236 THE BIRDS OF THE BRITISH ISLES. 



The colour of the eggs (Plate 94) varies greatly ; some are 

 pale, greenish or buff, others deep brown in ground, and the 

 marks of black, brown, or grey may be speckles, spots, or 

 blotches ; some are thickly zoned with markings, others have 

 a black or brown patch at the larger end. It is practically 

 impossible to distinguish between the eggs of the Common and 

 Arctic Tern. Three is the usual number, but clutches of two 

 are common ; only a small proportion are hatched. Out of 

 some 300 nests in one Lancashire colony, Mr. F. W. Holder 

 found only eight from which all three chicks emerged. Eggs 

 and nestlings are destroyed by rats, weasels, and stoats at 

 night, but diurnal robbers get a warm reception. Most eggs 

 are laid in June. The nestlings have been described as 

 dimorphic ; polymorphic is more correct ; the down varies 

 from grey to deep brown, sandy buff is most usual ; the black 

 markings and mottles are irregular. Some have white, others 

 black chins : they may grow paler with age. The bill is light 

 red or almost black, the legs salmon-pink, reddish, or yellow. 

 The nestlings are fed by the parents on small fish — sand-eels, 

 dabs, and coal-fish fry being common. I have seen the old bird 

 drop the fish, but I think unintentionally ; Saunders thought 

 that food was deliberately dropped in front of the nestling, 

 but it is usually delivered to the young, when the old bird, with 

 wings uplifted, daintily alights beside it. One of the dropped 

 fish was the venomous lesser weever. The young (Plate 106), 

 which follow their parents with repeated insistent cries, chik^ 

 cJiik, chik^ are at first much mottled with buff and slate on the 

 upper parts, and their foreheads are buff, but after the autumn 

 moult the forehead is white, the crown speckled, and the nape 

 brownish black ; the back and mantle are then marked with 

 grey and buff, and the shoulders show a greyish band. The 

 bill is almost black, and the legs dull red. The mature bird 

 has a black cap, pearl-grey back and wings, primaries edged 

 with dark grey, and a white tail with greyish borders to the 



