A CONTRIBUTION TO THE LIFE-HISTORIES OF THE BOOBY (SULA 

 LEUCOGASTRA) AND MAN-O'-WAR BIRD (FREGATA AQUILA). 



By Frank M. Chapman. 



INTRODUCTORY. 



The expedition on which the observations herein recorded were made 

 was undertaken primarily to secure specimens, accessories, photographs, and 

 data to be used in the preparation of a " habitat group " of the booby and 

 man-o'war bird in the American jMuseum of Natural History. Dr. Alfred 

 G. ]\Iayer, in command. George Shiras, 3d, and the writer, sailed from 

 Nassau, March 31, 1907, aboard the Physalia, for Cay Verde, about 230 

 miles to the southeast, where the birds desired were reported to nest. Unfa- 

 vorable weather prolonged our voyage to the cay to nine days, and this delay, 

 in connection with continued unpleasant weather and the absence of a harbor, 

 made it undesirable to remain at the cay longer than was necessary for the 

 accomplishment of our object. While, therefore, the trip was successful 

 so far as collections for groups were concerned, the three days and nights 

 (April 9 to 11) passed on the cay permitted us to make only the most 

 casual study of the habits of the birds found nesting there. Nevertheless, 

 with the cooperation of Dr. Mayer and Mr. Shiras, information was 

 gathered which appears to deserve record as a contribution to our knowledge 

 of Bahaman bird-life, and particularly to the biographies of the man-o'-war 

 bird and booby, about the nesting habits of which, in this region, little ap- 

 pears to have been written. 



CAY VERDE. 



Cay Verde lies on the eastern edge of the Columbus Bank, 30 miles 

 southeast of Little Ragged Island. It is about 0.5 mile long by 0.25 mile 

 in greatest width, the longer axis lying approximately north and south, and, 

 roughly estimated, contains some 40 acres. On the west and south, or shal- 

 low, Bank sides there are steeply shelving beaches, where, under favorable 

 conditions, a landing may be easily made ; on the eastern side the dec])-blue 

 waters of the ocean break directly against the characteristic, water-worn 

 limestone rock, of which Cay \^erde, in common with other Bahama islands, 

 is composed. At the northern end, where the islet terminates in a point, 

 this rock is but little above sea-level. Southwartl it gradually increases in 



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