v LARIDAE 303 



remainder of the tribe generally collect a mass of grass, moss, 

 flags, sedges, heather, twigs, or sea-weed, though a mere hollow in 

 the soil or sand often serves their purpose. The eggs vary in 

 number from two in the case of the Ivory Gull and the Skuas to 

 three or exceptionally four ; they are brown, drab, or green, with 

 blotches and spots of brown, black, grey, and lilac, and recall those 

 of Plovers. Both sexes have been said to incubate in Larus minutus 

 and Rissa Irevirostris ; the young are comparatively helpless for a 

 few hours or perhaps days, and are at first fed by the parents. 



Terns resemble Gulls in many of their habits, but are more 

 cosmopolitan, and decidedly migratory in Britain; they are 

 essentially marine, yet some species breed on inland waters in 

 summer. Particularly slender and graceful, these long- winged birds 

 may usually be distinguished by their irregular or hovering flight, 

 and are known as Sea-swallows ; while their method of beating 

 up and down maritime streams or shallows, singly or in pairs, 

 in search of fish, is quite peculiar to themselves. At such times 

 they make constant plunges into the water, often completely 

 immersing their bodies, or occasionally discontinue their opera- 

 tions to engage in trivial and seemingly amicable quarrels. The 

 note, though hoarse in some cases, is usually a squealing or 

 grating sound, the latter especially when disturbed ; the food con- 

 sists of fish and crustaceans, insects said to be sometimes taken on 

 the wing frogs, newts, locusts, grasshoppers, caterpillars, leeches, 

 molluscs, and medusae. Terns are wary but bold, commonly 

 circling around a wounded companion until several are shot ; the 

 Noddies (Anous), however, are much more sluggish and silent. On 

 the ground all move with comparative ease. The nest of Hydro- 

 clielidon is a mass of water-weeds placed on some tussock in a wet 

 inland swamp ; that of Anous, when situated on trees, bushes, or 

 rocky ledges, is composed of twigs, sea- weed, and like materials ; 

 but most species merely make a hole in the sand or soil, with little 

 or no lining. Depressions on level rocks, the surface of prostrate 

 plants, and heathery, grassy, or muddy flats are often utilized as 

 alternatives, while colonies are usually formed. Two or three olive, 

 reddish-brown, green, or stone-coloured eggs, with blotches, spots, 

 scrawls, or oblique streaks of black, brown, grey, or lilac, are deposited; 

 the Noddy and Sooty Terns, however, have a single white egg with 

 red markings, and Gygis one, which is buff, marbled, spotted, or 

 often scrolled with brown and grey, and is laid on any slight cavity of 



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