60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



across, lined with twigs, leaves, and grass stems. Freshly deposited 

 eggs were noted here on another visit on January 23, 1944. Hallinan 

 (Auk. 1924, p. 306) recorded nests with eggs (Dec. 5, 1915) "on a 

 rocky, wooded islet about ^ mile off shore" from Taboguilla, evi- 

 dently Farallon Rock. The two additional sets collected by General 

 Meyer were taken April 23, 1944, on Isla Pachequilla, from nests 

 that were depressions in the ground on the level summit of the island. 

 Some were in the open, others among bushes and low trees. In 

 some the depression was partly lined with twigs. The six eggs 

 measure in length 57.9-64.4 and in breadth 38.7-41.8 with an average 

 size of 61.2x40.1 mm. 



Near Isla Galera I saw immature birds alight on the water and 

 thrust their heads repeatedly below the surface. I could determine 

 no reason for this, unless possibly they were feeding on plankton. 

 Three adult males taken here at 8 :30 in the morning seem to have 

 left their sleeping quarters recently, as in all the stomach was empty. 



This is the booby most often seen in Panamanian waters, as it out- 

 numbers the blue-footed booby, S. n. nebouxii, and is far more 

 abundant than the Caribbean representative of the species. 



SULA DACTYLATRA Lesson: Blue-faced Booby; Boba Borrega 



Adult white, with black tail. 



Description. — Length 750 to 850 mm. Adult, white, with wing 

 feathers, greater wing coverts, and tail black; bare face and throat 

 dark blue. 



Immature, upper surface, head, and neck, dark brown, becoming 

 paler on breast, and whitish on abdomen. 



This booby, largest of the species of the family reported from 

 Panamanian waters, is known there only from a few sight ob- 

 servations. It has been reported from both coasts so that two sub- 

 species are concerned, but the records need verification by specimens. 

 The two geographic races that should occur differ in size, the supposed 

 color differences in bill and foot color being those that distinguish 

 male and female. 



Iris yellow; bare skin of face black; bill orange-yellow at base 

 in males, light red in females, distally horn color in both sexes; 

 tarsus and toes olive-drab in males, plumbeous in females. (From 

 Murphy, Oceanic Birds S. Amer., 1936, pp. 846, 848.) 



SULA DACTYLATRA DACTYLATRA Lesson 



Sula dactylatra Lesson, Traite Orn., livr. 8, July 11, 1831, p. 601. (Ascension 

 Island, South Atlantic Ocean.) 



Larger in size. 



