j3 99 .] 



Patten. — Nest of Little Tern. 



J 95 



surrounding shingles were not suitable for "lining" purposes, 

 the shells being either too large and entire or badly shaped. 

 Indeed it is quite evident that the Ljttle Tern exercises a 

 certain amount of choice as to the materials with which it will 

 line its nest, small fragments of Myidcc and Caidiidcz (Razor 

 and Cockle valves) being special favourites. 



Before proceeding further, it is convenient at this stage to 

 indicate in a tabulated manner the total number of nests 

 observed duiing a period of successive years. From these the 

 average number of nests, constructed like the type already 

 described, may be calculated. Such nests may conveniently 

 be termed "typical," whether in the unfinished or finished 

 state. In the first column the letters N.T. will signify the 

 total number of nests observed on such and such a year. In 

 the second column, U.T. stands for the number out of these 

 which conformed to the unfinished type which has been 

 described. F.T.Z., in the third column, shows the number of 

 " Finished Typical" nests with Zone out of the total number, 

 and A.T., in the last column, stands for " Average Typical" 

 number of nests, taking finished and unfinished examples 

 together : — 



Tabular view of the total number ofuests of the Little Tern (Sicnia 

 minnta) observed at Dollymount, near Dublin, from the )ear 1891 to 

 1899, inclusive, showing also the average number of "typical" nests: — 



