86 Mr. E. Gibson on t/ie Oniitholutjy of [Ibis, 



especially on the larger laguuas, where one may frequently 

 see the faQiily-gronp of !^i\ or seven individuals. A most 

 unusual gathering was that described to rae by my collector, 

 F. Roldan, who, on 8 March, 1899, killed six with one shot 

 out of a flock of about a hundred (adults and immature), on 

 a stretch of 0[)en water about half-a-mile long and seventy 

 yards wide, situated in the neighbouring Tuyu estancia. 

 The following summer my diary quotes the species as being 

 " incredibly abundant." 



Further breeding-notes extend the nesting-period largely, 

 through October and November. Three dates are still 

 later — 14 December, 10 January, and 8 February. The 

 species may ])ossibly have two broods in the course of the 

 season, or it ma}'^ be that my collector in each case had 

 despoiled the first nest earlier in the spring. The full 

 clutch of eggs is six or seven, the latter being frequent ; 

 but I do not recollect having seen more than five young 

 accompauying the parent birds. 



Fresh measurements of the eggs corroborate those given 

 previously — an average, say, of 44x31 mm., with consider- 

 able variation in dift'erent clutches and individual cases. 



422. Tachybaptes dominicus Linn. American Dabchick. 

 Male and female. Iris dark brown, pupil black; bill, 



upper mandible dark brown, base and lower mandible 

 yellowish ; feet olive ; those of the male more yellow in 

 tinge. 



The above pair, shot on 13 December, 1898, were identified 

 by Dr. Berg as being of this species, and they now repose 

 in the Buenos Ayres Museum. 



I have only one other record of its occurrence w hen, on 

 25 February, 1900, a pair with young came under my 

 observation. 



423. Podilymbus podiceps Linn. Thick-billed Grebe. 

 Adult male and female. Iris dark brown, in some cases 



with a white ring round the eye ; bill generally plumbeous, 

 at other times pale grey or nearly white, with grey culmeUj 



