844 MR. W. H. HUDSON ON THE [Nov. 19, 



8. Further Observations on the Swallows of Buenos Ayres. 

 By W. H. Hudson, C.M.Z.S. 



[Eeceived August 6th, 1872.] 



I have already spoken in former communications * of all but one of 

 the species of Hirundinidse that visit us in this region ; the bird I have 

 yet to describe is the Atticora cyanoleuca — the Golondrinas timoneles 

 negros of Azara, and the smallest of our Swallows. I cannot say what 

 are the limits of its range, as my wanderings have not extended far 

 in any direction, and I have never yet been in any region where it is 

 not well known. In Buenos Ayres these Swallows appear early in 

 September, coming before the three species of Progne that visit, us, 

 but preceded by the Hirundo leucorrhoa. They are bank-birds, 

 breeding in forsaken holes and burrows (for they never bore into 

 the earth themselves), and are consequently not much seen about the 

 habitations of man. They sometimes find their breeding-holes in the 

 banks of streams, or in peopled districts in the sides of ditches, and 

 down in wells. But if in such sites alone fit receptacles for their 

 eggs were found, the species, instead of one of the commonest, would 

 be rare indeed ; for on the level pampas most of the watercourses 

 have marshy borders, or at the most but low and gently sloping 

 banks. But the burrowing habits of two other animals, the Vizcacha 

 (Lagostomus trichodachjlus) and the Minera {Geositta cunicularia) 

 have every where afforded the Swallows abundance of breeding-places 

 on the plains, even where there are no streams or any other irregu- 

 larities in the smooth surface of earth. 



The Geositta bores its hole in the sides of the Vizcacha's burrows ; 

 and in this burrow within a burrow the swallow lays its eggs and rears 

 its young, and is the guest of the Vizcacha and as much dependent on 

 him as the Wren or the Swallow we call domestic is on man ; so that 

 in spring when this species returns it is in the villages of the Vizca- 

 cha we see them. There they live and spend the day, sporting 

 about the burrows, just as the domestic Swallow does about our 

 houses. The nest, constructed of dry grass lined with feathers, is 

 placed at the extreme end of the burrow, and contains five or six 

 white, pointed eggs. After the young have flown, they sit close 

 together on a weed, thistle-top, or low tree ; and the parents con- 

 tinue to feed them many days. 



As in size and brightness of plumage, so in language also is this 

 Swallow inferior to his congeners, his only song consisting of a single 

 weak, trilling note, much prolonged, which the bird repeats with 

 great frequency when on the wing. But sometimes he utters two 

 notes ; and then the second note, though much the same, is longer 

 and more inflected than the first ; yet his voice has ever a mournful 

 monotonous sound. If a rapacious bird or a Fox chances to intrude 

 upon the burrows when they are breeding, these Swallows summon 

 each other with cries indicative of fear and anxiety ; but even then 



* See P. Z. S. 1871, p. 326, and 1872, p. 605. 



