BIRDS IN THE CALENDAR 
heron is, particularly in the vicinity of a 
preserved trout stream, the more costly 
neighbour. Indeed it is the only other bird 
which nests in colonies of such extent, but 
there is this marked difference between herons 
and rooks, that the former are sociable only in 
the colony. When away on its own business, 
the heron is among the most solitary of birds, 
having no doubt, like many other fishermen, 
learnt the advantage of its own company. 
One of the most remarkable habits in the 
rook is that of visiting the old nests in mid- 
winter. Now and again, it is true, a case of 
actually nesting at that season has been 
noticed, but the fancy for sporting round the 
deserted nests is something quite different 
from this. I have watched the birds at the 
nests on short winter days year after year, 
but never yet saw any confirmation of the 
widely accepted view that their object is the 
putting in order of their battered homes for 
the next season. It seems a likely reason, 
but in that case the birds would surely be 
seen carrying twigs for the purpose, and I 
never saw them do so before January. What 
other attraction the empty nurseries can 
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