74 WHAT MR. DARWIN SAW. 



ARGENTINE REPUBLIC. 



tentots to be a nest bird." I understand that the male emu 

 in the London Zoological Gardens takes charge of the nest: 

 this habit, therefore, is common to the family. 



THE CASARITA. 



THE casarita (little housebuilder) as the Spaniards call 

 it, from its resemblance to the casara (housebuilder or oven- 

 bird), makes its nest at the bottom of a narrow cylindrical 

 hole, which is said to extend horizontally to nearly six feet 

 under ground. Several of the country people told me that 

 when boys they had attempted to dig out the nest, but had 

 scarcely ever succeeded in getting to the end of the passage. 

 The bird chooses any low bank of firm sandy soil by the 

 side of a road or stream. Here (at Bahia Blanca) the walls 

 round the houses are built of hardened mud, and I noticed 

 that one, which enclosed a court - yard where I lodged, was 

 bored through by round holes in a score of places. On ask- 

 ing the owner the cause of this, he bitterly complained of 

 the little casarita, several of which I afterward observed at 

 work. It is rather curious to find how unable these birds 

 must be to get any idea of thickness, for although they were 

 constantly flitting over the low wall, they kept on vainly 

 boring through it, thinking it an excellent bank for their 

 nests. I do not doubt that each bird, as often as it came 

 to daylight on the opposite side, was greatly surprised at 

 the marvellous fact. 



