BIRDS 



245 



On Wenman this Sula was very abundant and the nesting season here, 

 from the thirteenth to the twenty first of December, was somewhat more 

 advanced than we found it on Culpepper Island. The birds were nest- 

 ing in considerable numbers on the small, flat topped island lying to 

 the north of the main island. There is no soil on this island and the 

 females deposited their eggs on the flat surface of the rocks. We did 

 not see any nesting on the ledges of the low cliffs forming the sides of 

 the island. No nest is constructed, and generally only one egg is laid 

 by each female. On Culpepper we saw some nests containing two. 

 They snap their beaks viciously at the foot or leg of the intruding 

 person, and a nesting bird cannot be forced to leave her egg. Even 

 those that are not nesting can scarcely be made to fly. The birds are 

 extremely noisy. When approached they utter loud, harsh, squawk- 

 ing sounds, which become louder and more rapid the more they are 

 disturbed. They utter also a sort of whistling sound made appar- 

 ently in the lower part of the throat while the mouth is held wide 

 open. This whistle is generally preceded by a blowing sound. 

 Birds with eggs make no sounds different from those made by others. 

 One bird when annoyed by poking it with a stick uttered only the 

 loud squawking, while another, disturbed in the same manner, uttered 

 only the whistling notes and could not be induced to make any other 

 sound. Generally, however, the same bird made both of the sounds, 

 changing at short intervals from one to the other. The squawking 

 sound is the one most commonly uttered. 



MEASUREMENTS OF ADULT SPECIMENS OF Sula Variegatd. 



A bird just out of the egg and not yet having its eyes open, was ob- 

 served lying squirming on the ground, uttering in slow succession 

 low chuckling notes. There was no apparent reason why it should be 

 making these sounds. 



Two sets of two eggs each were taken on Culpepper. In color they 

 Proc. Wash. Acad. Sci., January, 1904. 



