144 Mr. J. Graham Kerr on the Avifauna 



-/_125. Phalacrocorax brasilianus. (Op. cit. ii. p. 91.) 



Very abundant both on the Parana and the Paraguay, as 

 well as on the lower Pilcomayo. On our boat approaching 

 a party of them in the water^ they would stretch up their 

 necks and watch us suspiciously for a bit ; and then, as we 

 approached nearer^ they invariably took to flight. Also to 

 be seen in large numbers perched on trees by the river's bank, 

 especially towards evening and in the early morning. On 

 the Pilcomayo the Cormorant was the only one of the strictly 

 aquatic birds which was to be found in almost equal numbers 

 all through the dry season, when the waters of the rivers 

 and lagunas had become intensely salt. This species has a 

 powerful flight, and many were to be seen flying high over- 

 head, as if traversing long distances. 



126. Ardea cocoi. {Op. cit. ii. p. 93.) 



Frequent on Rios Parana, Paraguay, Bermejo, and Pilco- 

 mayo. It has a sharp metallic cry resembling the syllables 

 " coc-oi." 



-/ 127. Ardea egretta. {Op. cit. ii. p. 98.) 



Very abundant on the Parana and on the Pilcomayo near 

 its mouth, but, in common with the other Herons, it disap- 

 peared in the dry season. 



.j:,128. Ardea candidissima. {Op. cit. ii. p. 99.) 

 Very abundant on the Parana and the lower Pilcomayo. 



129. Ardea sibilatrix. {Op. cit. ii. p. 100.) 

 (No. 123, ^ .) This Heron, which is occasionally met with 

 on the Pilcomayo, has a clear hard whistle, in quality ap- 

 proaching the metallic note of the Bandurria. Its flight also 

 differs from that of its congeners, the wings being moved 

 through a very small vertical angle and with much more 

 rapidity than is usual. A specimen upon the ground, when 

 I approached, stood bolt upright, its neck and beak stretched 

 straight upwards, its back towards me, and remained abso- 

 lutely motionless. The colour of its back assimilated very 

 closely with that of the surrounding vegetation, so that it was 

 almost invisible. 



