324 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



or set between rocks or against a fallen log. The nest is oven shaped 

 and constructed of fine herbaceous stems, grass blades, fragments of 

 dead leaves, rootlets, and other fine plant material. The bottom is a 

 thick pad of finely shredded bast fibers. One nest measured 12 cm high, 

 12 cm from back to front, and 14 cm from side to side. The inside 

 measurements were 6 cm high, 1 1 cm from front to back, and 7 cm from 

 side to side. 



All the nests in which Skutch found eggs contained a clutch of three. 

 Those from one set were white, marked with fine specks of cinnamon 

 crowded over the thicker end and more sparingly scattered over the rest 

 of the surface. They measured 17.9x14.3, 17.5x14.3, and 17.5x14.3 

 mm. Incubation is performed only by the female; Skutch could not 

 determine the length of the incubation period. The young are born 

 with yellow mouth cavities and sparse gray down on pink skin. They 

 are fed by both parents, who bring them insects including long green 

 caterpillars. In one nest the feathers of the young were expanding 

 rapidly at 8 days of age and at 12 days, when their upper surface was a 

 uniform dark gray without head markings and their undersurface yel- 

 lowish olive, the young left the nest. 



Two females collected in Panama by Strauch (Bull. Brit. Orn. Club, 

 1977, p. 64) weighed 10.1 and 11.8 g. 



BASILEUTERUS RUFIFRONS ACTUOSUS Wetmore 



Basileuterus delatrii actuosus Wetmore, 1957, Smiths. Misc. Coll., 134 (9), p. 92. 

 (Isla Coiba, Panama.) 



Characters. — Bill larger and coloration darker than that of B. r. 



mesochrysus. 



Measurements. — Males (11 from Isla Coiba), wing 57.6-62.5 (60.1), 

 tail 51.1-55.8 (53.3), oilmen from base 13.3-14.4 (13.8), tarsus 20.5- 

 22.5 (21.3) mm. 



Females (5 from Isla Coiba), wing 56.1-60.2 (57.5), tail 50.0-53.5 

 (51.8), culmen from base 13.5-13.9 (13.6), tarsus 20.0-21.6 (21.0) 

 mm. 



Resident. Common on Isla Coiba, off the Pacific coast of Veraguas. 

 In January 1956 I encountered birds near the shoreline and back 

 through high forest in the interior of the island. They also came into 

 thickets in abandoned fields near the work camps. They were common, 

 but of secretive habit, keeping behind cover. As they frequently carry 

 their tail at an angle over the back, they often suggest wrens as they 

 move about behind the screening twigs and leaves. At this season they 

 were silent except for an occasional chipping call. Usually they are 



