342 THE STRUCTURE AND LIFE OF BIRDS CHAP. 
prey on wounded birds. He will condescend, too, to 
pick up worms and molluscs, but I do not know that 
he ever catches fish for himself. The Great Skua I 
have never seen upon the warpath. Besides robbing 
Gulls of their fish, he is known to attack and eat 
Kittiwakes and even Gulls of larger size. 
When it is migrating southward, the Arctic Skua 
may often be seen upon our coasts. But it is worth 
while going to Shetland to see both kinds in their 
breeding haunts. <A great part of the day is devoted 
to gyrations in the air, the smaller bird often accom- 
panying its movements with its peculiarly rasping 
twangy note, the greater one croaking less harshly. 
The Great Skua is a bird of majestic flight, ascending 
high, when there is an upward wind off the cliffs, 
in easy spirals without. a motion of the wings. 
Though both birds have a grim look and though they 
live by plundering the weak, a gull who has not just 
caught a fish shows no fear, at any rate of the ‘Arctic 
Skua. There is no panic when he appears, as there is 
among small birds in the presence of a Hawk. 
Nesting Habits of the Rhea. 
The nesting habits of this bird are so remarkable 
that it is difficult to pass them over. The hen lays a 
great number of eggs, so that if she were to leave 
them till she herself could sit upon them, many would 
become addled. Several, therefore, lay in one nest, 
and when a good many have accumulated, a cock bird 
comes and undertakes’ the incubation, and not only 
that, but cares for the young when they are hatched. 
