174 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



peak of nest building and egg laying in late April and early May. Nests 

 are situated from 2 to 20 m off the ground in trees or, rarely, large 

 shaded shrubs; the average height of the 19 nests Skutch found was 

 about 7 m. The bulky, cup-shaped nest, made almost exclusively of 

 beard-lichen (Usnea), with a small amount of cobweb or caterpillar 

 silk to bind the lichens together, is placed in the fork of an erect branch 

 or in a stout horizontal limb, where upright twigs provide support. 

 Males seem to choose the site and begin construction, although they are 

 soon joined by their mates, and together are intensely active in bringing 

 material to the nest — Skutch watched one pair that made 42 visits in an 

 hour. The finished nest has dimensions of 114-127 mm in overall di- 

 ameter, 50-64 mm height, 57-64 mm diameter of the cavity, and 41 mm 

 cavity depth. 



Egg laying begins 2 to 4 days after construction is finished; the two 

 eggs that form a complete clutch are laid a day apart. Skutch describes 

 them as "long-ovate and rather pointed, and the shells are without much 

 gloss. The ground color is pale gray, of a shade that almost matches 

 the bed of lichens on which the eggs lie. On this gray background, 

 blotches and spots of shades of dark brown and pale lilac are variously 

 distributed. Often there is a distinct belt of heavy brown pigment 

 around the thickest part of the egg." The measurements of 10 eggs 

 averaged 25.8 X 17.2 mm. 



Incubation is done exclusively by the female and lasts 16 or 17 days, 

 during which time she is frequently fed by her mate, although she also 

 leaves the nest often to feed herself. At hatching the nestlings have a 

 distinctive plumage of short, compact tufts of whitish down arranged 

 in narrow rows surrounded by large bald areas. By the age of 9 days 

 their eyes are open and contour feathers are beginning to expand on 

 most parts of the body; in addition, secondary down now covers much 

 of the upper surface that was bare at hatching. The young are fed 

 several times an hour by each parent. In their first few days of life 

 they receive an almost exclusively insect diet; later more fruit is brought 

 to them, although they continue to be fed insects as long as they are in 

 the nest. At 16 or 17 days of age they begin climbing about beyond the 

 edge of the nest, but not until 23-25 days do they fly more than a few 

 feet and leave the nest altogether, after which they are still attended for 

 several days. By early June they can catch insects by themselves. 



Skutch found that of the 15 nests for which he knew the outcome, 4 

 successfully produced fledglings. From the others the eggs or nestlings 

 vanished, possibly taken by Blue-throated Toucanets (Aulocorhynchus 

 caeruleogularis) or Brown Jays (Psilorhinus morio) . 



