304 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



The nests remaining from year to year are utilized by tlie birds at successive 

 nesting periods ; whether or not by the same pair can not with certainty be 

 answered at present. Ou account of tiiis utilization of the old nest from year 

 to year some of the oldest nests have grown to enormous size, due to the addition 



of new materials at each successive season. 



Professor Watson (1908) made an interesting series of observa- 

 tions on the methods of nest building and the daily routine of activi- 

 ties during this period, but I shall attempt to quote only part of 

 what he says about it : 



Both birds work, bringing sticlis, seaweed, shells, and coral. Both birds shape 

 the nest clumsily by pecking and pulling at the sticks. They never weave the 

 sticks so as to form a compact and durable nest. The stick is dropped on the 

 rim, then drawn into position. Frequently first one bird then the other sits in 

 the nest and shapes it. In order to do this, the bird rises on its feet and de- 

 presses its breast and turns round and round. The material is obtained both 

 far and near. Floating sticks and seaweed are gathered from the water. They 

 frequently alight under the nests of other birds and gather up the fallen 

 branches. They even take the material from other nests which are left mo- 

 mentarily unguarded. Frequent fights ensue. The birds work neither steadily 

 nor rapidly ; 10, 15, 20 minutes may elapse before either makes a trip. 



The male feeds the female while she is building the nest, conse- 

 quently it is necessary for him to cease from his labors in assisting her 

 and absent himself in search of food. During his absence she also 

 ceases her activities, but remains at the nest to guard it from her pil- 

 fering neighbors and to repel the advances of other males. On his 

 return she is fed as follows : 



The male returns with a full-laden crop. He alights directly upon the nest 

 or near the female. The female at once shows signs of life, and as they ap- 

 proach each other they beginning nodding. Then the male invites the female 

 to feed by putting his beak down to a position convenient to her. She gets the 

 food by taking it directly from the mouth of the male, the male disgorging it 

 by successive muscular contractions of the throat and abdomen. The impres- 

 sion one gets from this ludicrous performance is that the bird Is choking to 

 death. During the whole of the process of feeding, a soft, nasal, rattling purr 

 is emitted, presumably by the female. This purring sound is an invariable indi- 

 cation that feeding is taking place. It is to be heard on no other occasion. 



Professor Watson (1908) noted the first eggs on May 4 and found 

 that the majority were laid between the 11th and the 16th. He says 

 further : 



After the egg is laid a marked change appears in the behavior of both the 

 male and the female. The birds will now attack even a human intruder, and 

 their defense of the nest against their own kind becomes even more strict than 

 before. Oftentimes the birds will sit on the egg and allow themselves to be 

 caught, striking viciously all the while with their long, keen, pointed beaks. 

 Individuals vary greatly in this respect. On my daily rounds, as I approached 

 the vicinity of a group of nests, several noddies would usually advance to meet 

 me, striking viciously at my head. Their attacks would continue until I 

 withdrew. Many times I have had my hat knocked off and the blood brought 

 from my scalp by their vicious attacks. 



