FAMILY ICTERIDAE 



339 



scrawls and other irregular markings partly overlaid by shell so that 

 they vary from dull chocolate and dull cinnamon to faint purple; it 

 measured 43.8x26.3 mm. Three eggs measured by Skutch averaged 

 38.1x24.3 mm. 



These oropendolas are sometimes parasitized by the Giant Cowbird 

 (Scaphidura oryzivora) . Although they attempt to drive the intruders 

 out of their nest tree, a few cowbirds inevitably succeed in depositing 

 an egg. Only some of the female oropendolas recognize the egg as 

 foreign and remove it. 



The incubation period is 17 or 18 days (Smith, Nature, vol. 219, 

 1968, p. 692) and the young remain in the nest approximately 30 days, 

 during which time they are fed fruit. When they emerge, the young 

 are quite large and able to fly a few hundred yards, even though they 

 have never before had space to stretch their wings. The young are im- 

 mediately led from the conspicuous and isolated nest tree to the safety 

 of the forest. 



This species and P. guatimozinus have often been separated in the 

 genus Gymnostinops. 



PSAROCOLIUS GUATIMOZINUS (Bonaparte): Black Oropendola, 

 Chacarero Negro 



Ostinops guatimozinus Bonaparte, 1853, Compt. Rend. Acad. Sci. Paris, 37, p. 833. 

 (Garrapata, middle Rio Magdalena, near Malena, Antioquia, Colombia.) 



Very large; few feathers of central crown elongated, forming a thin 

 crest; all black except for dark chestnut scapulars, lower back, upper 

 tail coverts, and abdomen, and bright yellow tail; particolored bill. 



Description. — Length, male 464-481 mm, female 387-396 mm. Adult 

 (sexes alike except for size), entire body black except middle of back 

 to upper tail coverts, abdomen, and undertail coverts dark chestnut, 

 darkest on rump and upper tail coverts; wing coverts dark chestnut, 

 remiges black; central pair of rectrices black, shorter than others, 

 which are bright yellow; underwing coverts black. 



A male collected January 31, 1964, at Pucro, Darien had the iris 

 light wood brown; swollen cheek patch deep clear blue; bare skin be- 

 hind eye paler blue; lower edge of lores like cheek patch; bare forehead 

 reddish orange, changing to orange from most of center; top of bill 

 orange-red; rest of bill black; top of tongue pale gray; inside of mouth 

 black except for tip, this orange-red, shading distally to yellowish on 

 mandible; bare skin on side of throat dull red, bordered narrowly by 

 bluish white, this color extending on either side of central feathering 

 inside rami; tarsus and claws black; underside of toe pads dull yellow, 



