Reports of Special Agents 



311 



Approximate Number of Noddy Terns. — Since the Noddies build their 

 nests of twigs, moss and sea-shells in accessible places, it is easily possible, with 

 the help of a mechanical counting device, actually to count the number of nests. 

 In some places, where the bay cedar is exceedingly dense, and the area has to 

 be gone over dog fashion (or at times even more primitively), and in others, 

 where the cactus growth is very dense, error in counting is possible. Six hundred 

 and three nests were actually counted. Probably 700 nests (inhabited) would 

 be a safer estimate. Doubling this 

 •count to get the number of birds as 

 before, we have approximately 1,400 

 Noddies on the island. For reasons 

 v\'hich I will admit are not scientific- 

 ally based, I feel that the above 

 figure does not give a sufficient num- 

 ber of Noddies. In the first place, 

 from the general impression one 

 gets, one feels that there is a vastly 

 greater number present. In the 

 second place, there are always hun- 

 dreds of Noddies 'sunning,' either 

 on the beach or in the trees. Now 

 my studies show that, during the 

 brooding season at least, the Noddy 

 has no leisure. Consequently, I feel 

 sure that there are many cases where 

 the birds live on the island without 

 nesting. I venture the suggestion, 

 merely as a suggestion, that the 

 Noddy does not breed until at least 

 two years of age. 



A Running Account of ^Nesting 

 Events. ' — The birds landed upon the 

 island (April 27) five days before I 

 reached it. On May 2, the beginning of my three months' continuous resi- 

 dence there, the birds (both species) were present in large numbers. As Dr. 

 Thompson suggests, mating, apparently, had already taken place before the 

 arrival of the birds upon the island. The Noddies were busily engaged, some 

 in rehabihtating old nests, others in constructing new ones. (The Noddy is 

 never satisfied with its nest, no matter how large it is. A suitable twig, piece 

 of shell, or bunch of moss, is an irresistible stimulus, which sets free the collect- 

 ing movements, regardless of the stage of advancement of the nesting period.) 



The Sooties, at this time, were choosing and 'holding' appropriate nesting- 

 ,sites. This was done only by dint cf persistent fighting. The building of the 



NODDY TERN PORTRAITS 



