Official Organ of the Royal Australasian Ornithologists' Union. 



Birds of z>. feziiber. 



Vol. XX.] isx JULY, 1920. [Part i. 



Plumage Changes of the Nankeen Night^Heron 

 (Nycticorax caledonicus). 



By C. F. Cole, R.A.O.U., Wangaratta, Victoria. 



My chivi uljjt'ct in keeping this species in captivity from nestlings 

 to well o\'ei" the adult stage was for the purpose of observing and 

 recording the plumage changes that take place during each moult. 

 Apart from the plumage question, I found these birds very inter- 

 esting. Their habit of standing whilst seeking for prey in the 

 twilight around the edge of a pool or dish of water, apparently 

 motionless, with the body slightly bent forward and the head 

 downwards, gazing with an expression of alertness^ combined 

 with cunning in their large nocturnal eyes, led the observer to 

 wonder \\'hether these birds have mesmerical powers. 



There is a supposed aboriginal legend attached to the white 

 'nuchal plumes which adorn the head of the adult bird. These 

 birds are supposed, whilst seeking in the shallow water for food, 

 to allow the plumes to rest upon the surface, thus attracting their 

 aquatic prey within reach of their bill. This is purely mythical. 

 These birds are not adorned throughout the whole year with such 

 plumes. Like the Egrets, they cast and grow their plumes at a 

 certain season of the year. 



The attitude of this bird towards others of the feathered tribe 

 in captivity is a very pugnacious one. 



W'hilst undergoing the first moult, which begins to take place 

 within 10 months from leaving the nest, there develops upon the 

 nape four to five dark feathers, not so black as those upon the 

 crown. Down the centre of each of these feathers is a golden- 

 brown streak, which makes them very conspicuous. - JBy tht- 

 end of the second season's moult these feathers disappear, and 

 the white nuchal plumes begin to make their appearance. These 

 striped nape feathers indicate the position of the nuchal plumes. 



After the end of the third year's moult the nuchal plumes attain 

 perfection, and the bird has also acquired full adult plumage. 

 The average total length of the nuchal plumes is 6-| inches, and 

 the colour is pure white streaked at the basal ends with pale brown. 

 These plumes fit one within the other, resembling one long 

 tubular-shaped feather. 



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