1920.] Cape San Antonio, Buenos Ayres. 13 



shorter grass again. Unlike the first nest, no jiinco entered 

 into its composition ; only very fine small dry grass and 

 rootlets, forming a monnd tliirty inches in diameter at the 

 base, the cup-shaped cavity being about a foot across and 

 lined with much down. The fine and maximum clutch of 

 nine eggs was much incubated. With the exception of the 

 down-lining, it will be noticed that these three nests differ 

 in materials and structure, though the choice and conditions 

 were identical for all the birds. From each nest two or 

 three paths led through the grass to the water fifty yards 

 away, the nests being in the centre, and highest part, of the 

 island. The parent birds kept at a distance of three or four 

 hundred yards, swimming about and occasionally uttering 

 their alarm-cry,'^ 



. Lastly comes the class of nest which I may designate as 

 the ''truncated cone '^ formation; which is exemplified in 

 the following account of a colony of no less than seventeen 

 pairs of Swans : — The winter of 1913 had been one of 

 heavy rains, culminating in the flood which reached its 

 highest level at the end of September, when two- thirds 

 of my land was submerged. All the low ground between 

 the Yngleses and the woods of the Real Viejo had dis- 

 appeared below the sea of water, and only the tops of the 

 higher rushes showing above the surface indicated the 

 position of the great cahadons. In consequence, all sheep 

 had been rafted-out in August, and the cattle M'ithdrew 

 themselves to the mainland ; whilst, naturally, there re- 

 mained no incentive for the stockinen to make their usual 

 rounds of inspection. At the end of^ovember the gradual 

 subsidence of the flood had left in one particular locality an 

 extensive flat of mud, shallow water, and a small island or 

 two. With a clear survey of half-a-mile or a mile on each 

 side, and surrounded by our biggest and deepest caiiadons, 

 it would be difficult to imagine a more secluded and suitable 

 situation for a breeding-haunt of the Coscoroba Swan. 

 The actual date (21 November) is a late one ; but I take 

 it that the magnitude of the flood, submerging all other 

 possible breeding-sites, retarded the usual nesting-period. 



