4 THE AUKS 



that of the adult in summer. In the autumn the teleoptyle dress is assumed, 

 which resembles that of the winter dress of the adults, but the feathers of the throat 

 have faint dusky mottlings. [w. P. p.] 



2. Distribution. In the British Isles this species is found breeding wherever 

 cliffs and steep rock faces afford sites for breeding colonies, both on the mainland 

 and on isolated stacks, and in some districts, such as the great range of chalk cliffs 

 from Speeton to Bempton in Yorkshire, and in various parts ~of the Welsh, Scotch, 

 and Irish coasts, enormous numbers may be found breeding close together. Out- 

 side the British Isles it is found in Iceland and the Faeroes, on Helgoland, Bornholm, 

 Store-Carlso, and Gotland, and along the Scandinavian coast up to the Varanger 

 Fjord, while it is said also to have bred in the E. Murman coast. Southward it 

 occurs on the northern and north-western coasts of France, and eggs have been 

 obtained on the Berlengas Isles, off the coast of Portugal. On the American side it 

 is found from New England and Nova Scotia north to lat. 80, while an allied form 

 inhabits the North Pacific. The winter range of this bird extends to about lat. 30 

 in the Atlantic, but it is scarce in the Western Mediterranean. [F. c. B. J.] 



3. Migration. The remarks on the razorbill under this head apply equally 

 to this species. A guillemot " ringed " as a chick on the Aberdeenshire cliffs in 

 July 1910 was shot near Gothenburg on November 29 of the same year (Aberdeen 

 University Bird-Migration Inquiry). [A. L. T.] 



4. Nest and Eggs. The guillemot makes no nest, but lays its single egg 

 on a bare shelf of rock, generally whitewashed with the droppings of the birds, 

 on a steep cliff face. At the Fame Islands vast numbers nest on the top of the 

 Pinnacles, packed so tightly together that movement is impossible. The egg is 

 very large, and pyriform in shape, and the incubating bird pushes it between 

 her legs, with the pointed end projecting forwards, and sits usually with her back 

 to the sea. (PI. xxxix.) In colour and markings these eggs probably vary more 

 than those of any other species, but can be classified under eight heads, according 

 to the ground-colour, which varies from pure white to creamy, yellow, or deep 

 blue-green. Sometimes eggs are met with entirely devoid of markings, others are 

 spotted or blotched, and in many cases an elaborate system of interlacing lines 

 covers the shell. These markings also vary in colour from rich red to brown, 

 deep black, or some shade of dirty green, and in some cases they practically cover 

 the shell and conceal the ground-colour altogether. (PI. G.) Average size of 122 

 eggs, 3-04 x 1-94 in. [77'37 x 49-45 mm.]. Incubation, which is carried on by both 

 sexes, lasts from 30 to 33 days, according to experiments with an incubator 



