MIGRATION OF SWALLOWS. 
295 
recurs, — what is the peculiarity of economy which leads 
one species of bird to conceal its nest with the most 
extraordinary care and address, and another to place its 
offspring’ in the most exposed situation it can select ?” — 
Richardson . 
18 . HIRUNDO FULVA , VIEILL. 
THE REPUBLICAN, OR CLIFF SWALLOW. 
AUDUBON, PLATE LXVIII. 
In his account of this species, Audubon has the fol- 
lowing observations on the migration of swallows : — 
“ Being extremely desirous of settling the long agitated 
question respecting the migration, or supposed torpidity 
of swallows, I embraced every opportunity of examining 
their habits, carefully noted their arrival and disappear- 
ance, and recorded every fact connected with their 
history. After some years of constant observation and 
reflection, I remarked, that among all the species of 
migratory birds, those that remove farthest from us, 
depart sooner than those which retire only to the 
confines of the United States; and, by a parity of 
reasoning, those that remain later return earlier in the 
spring. These remarks were confirmed, as I advanced 
towards the southwest, on the approach of winter ; 
for I there found numbers of warblers, thrushes, &c. in 
full feather and song. It was also remarked, that the 
Hirundo viridis of Wilson, (called by the French of 
Lower Louisiana, Le Petit Martinet a ventre blanch) 
remained about the city of New Orleans later than any 
Mher swallow. As immense numbers of them were 
seen during the month of November, I kept a diary of 
the temperature from the third of that month, until the 
arrival of Hirundo purpjrea . The following notes are 
taken from my journal; and as I had excellent oppor- 
tunities, during a residence of many years in that 
country, of visiting the lakes to which these swallows 
were said to resort, during the transient frosts, I present 
them with confidence ? 
“ November 11. — Weather very sharp, with a heavy 
white frost. Swallows in abundance during the whole 
