centre feathers are the first to be replaced ; tarsi and feet take 

 a more decided tinge of yellow. In all these changes there is a remarkable want 

 of constancy, so that to note down all the variations that may be observed in 

 an extensive series would exceed all reasonable limits for such a paper as this. 

 In the nuptial plumage this common bird becomes one of the handsomest 

 of our sea-fowl, the great and striking alteration conferred by snow-white 

 accessary plumes that decorate the head lasts but a short time in perfection in 

 either sex, and gradually moults away into the more sober garb of the summer 

 plumage. In the month of August adult birds have the head greenish brown, 

 sparingly interspersed with narrow white feathers, immediately above the 

 forehead rises a tuft of dark brownish green feathers, while another of the 

 same shade forms a long irregular crest just above the nape ; this inclines 

 forward, reminding one of a clown's toupet ', on either side a line of snow- 

 white feathers, more or less produced, extends from above the eye to the wing, 

 meeting in a broad band below the nape; upper surface brownish grey, 

 marked with deep green spots ; back deep glossy black-green j throat blackish 

 green ; under surface, leaden grey j lower abdomen, tail, and thighs deep 

 glossy black green j thighs often sprinkled with narrow white plumes, which, 

 like those on the head and neck, are of temporary duration ; mandibles, horn 

 colour ; lore, bluish purple, the eye circlet of torquoise blue j chin greenish, 

 often bluish purple, deepest at the point ', tarsi and feet yellow. 



Summer plumage, November ; Head, neck, and upper surface dark greenish 

 grey ; wing-coverts and scapulars, dotted with deep green spots j throat and 

 neck pale grey, mottled with dull green ; under surface leaden grey 3 lower 

 abdomen black green ; rectrices black. 



Measurements. In. Lines. 



Bill from gape to point ... ... ... ... 3 4 



Tarsus ... ... ... ... ... 2. 5 



Wing ... ,,. ... ... ... 9 2 



Length ... ,,. ... ..*. ... 28 



Average weight of adult birds may be fairly estimated at 2 lbs. 1 3 ozs. 

 When this bird is cruising in search of prey its long neck is often moved 

 from side to side, reminding one of the habits of the nearly allied Plotince ; 

 this is observable too in the young nestlings ; of some species of Plotince it is 

 said that the neck is always in oscillation. 



