362 CHAPTERS ON THE NATURAL HISTORY 



and of these I have personally made careful copies, exhibiting 

 them in the present connection in Figs. 89 and 90 : 



"Another and smaller species of Farnarius (F. cunicularius)," 

 says Darwin, in continuation of what I have quoted above, " re- 

 sembles the Oven-bird in the general reddish tint of its plumage, 

 in a peculiar shrill, reiterated cry, and an odd manner of running 

 by starts. From its affinity, the Spaniards call it Casarita (or 

 little housebuilder), although its modification is quite different. 

 The Casarita builds 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 suc- 

 ceeded 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 inclosed a court- 

 yard where I lodged, was bored through by round holes in a 

 score of places. On asking the owner the cause of this, he bit- 

 terly complained of the little Casarita, several of which I after- 

 ward observed at work. It is rather curious to find how incap- 

 able these birds must be of acquiring any notion of thickness, 

 for although they were constantly flitting over the low wall, they 

 continued vainly to bore 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 mar- 

 velous fact." 



One can easily imagine how much an instance of this nature 

 must have interested Mr. Darwin, who was so constantly em- 

 ployed in search of facts to illustrate the various grades of rea- 

 son as exemplified in all kinds of animals. 



Numerous other naturalists besides Darwin have written about 

 these wonderfully interesting oven-birds of South America, ;m<l 

 special reference may be made to the works of Durnford, Hudson, 

 Gibson, Burmeister, and Dorbigny. Each or any of these may be 

 read with profit and interest. As Professor Newton tells us, 

 however, the figures of the nests of Furnarius are, as a rule, very 

 poor indeed; that is, apart from the one here reproduced, which 

 was presented to the Cambridge Museum, of England, by Mr. J. 

 Young. 



In concluding this chapter I am prompted to say I hope it will 

 at least have the effect of inciting its readers who, either 



