Cape San Antonio, Buenos Ayres. 23 
These sites are crannies in the eaves or gables of any build- 
ing, or various similar situations; but the nest is never so 
isolated from some contiguous beam or wall as to necessitate 
its being entirely built of mud, that material being only used 
to close up the open sides and leave but one entrance-hole. 
‘The mud is very coarsely mixed, sometimes with a good deal 
of grass init. The lining consists merely of some dry grass. 
One of their favourite localities is a beam underneath the 
eaves of our large wool-store, just at the doorway. It says 
much for their familiarity that the constant traffic does not 
deter them from building there. 
The eggs are of a beautiful white, pear-shaped, and average 
45x 7§. Six is the largest clutch I have taken. 
27. PROGNE TAPERA. 
This species is probably as abundant as the preceding ; but, 
as a frequenter of the woods and from the nature of its nidi- 
fication, it is more diffused, and consequently appears scarcer. 
It is also about a month later in coming, appearing in the 
first week in October, though it leaves at the same time as 
P. purpurea, the end of March. 
Breeding-Notes.—As it arrives after P. purpurea, it is pro- 
portionately later in breeding, while, from being parasitical 
on Furnarius rufus, the date of its nesting varies greatly. 
Eggs are most generally taken in December; but I once found 
a nestful of young birds (full-fledged, it is true) as late as 
the beginning of March. 
It only breeds in the nests of the Red Oven-bird (Furnarius 
rufus), either taking possession after the original owners have 
hatched out and reared their brood, or forcibly ejecting the 
rightful occupants. Mr. Hudson has been more fortunate 
than I in witnessing the prolonged and determined warfare 
displayed on the latter occasions, an interesting account of 
which he has given in his paper. But he is mistaken in sup- 
posing that this peculiar habit of P. tapera is unique; for 
Leptasthenura egithaloides (Kittl.), as will be seen further 
on, is also parasitical on F. rufus, though it is content to wait 
for a disoccupied tenement. 
