three hundred of them in the course of a long walk a little to the north of Buenos 

 Aires. It was quite warm and very fine, not at all like winter. This is the most 

 common Swallow we have, and there is scarcely a ranche in the country that has not its 

 one or two pairs breeding under the eaves or in the cracks of the walls. It also resorts 

 to holes in trees for nesting-purposes. Though during cold and dull weather in the 

 winter none are visible sometimes for weeks together, a warm bright day never fails to 

 attract some from their temporary shelter, wherever that may be. Pretty common at 

 Baradero in April." 



The following account is from the pen of that excellent observer Mr. W. H. 

 Hudson : — 



" The Hinindo leucorrhoa is the most common of our Swallows near Buenos Aires, 

 and in its glossy coat of deep blue and green, with rump and under-plumage snowy 

 white, is an elegant and beautiful bird. They are the last of all the migratory species 

 to leave us in autumn, and invariably reappear in small numbers on every warm day 

 in winter, so that some people do not believe that they leave us at all, but only retire to 

 the more sheltered places when the weather is severe. In the winter of 1869 I saw 

 three of them skimming over the plain on one of the coldest days I have ever ex- 

 perienced ; the thermometer having stood at 29° Fahr. on the preceding evening. Bat 

 those that remain through the winter with us are apparently only a few individuals, while 

 in the autumn myriads are seen passing north in their migration, and some years continue 

 passing for upwards of a month. In April 1869, several days after all the Swallows of 

 our five species had totally disappeared, flights of the kind I am describing began again 

 to appear passing north ; and for ten days afterwards they continued to pass. They 

 would descend to sip water from a pool where I watched them, alighting afterwards 

 on the reeds and bushes to rest. Many of them appeared quite tired with their 

 journey, rising reluctantly when approached, and some allowing me to stand witliin 

 two yards of them without flying. I had never before observed any supple- 

 mentary or later migration like this ; and last autumn (1870) certainly nothing of 

 the kind took place. Probably the migration of this species extends very far south ; 

 at present they are passing in great numbers, and have been so passing for the last 

 fifteen days. 



" They sometimes build in a tree, in the large nest, previously abandoned, of the 

 Seiiatero {Anumhius acuticaudatus). I have had occasion before, and shall have it 

 again in descriptions of other species, to mention that interesting bird and its great 

 nest. 



" It is, however, under the eaves of houses that these Swallows principally breed ; 

 and there is not a house on the pampas, however humble it be, but some of these birds 

 are about it, sportively skimming over and about the roof or curiously peering under 

 the eaves and incessantly uttering their gurgling, happy notes. Indeed their fondness 

 for being close to a home is so remarkably strong that in their longest excursions they 

 are seldom more than five minutes absent from it. 



