Territory in Bird Life
![Territory in Bird Life](/img/big/02/04/89/2048907.jpg)
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Оглавление
Henry Eliot Howard. Territory in Bird Life
Territory in Bird Life
Table of Contents
PREFACE
SCIENTIFIC NAMES OF BIRDS. MENTIONED IN THE TEXT
TERRITORY IN BIRD LIFE
CHAPTER I
INTRODUCTION
CHAPTER II
THE DISPOSITION TO SECURE A TERRITORY
CHAPTER III
THE DISPOSITION TO DEFEND THE TERRITORY
CHAPTER IV
THE RELATION OF SONG TO THE TERRITORY
CHAPTER V
THE RELATION OF THE TERRITORY TO THE SYSTEM OF REPRODUCTION
Footnote
CHAPTER VI
THE WARFARE BETWEEN DIFFERENT SPECIES AND ITS RELATION TO THE TERRITORY
CHAPTER VII
THE RELATION OF THE TERRITORY TO MIGRATION
Footnote
INDEX
PRINTED BY OLIVER AND BOYD, EDINBURGH, SCOTLAND
Отрывок из книги
Henry Eliot Howard
Published by Good Press, 2021
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Our difficulty in estimating the importance of the various factors that make for success or failure arises from our inability to see more than a small part of the scene as it slowly unfolds itself. The peculiar circumstances under which these cliff-breeding forms dwell does, however, enable us to picture, on the one hand, the precarious situation of an individual that was incapable of winning or holding a position at the accustomed breeding station, and, on the other, the plight of the species as a whole if each one exercised authority over too large an area. With the majority of species it is difficult to do this. So many square miles of suitable breeding ground are inhabited by so few Reed-Buntings that, even supposing certain members were to establish an ascendency over too wide an area, it would be impossible to discover by actual observation whether the race as a whole were being adversely affected. Competition doubtless varies at different periods and in different districts according to the numerical standing of the species in a given locality and according to the numerical standing of others that require similar conditions of existence; at times it may even be absent, just as at any moment it may become acute. These examples show how profoundly the evolution of the breeding territory may have been influenced by relationships in the inorganic world, and they give some idea of the intricate nature of the problem with which we have to deal.
I mentioned that the first visible manifestation of the revival of the sexual instinct was to be found in the movements undertaken by the males at the commencement of the breeding season. Such movements are characterised by a definiteness of purpose, whether they involve a protracted journey of some hundreds of miles or merely embrace a parish or so in extent, and that purpose is the acquirement of a territory suitable for rearing offspring. They are thus directly related to the territory, and the question arises as to whether their origin may not be traced to such relatedness. So long as we fix our attention solely upon the magnitude of the distance traversed the suggestion may seem a fanciful one. Nevertheless, if the battles between males of the same species are directly related to the occupation of a position suitable for breeding purposes, if those which occur between males of closely related forms can be traced to a similar source, if the females take their share in the defence of the ground that is occupied, if, in short, the competition is as severe as I believe it to be, and is wholly responsible for the strife which is prevalent at the commencement of the breeding season—then such competition must have introduced profound modifications in the distribution of species; it must have even influenced the question of the survival of certain forms and the elimination of others; and since the powers of locomotion of a bird are so highly developed it must have led to an extension of breeding range, limited only by unfavourable conditions of existence.
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