WATERFOWL 
different times been erroneously accepted 
as distinct species and named accordingly* 
The wild duck's nest is usually placed on 
the ground in some sheltered spot close to 
still or running water, and the ducklings 
swim like corks, soon learning the proper use 
of their flat little bills in gobbling up floating 
insects and other waterlogged food. Occa- 
sionally ducks nest in trees and they have 
been known to take possession of a deserted 
rook's nest. There has been some discussion 
as to whether, in this case, the mother conveys 
her ducklings to the water in her bill, but 
this has not actually been witnessed. In 
cases where, as is often observed, the nest 
overhangs the water, it has been suggested 
that the young birds may simply be pushed 
over the edge and allowed to parachute down 
to the surface, as they might easily do with- 
out risk. 
Tame ducks are among the most sociable 
of birds and can even display bravery when 
threatened by a common enemy. The natura- 
list Houssay once learnt this as the result of 
a somewhat cruel experiment that he made 
in order to ascertain whether ducks invariably, 
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