174 WORCESTER. 



Male frigatti birds. Fregaia aquila (Liniiteiis), were flying about with 

 their scarlet throat pouches puffed out like children's toy rubber baloons, 

 and a photograph was secured of a tine male which came down wounded 

 and kept its throat pouch partially inflated. 



Shortly before noon we returned to our steamer taking with us a 

 splendid series of specimens of the frigate bird and of Micra,nous. and 

 also a number of wood rats which were extraordinarily abundant. 



During the hmch hour we ran as near as possible to the Arena Islands 

 of which there are two rising from an extensive shoal. Here we foimd 

 two frigate birds; also a number of brown boobies nesting on the ground. 

 We decided, however, that it was best to return to Cavilli Island and 

 collect carefully selected specimens of frigate birds in order to complete 

 a series showing full)' the immature and adult plumages. 



This we ^^'ere able to do. A wounded bird which fell into the sea near 

 shore served to attract others in large numbers so that we could select 

 our specimens at will. We also obtained a good series of immature red- 

 legged boobies. These birds displayed a great interest in us both when 

 we approached and when we left the island and in several instances 

 attempted to alight upon us or our boat. 



Just before dusk as we were leaving for the steamer we witnessed an 

 extraordinary scene. Large numbers of red-legged boobies which had 

 apparently been fishing all day began to return, bringing fish to their 

 nesting mates and to their young. The frigate birds promptly formed 

 a skirmish line and, singly or in jjairs, attacked all comers, compelling 

 them to give up their fish. Some of the boobies, possibly sophisticated 

 individuals which had learned wisdom by experience, actually handed 

 their fish over to the frigate birds and so escaped withoiit much drubbing, 

 but less experienced or more obstinate individuals which at first refused 

 to disgorge were vigorously punished until they changed their minds and 

 threw up their fish which were most adroitly caught in the air by their 

 piratical enemies. In one instance two frigate birds set upon a booby, 

 one of them attacking him from above and the other flying below to 

 catch the fish which he dropped, and getting five out of seven. Soon the 

 incoming bobbies began to arrive in flocks and the frigate birds were not 

 able to set ujDon them all, so that many individuals got through to the 

 island. Once among the trees they were left in peace. 



A trip should be made to Ca\'illi Island earlier in the season when 

 Mici-anous and possibly also the frigate birds will be found mating. 



On June 23, 1911, I sailed from Manila \\dth Governor-General Forbes 

 and others on a trijj to the Calamianes Islands, Palawan, the Siilu Archi- 

 pelago, and Mindanao. On the evening of June 28 we left Puerto Prin- 

 cesa for Sibutu and Sitanki, and as the weather was unusually calm 

 decided to go by way of Tub-bataha Eeef which I had never previously 

 succeeded in visiting. 



