TREE-MARTIN 29 
or tree; and if it be still occupied by the rightful 
owners, after much time has been spent in sporting 
about and reconnoitring it, a feud begins which 
is often exceedingly violent and protracted for 
many days. 
In seasons favourable to them the Oven-birds build 
in autumn and winter, and breed early in spring ; so 
that their broods are out of their clay houses by the 
end of October or earlier; when this happens the 
Swallow that breeds in November quietly takes 
possession of the forsaken fortress. But accidents 
will happen, even to the wonderful fabric of the 
Oven-bird. It is sometimes destroyed and must be 
rebuilt ; or its completion has perhaps been retarded 
for months by drought, or by the poor condition of 
the birds in severe weather; or the first brood. has 
perhaps perished, destroyed by some tree-climbing 
enemy ; a young opossum for instance, less than a 
rat in size, and able to squeeze itself into the nest- 
ing chamber. November, and even December, may 
thus arrive before some pairs have hatched their 
eggs; and it is these unfortunate late breeders that 
suffer the violence of the marauding Swallows. I 
have often witnessed the wars of these birds with 
the deepest interest ; and in many ovens that I have 
opened after the builders had been expelled I have 
found the eggs of the Oven-bird buried under the 
nest of the Swallows. After the Swallows have taken 
up a position near the coveted oven, they occasionally 
fly towards and hover about it, returning again to 
their stand. By-and-by, instead of returning as at 
