The Descent of Man

informs me that three kestrels (Falco tinnunculus),
all males, were killed one after the other
whilst attending the same nest; two of these
were in mature plumage, but the third was in
the plumage of the previous year. Even with
the rare golden eagle (Aquila chrysaetos), Mr.
Birkbeck was assured by a trustworthy gamekeeper
in Scotland, that if one is killed, another
is soon found. So with the white owl (Strix
flammea), "the survivor readily found a mate,
and the mischief went on."
White of Selborne, who gives the case of the
owl, adds that he knew a man, who from believing
that partridges when paired were disturbed
by the males fighting, used to shoot them;
and though he had widowed the same female
several times, she always soon found a fresh
partner. This same naturalist ordered the sparrows,
which deprived the house-martins of
their nests, to be shot; but the one which was
left, "be it cock or hen, presently procured a