ECOLOGY OF THE HOATZIN BEEBE. 539 



FOOD. 



The hoatzin is imqiiestionably a vegetarian, and the remains of the 

 previously mentioned four-e3ed fish in the crop of one of my Venezue- 

 lan specimens must have been evidence of an abnormal diet. 



Examinations of the stomachs of individuals from various locali- 

 ties show that two or three species of marshy plants furnish almost 

 the entire menu of this bird. One is the mucka-mucka or arum 

 {Montrlchardia arborescens) ^ a tall plant of spindly growth, with 

 large, tough, heart-shaped leaves, and a pineapplelike 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 man- 

 grove (Arvicemiia nitkla). Bates (3) includes the sour guava 

 {Psidium) and " various wild fruits" in his list of its food. 



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, although appar- 

 ently so flimsy in construction, yet are remarkably cohesive. The 

 nests are almost indistinguishable from those of the " Chows " or 

 Guiana green herons {Butondes striata)^ which were built in the 

 same situations. The latter were usually placed low over the water, 

 while the hoatzins were higher, from 5 to 12 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 sup- 

 ported 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 num- 

 bered, respectively, 2, 3, and 4. From what information I could 

 gather, 2 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 Ciuclad 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." 



In Venezuela the last of March the birds were not nesting, and 

 those examined showed no signs of a recent breeding season. In 

 mid- April in British Guiana the hoatzins were just beginning to nest. 



