19 1 8.] On the Ornithology of Cape San Antonio. 363 



XXII. — Further Ornithological Notes from the Neighbour- 

 hood of Cape San Antonio, Province of Buenos Ayres. 

 Part I. Passeres. By Ernest Gibson, M.B.O.U., F.Z.S. 



(Text-figures 3 & 4.) 



Introduction. 

 As it is nearly forty years since I wrote my first notes on 

 this subject (Ibis, 1879, p. 405), I may be justified in re- 

 capitulating and extending the preface regarding the exact 

 locality referred to, and the nature of the terrain. The 

 former is important, for, as Mr. Claude H. B. Grant 

 remarks (Ibis, 1911, p. 81) :— '^t is a very interesting- 

 locality, inasmuch as it is about the southern limit of 

 many woodland species common at Buenos Ayres and to 

 the northward, and is about the northern limit of many 

 Patagonian species that migrate northward in the winter 

 months.-" The topographical details are, in their turn, 

 worthy of attention, bearing in mind the unique conjunc- 

 tion of the Atlantic Ocean and the estuary of the River 

 Plate (totally dissimilar in their elementary and coastal 

 formations) : the mainland, or " Campo,'' of pure Pampean 

 origin ; the indigenous or natural woods of the littoral ; 

 and tidal creeks and salt lagunes, which again merge into 

 and lose themselves in immense freshwater swamps and 

 small lakes. 



The smaller map (text-figure 3) establishes the exact 

 geographical position, the larger one (text-figure 4) the 

 physical features of my " Happy Hunting-ground," though 

 without attempting to delineate in detail the labyrinth of 

 salt-water creeks which characterize the northern or River 

 Plate side, or to depict the maze of swamps and marshes 

 on the remainder of the land, principally towards the 

 southern end. 



The Gibson ^'Yngieses'' estancia or stock-farm is now 

 approaching its centenary. When I last wrote from it, in 

 1878, its large extension of 65,000 acres was unfeuced and 



