follow one another in ordered sequence. I spoke
of the process as a series of relationships. Some of these relationships
have already been touched upon; others will become apparent if we
consider for a moment the purposes for which the territory has been
evolved. Indirectly its purpose is that of the whole process, the
rearing of offspring. But inasmuch as a certain measure of success could
be attained, and that perhaps often, without all the complications
introduced by the territory, there are manifestly advantages to be
gained by its inclusion in the scheme. The difficulties which beset the
path of reproduction are by no means always the same--all manner of
adjustments have to be made to suit the needs of different species.
There are direct relationships, such as we have been speaking of, which
are essential to the every-day working of the process, and others which
are indirect, though none the less important for they must have
exercised an influence throughout the ages. These latter are furnished
by the physical--the inorganic world, by climate, by the supply of the
particular kind of breeding stations, by the scarcity or abundance of
the necessary food and by the relative position of the food supply to
the places suitable for breeding. Why does the Reed-Bunting cling so
tenaciously to an acre or more of marshy ground, while the Guillemot
rests content with a few square feet on a particular ledge of rock? The
answer is the same in both cases--to facilitate reproduction. But why
should a small bird require so many square yards, whilst a very much
larger one is satisfied with so small an area? The explanation must be
sought in the conditions of existence. The Reed-Bunting has no
difficulty in finding a position suitable for the construction of its
nest; there are acres of waste land and reedy swamps capable of
supplying food for large numbers of individuals, and the necessary
situations for countless nests. But its young, like those of many
another species, are born in a very helpless state. For all practical
purposes they are without covering of any description and consequently
require protection from the elements, warmth from the body of the
brooding bird, and repeated supplies of nourishment. A threefold burden
is thus imposed upon the parents: they must find food for themselves,
they must afford protection to the young by brooding, and they must
supply them with the necessary food at regular intervals. And their
abi