320 Wonders of the Bird World 



or four days he has found that all these eggs have dis- 

 appeared, others, newly-laid, being in their places. 



The Screaming Cow-bird {Molothrus riifoaxillaris) is a 

 resident species in the neighbourhood of Buenos Ayres, 

 along with the Bay-winged Cow-bird {M. badius), and the 

 latter is victimized by the former species, while, as Mr. 

 Hudson remarks, it will never allow the other Cow-bird 

 (y]/. boiiariensis) to approach its breeding-place. The nest 

 of the Lenatero or Firewood-gatherer {see p. 21 1) is often 

 seized upon by the Bay-winged Cow-birds, and the above- 

 named naturalist relates the story of one of these nests upon 

 v/hich the Gatherers had been employed all the winter, till 

 it had become a bulky structure about twenty-seven inches 

 deep, and from sixteen to eighteen inches in circumference. 

 When thus nearly finished it was visited by a couple of 

 Cow-birds, and the female critically examined the nest, as 

 if she was the one who had given orders for its erection. A 

 few sticks were re-arranged by her, others thrown out, and 

 a general air of proprietorship maintained, which culminated 

 in an attack on the rightful owners and the narrow escape 

 of the female bird from death. Later on the Lehateros re- 

 occupied their nest, but the Cow-birds proved too strong for 

 them, and ultimately it passed into the possession of the 

 latter, who threw out all the young ones and opened a new 

 road into the interior of the nest. Then two Screaming 

 Cow-birds (M. riifoaxillaris) appeared on the scene, and 

 were apparently much interested in the nest. On climbing 

 up to the latter Mr. Hudson found, to his surprise, that it 

 contained ten eggs, instead of five, as he had expected. 

 These could not have been the eggs of the Argentine Cow- 

 bird, the third species of the district, as the Bay-wings 

 would never allow them to lay in it. Three times Mr. 

 Hudson took away the eggs, and on the fourth occasion 

 seven eggs were once more found, instead of the normal 

 five which a Cow-bird lays, and hence it was evident that 



