ALTA MIRA LICHTENSTEIN'S ORIOLE 233 



The wall was thickest at the bottom. Here the material was tightly interwoven 

 and matted. The lining was not attached either to the bottom or to the sides. 

 It could be lifted en masse without difficulty, evidently having been laid with some 

 care and pressed into final position by the bird's body. 



At this, and at all the other nests observed, only one brightly colored 

 bird was ever seen at the nest or even bringing material; as both 

 sexes are brightly colored and practically indistinguishable in the 

 field, this was probably the female. Brief notes on their other nests 

 follow : 



"Sutton discovered a partly built Alta Mira Oriole nest on April 

 6. It was almost directly above one of the paths leading from the 

 Rio Sabinas to the main trail to Gomez Farias and was about 30 feet 

 from the ground on a dead branch in a living tree at the edge of a 

 good-sized clearing. Here one brightly colored bird was noted 

 repeatedly, never two." 



Another nest "overhung the Rio Sabinas not far from the Rancho. 

 We found it on April 3, but we do not know how many birds worked 

 on it. It was in a cypress and must have been fully 50 feet above the 

 water. It was in plain sight for many rods both up and down stream 

 and was not far (possibly 25 feet) from an occupied nest of the Rose- 

 throated Becard (Platypsaris aglaiae) and one of the Giraud, or 

 Social Flycatcher (Myiozetetes similis)." 



The fourth nest "was far out on one of the uppermost branches of a 

 large (50 feet high), completely dead tree that stood quite by itself in a 

 well cleared field just north of the headquarters house"; and the fifth 

 "hung from a leafless, perhaps dead branch, almost over the main 

 highway, about 30 feet from the ground." 



Sutton and Burleigh (1940) found a nest in San Luis Potosi that 

 swung from a single telephone wire that ran above a wooded gully 

 and was 80 or more feet from the ground. The poles were many 

 rods off, on ridges at either side of the gully. Dickey and van Rossem 

 (1938) say that, in El Salvador, "the usual sites are the tips of branches 

 at varying heights from the ground, but sometimes the nests are hung 

 from telephone wires, particularly if there happen to be a few tufts 

 of epiphitic growth to provide a starting point." 



It appears from the above accounts that the Alta Mira oriole pur- 

 posely selects the most conspicuous nesting site that it can find, on 

 which Sutton and Pettingill (1943) comment: 



Certain it is that a conspicuous nest site is advantageous to the owner insofar 

 as it forces enemy species to use exposed avenues of approach. How easy it is, 

 when we focus attention on any one bird to forget that this bird's enemies all have 

 enemies themselves! Any predatory creature that makes its way to an Alta 

 Mira Oriole's nest, either by day or by night, is certain to expose itself to its own 

 enemy species whether these happen to be enemy species of the oriole or not. 



