1909] Beehe: Ecology of the Hoatzin. 59 



my Venezuelan specimens must have been evidence of an ab- 

 normal diet. 



Examinations of the stomachs of individuals from various 

 localities show that two or three species of marshy plants fur- 

 nish almost the entire menu of this bird. One is the mucka- 

 mucka or arum (Montrichardia arborescens) , a tall plant of 

 spindley growth, with large, tough, heart-shaped leaves, and a 

 pineapple-like fruit. The leaves, flowers and fruit are all eaten. 



Hoatzins also feed on the Drepanocarpus lunatus, and, both 

 in Guiana and Venezuela, devour the tough leaves of the White 

 Mangrove {Arvicennia nitida). Bates (3) includes the Sour 

 Guava (Psidium) and "various wild fruits," in his list of its 

 food. 



Part X — Nest and Eggs. 



At the time of our arrival on the Abary the Hoatzins had 

 just begun to nest. They were utilizing old nests which, al- 

 though so apparently flimsy in construction, yet are remarkably 

 cohesive. The nests are almost indistinguishable from those of 

 the "Chows" or Guiana Green Herons (Butorides striata) , which 

 were built in the same situations. The latter were usually placed 

 low over the water, while the Hoatzins' were higher, from five to 

 twelve feet above the surface of the marsh. The twigs were 

 longer and more tightly laced in the Hoatzins' nests, and while 

 the Herons' nests crumbled when lifted from the crotch, the 

 others remained intact. The Hoatzins placed their nests in a 

 crotch of the white-barked trees, or more rarely supported by 

 several branched mucka-mucka stems. Both sexes assist in the 

 building, as we observed two birds collecting and weaving the 

 twigs. Three sets of eggs which came under our observation 

 numbered, respectively, two, three and four. From what in- 

 formation I could gather, two seems to be the usual number. 

 There is no foundation for the assertion that these birds are 

 polygamous. 



There is little accurate data in regard to the date of nesting 

 of Hoatzins. It is possible that it differs in different places, and 

 that no definite limits can be set to cover the species as a whole. 



On the Orinoco, near Ciudad Bolivar, Cherrie (16) records 

 that the nesting season extends from early in June until mid- 

 September, thus including the height of the rainy season. 

 Quelch (38) in British Guiana found the Hoatzin nesting from 

 December to July, and thinks it "very likely that it is continuous 

 throughout the year." 



