Fig. 45 

 Distribution of the Sandwich (Cabot's) tern, Thalasseus sandvicensis. Black 

 lines embrace breeding range; black dots are some sight or specimen 



records. 



are placed (artificially) too close together, a dominant female on one 

 nest will rob a neighbouring nest by rolling the eggs from it into her 

 own; but she is unable successfully to hatch more than the normal 

 clutch against her brooding patch. Coition, which takes place on the 

 nest, continues after egg-laying, but it slows down, and the male 

 may rest for longer periods on the back of the female and finally step 

 down without actual consummation. He appears to be an anxious 

 and fussy husband, displaying vigorously as he brings fish to feed his 

 sitting mate; but she also feeds him when he takes his turn on the 

 nest. As in other sea-birds mutual display continues, in lessening 

 degree, during the incubation and fledging periods. 



The eggs are much like those of the gulls, with ground-colour 

 varying from pale grey to a dark brown, streaked and spotted with 

 still darker greys and browns. Blue eggs, with or without markings, 

 occur, but the erythristic type is not common. The incubation period 



