es that fringe the pool, to hinder us from obtaining a panoramic
view of the whole proceedings, and moreover the area occupied by each
individual is comparatively small. Towards the middle of February,
symptoms of sexual organic change make themselves apparent, and the pool
is then no longer the resort of a peaceable community; quarrels become
frequent, and as different portions of the surface of the water are
gradually appropriated, so the fighting becomes more incessant and more
severe. Each individual has its own particular territory, embracing a
piece of open water as well as a part of the rush-covered fringe, within
which it moves and lives. But in the early part of the season, when the
territories are still in process of being established, and definiteness
has still to be acquired, trespassing is of frequent occurrence, and the
conflicts are often conspicuous for their severity.

Now these conflicts are not confined to unpaired individuals, nor to one
sex, nor to one member of a pair--every individual that has settled upon
the pool for the purpose of breeding will at one time or another be
involved in a struggle with its neighbour. If then we single out certain
pairs and day by day observe their actions and their attitude towards
intruders, we shall notice that, instead of their routine of existence
consisting, as a casual acquaintance with the pool and its inmates might
lead us to believe, of an endless series of meaningless disputes, the
behaviour of each individual is directed towards a similar goal--the
increasing of the security of its possession; and further, if we pay
particular attention to the circumstances which lead up to the quarrels
and the circumstances under which such quarrels come to an end, we shall
find, when we have accumulated a sufficient body of observations, that
the disputes always originate in trespass, and that hostilities always
cease when the trespasser returns again to its own territory. By careful
observation it is possible to make oneself acquainted with the
boundaries--I know not what other term to use--which separate this
territory from that; and it is the conduct of the birds on or near these
boundaries to which attention must be drawn. A bird may be feeding
quietly in one corner of its territory when an intruder enters. Becoming
aware of what is happening it ceases to search for food, and approaching
the intruder, at first swimming slowly but gradually increasing its
pace, it fin