GUILLEMOTS, RAZORBILL, ETC. 127 



respect. During the breeding period some species 

 resort to lofty cliffs washed by the sea ; others 

 burrow into the ground. Many species make no 

 nest whatever, but others form slight structures in 

 which to deposit their eggs. The young of the 

 Auks are hatched covered with down, assuming 

 their first plumage in a few weeks. Adult Auks 

 moult in September ; the difference in the colour 

 of the plumage peculiar to the pairing season, 

 apparently being entirely due to a change in the 

 hue quite irrespective of a moult. The complete 

 change from white to brownish -black observed 

 prior to the breeding season on the necks and 

 heads of Guillemots and Razorbills is very curious 

 and interesting. According to the observations of 

 Herr Gatke, the shafts of the feathers are the first 

 portions in which the black appears ; yet almost 

 at the same time this colour is seen in the form 

 of minute specks on the lower third of the feathers, 

 quickly spreading into crescentic markings, and 

 ultimately covering the entire surface. Half a 

 dozen species are British. Of these, four breed 

 more or less abundantly in our area, and the other 

 two are irregular winter visitors. The now extinct 

 Great Auk the largest known representative of 

 the family formerly bred in certain parts of the 

 British Islands, but, alas, is now only known as 

 a fast receding tradition. We will now proceed to 

 a short study of these British Auks. 



