Dr. Jenner gives us the following anecdote: "I found one day the nest
of a hedge-sparrow, which contained a cuckoo's and three
hedge-sparrow's eggs. The next day, I found the bird had hatched, but
the nest now contained only one sparrow, and the cuckoo. What was my
astonishment to observe the young cuckoo, though so newly hatched, in
the act of turning out the young hedge-sparrow! The mode of
accomplishing this was very curious. The little animal, with the
assistance of its rump and wings, contrived to get the bird on its
back, and, making a lodgment for the burden, by elevating its elbows,
clambered with it to the side of the nest till it reached the top,
where resting for a moment, it threw off its load with a jerk, and
quite disengaged it from the nest. It remained in this situation a
short time, feeling about with the extremities of its wings, as if to
be convinced that the business was properly done, and then dropped into
the nest again."