THE COMMON GUILLEMOT. 301 



This species lays a single egg on .the bare rock, and 

 incubation lasts about a month ; the eggs vary greatly in 

 colour, scarcely two being exactly alike, but they are gener- 

 ally either bluish-green, blotched or streaked with dark 

 reddish-brown or black, or white with similar markings. 

 The eggs are very good for the table, and also are said to 

 be used for clarifying wine, and for the preparation of patent 

 leather. 1 



After the breeding season is over about the beginning 

 of August the birds leave the cliffs at St. Abb's Head with 

 their young for the open sea, where they are seen dispersed 

 during autumn and winter. They return to the rocks in 

 March, and begin to lay in May. 



The Guillemot flies with a rapid motion of the wings 

 and at great speed, and, when it returns from the sea to the 

 nesting ledges, curves upwards in its flight as it approaches 

 the rock, and thus alights gently. Its flight is straight, and 

 it is a very expert diver. Mr. Seebohm gives the following 

 interesting account of its aquatic gambols in the salt-water 

 tanks at the Brighton Aquarium : " Using their wings much 

 after the manner that a fish does its fins, they progress 

 through the water, darting hither and thither with great 

 rapidity. In swimming the Guillemot uses its legs as a 

 motor, but in diving the wings alone are used The whole 

 body of the bird is covered with a mass of air-bubbles, and 

 it leaves a train of these bubbles behind it, glistening like 

 silver and pearls, which adds much to the beauty of the 

 performance. Sometimes the descent of the bird is perpen- 

 dicular, sometimes in an oblique direction, and its progress 

 under the water is made apparently as easily as through the 

 air; even more so, turning and gliding about with ever 

 graceful movements, and sometimes hovering over a morsel 



i Yarrell's British Birds, fourth edition, vol. iv. p. 71. 



