8l4 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



ter of 1869 I saw three of them skimming over the plain on one of the 

 coldest days I have ever experienced, the thermometer having stood at 29° 

 Fahr. the preceding evening. But 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 pass- 

 ing 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 after- 

 wards 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 re- 

 luctantly when approached, and some allowing me to stand within 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 (September 22) 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, 

 oi i\\.t S&ndiitro [A mmibius aciiiicaudatns). . . . 



" It is, however, under the eaves of houses that these Swallows prin- 

 cipally breed ; and there is not a house on the pampas, however humble it 

 may be, but some of these birds are about it, sportively skimming over and 

 about the roof or curiously peering under the eaves and incessantly utter- 

 ing their gurgling, happy notes. Indeed their fondness for being close to 

 a house is so remarkably strong that in their longest excursions they are 

 seldom more than five minutes absent from it. 



" For a month or six weeks before they begin to build, they seem to 

 be holding an incessant dispute ; and however many eligible chinks and 

 holes there may be, the contention is always just as great among them, 

 and is doubtless referable to opposing claims to the best places. When 

 these troubles and feuds are finally ended, they address themselves dili- 

 gently to their work, and build a rather large nest. They are not neat or 

 skilful workers, but merely stuff a great quantity of straw and other light 

 material into the hole they build in, and line it thickly with feathers and 

 horsehair. The eggs are white and pointed, from five to seven in 

 number. . . . 



" They have a habit which cannot but be grateful to the mind of every 



