278 



blow either up or down the lake ; and when seeking food, the birds soar against the wind 

 along the margin of the lake on one side, until they reach its extremity, when they at once 

 turn and 



down before the wind to the other end, where they recommence their soaring 

 flight. But the most singular circumstance is that in the main valley they pursue various 

 species of moths, which occur in large numbers amongst the tussock grasses, and especially in 

 sedgy patches occupied by standing water. I could not for some time make out the object of 

 their peculiar flight ; but a friend of mine (Mr. E. W. Fereday, of Christchurch), who was lately 

 on a visit with me for the purpose of collecting the Lepidoptera of the district, whilst pursuing a 

 large moth, observed one of these Gulls swoop at and capture it. We then noticed that some 

 five or six of the birds were busily engaged in feeding on the moths, pursuing them very much as 

 other insectivorous birds would do. The birds which frequent the lake become very tame, one 

 pair in particular readily taking a worm from my outstretched hand, and constantly coming close 

 to the house for food. Nothing can exceed the pureness and delicacy of their plumage when in 

 full feathei-. It is doubtful whether this kind ever visits the sea-coast" *. 



Like the preceding species, the Black-billed Gull deposits its eggs on the bare ground, its 

 attempts at forming a nest being of the rudest kind, a few bents of grass or other dry materials 

 loosely collected round the edges being deemed a sufficient preparation. There are two examples 

 of the egg of this Gull in the Canterbury Museum, both very handsome in appearance, but 

 differing entirely in the style and distribution of their colours. One of these is of a narrow ovoid 

 form, measuring 2-15 inches in length by 1*65 in breadth; it is of a dull yellowish white or pale 

 buff, covered with numerous spots and irregular markings of dark brown ; these markings are 

 more numerous towards the thicker end, forming a broad zone and displaying fantastic shapes 

 not unlike some of the characters in the Chinese alphabet ; and on one side of the egg, com- 

 mencing at the smaller end, there is a large blotch of rich umber-brown, varied with a darker 

 brown, and covering more than half its surface. The other example is somewhat smaller and 

 more rounded in form ; the ground-colour is a delicate greenish grey ; about the middle of the 

 egg there is a narrow belt of a brighter tint of green ; near the thick end there is a broad dark 

 zone formed of obscure inky blotches, varied with irregular markings of blackish brown ; and 

 over the entire surface there are small scattered spots and markings of a rich dark-brown colour. 



■v 



* Trans. New-Zealand Inst. 1871, vol. iv. p. 209. 



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