58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I07 



material studied, birds from the Hawaiian group (Laysan, Gardiner, 

 Necker, Nihoa, French Frigate, Johnson Islands) have the smallest 

 measurements, with those to the south having progressively larger 

 measurements, with the exception of the Marquesas form. Hartert 

 (Nov. ZooL, vol. 34, 1927, p. 18) finds that in G. a. rothschildi the 

 exposed culmen does not exceed 38 mm. and the wing does not 

 exceed 245 mm. My findings agree with these ; however, measurements 

 of birds from Wake, Guam, Rota, and Saipan are almost identical 

 with those of the Hawaiian birds with the maxima and minima very 

 similar. Birds from the Caroline Islands (Ulithi, Truk, and Kusaie), 

 as shown in the table, average larger in size, and there is no great 

 amount of overlap in wing length. Whether or not the Caroline 

 Islands birds are distinct, as supposed by Hartert when he named 

 G. a. kittlitzi, can only be learned when a large series of birds from 

 more southern localities are studied. The presence of the distinct race 

 in the Marquesas Islands offers further evidence that other separable 

 forms may be present. It seems apparent from this study that the 

 Hawaiian race, G. a. rothschildi, is not sufficiently distinct to be 

 separated by name from populations at Wake and in the Marianas. 



At Guam, white terns were numerous and distributed in all parts 

 of the island, especially in the coconut groves. Birds were found 

 breeding during the spring months. A downy young first observed 

 in a banyan tree on March 27 began to fly on April 17. Most of 

 the birds collected in May, June, and July were in molt. One of the 

 two birds collected at Rota in October was in molt. Weights of nine 

 adult males from Guam are 97-119 (108), of six adult females 100- 

 116 (108). Weights of two adult males from Rota are 115 and 124. 



At Ulithi Atoll, terns were abundant. There was apparently a peak 

 in nesting activity in April, May, and June, service personnel report- 

 ing a number of very young birds at that time. The eggs were placed 

 in limb forks of breadfruit trees. One recently hatched downy young 

 was collected at Bulubul Island on August 21. Six of eleven adults 

 taken at Ulithi in August were in molt. At Truk and the Palau 

 Islands, white terns were numerous in coconut groves. Stomachs of 

 birds taken at Ulithi and Peleliu contained fish, insects, and marine 

 crustaceans. 



The back of a juvenile male (collected September i) from I'eleliu 

 Island is barred with bands of near "mummy brown" and light buff. 

 The coloring extends to the scapulars, innermost secondaries, and 

 upper wing-coverts and to the crown and occiput, where the coloring 

 is more mottled than barred. The feathers of the sides of the neck have 

 some brownish edges. An adult female, taken at Guam on May 23 



