32 BIRDS OF TIERRA DEL FUEGO 



The Burrowing Owl is quite a feature of the land. It is 

 common in the open country, though nothing like so plentiful 

 as experienced by Darwin in the Argentine Pampas. There are 

 those who say it is becoming extinct in sheep districts where the 

 undergrowth has been eaten down : others believe its numbers 

 are increasing. To me it appeared most numerous where the 

 undergrowth had been eaten off. Yet it is difficult to explain 

 this, for the sheep have almost trampled out Ctenomys^ the 

 mole-like rodent which must formerly have constituted its 

 chief food supply. There remain, it is true, vast numbers of a 

 buff-coloured field mouse (^Rhithrodon) with large ears and eyes 

 and a long tail, and these may suffice. In winter and early 

 spring this Owl preys on rodents ; in summer largely coleoptera, 

 in particular a brown chafer beetle (Aulacojjalpus pilicollis)^ 

 as can be seen from the pelts. 



This Owl is quite as diurnal in habit as nocturnal, or more so. 

 In the day-time, it can always be seen above ground. It flies 

 at one aggressively, screeching, " Chiii-chi-chi-cM-chi.!' circling 

 round, and then alights a short distance away, to await develop- 

 ments. It occurs in pairs. Usually, both birds can be seen 

 above ground, and make common cause against an intruder. 

 In the breeding season I have several times come upon a pair 

 above ground, and one has gone to earth, while the other has 

 remained above to pursue harrassing tactics. 



Azara thus tersely and characteristically describes its ways : — 

 " Habita los campos limpios, no los bosques, y se oculta en 

 las cuevas de los Tatus y Vizcachas. No es arisco, y quando 

 uno se le acerca canta fuerte ' Chm-chi-cM-chi-chi^^ dando un 

 vuelito breve y posandose sobre algun terron, desde donde mira 

 con insolencia al que se le aproxima; pero otras veces, y siempre 

 que tiene miedo, se entra en la cueva, de la qual nunca se aleja." 



D'Orbigny's account is, perhaps, the best of all, and from this 

 I make the following extract : — 



" Chaque couple choisit son canton, ou il s'^tablit pour la 

 vie, ne voyageant pas, et ne permettant guere aux autres de 



