but no doubt grim-tragedy from the point of view of the wrens;
a cow-bird with a wren's egg in its beak running rapidly along the walk
with the outraged wrens forming a procession behind it, screaming,
scolding, and gesticulating as only these voluble little birds can.
The cow-bird had probably been surprised in the act of violating the
nest, and the wrens were giving her a piece of theirs minds.

Every cow-bird is reared at the expense of two or more song-birds.
For every one of these dusky little pedestrians there amid the grazing
cattle there are two more sparrows, or vireos, or warblers, the less.
It is a big price to pay--two larks for a bunting-two sovereigns for
a shilling; but Nature does not hesitate occasionally to contradict
herself in just this way. The young of the cow-bird is
disproportionately large and aggressive, one might say hoggish.
When disturbed it will clasp the nest and scream, and snap its beak
threateningly. One hatched out in a song-sparrow's nest which was
under my observation, and would soon have overridden and overborne the
young sparrow, which came out of the shell a few hours later, had I not
interfered from time to time and lent the young sparrow a helping hand.
Every day I would visit the nest and take the sparrow out from under
the pot-bellied interloper and place it on top so that presently it was
able to hold its own against its enemy. Both birds became fledged and
left the nest about the same time. Whether the race was an even one
after that, I know not.

I noted but two warblers' nests during that season, one of the
black-throated blue-back and one of the redstart,--the latter built
in an apple-tree but a few yards from a little rustic summer-house
where I idle away many summer days. The lively little birds, darting
and flashing about, attracted my attention for a week before I