Territory in Bird Life

CHAPTER VII. The Relation of the Territory to Migration 259

THE RELATION OF THE TERRITORY TO MIGRATION 259

INDEX 302

LIST OF ILLUSTRATIONS

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A pair of Lesser Spotted Woodpeckers attacking a Great Spotted Woodpecker Frontispiece

Territorial flight of the Black-tailed Godwit 54

Competition for territory is seldom more severe than among cliff-breeding seabirds, and the efforts of individual Razorbills to secure positions on the crowded ledges lead to desperate struggles 64

Male Blackbirds fighting for the possession of territory. The bare skin on the crown of the defeated bird shows the nature of the injuries from which it succumbed 74

Male Cuckoos fighting before the arrival of a female 82

Two pairs of Pied Wagtails fighting in defence of their territories 86

Long-tailed Tit: males fighting for the possession of territory. The feathers have been torn from the crown of the defeated and dying rival 96

A battle between two pairs of Jays 106

The Female Chaffinch shares in the defence of the territory and attacks other females 110

Peregrine Falcon attacking a Raven 216

A battle between a pair of Green Woodpeckers and a Great Spotted Woodpecker for the possession of a hole in an oak-tree 238

Plans of the Water-meadow showing the Territories occupied by Lapwings in 1915 and 1916 Between 58 and 59

SCIENTIFIC NAMES OF BIRDS MENTIONED IN THE TEXT

Raven Corvus corax.

Carrion-Crow Corvus corone.

Hooded Crow Corvus cornix.

Rook Corvus frugilegus.

Magpie Pica pica.

Jay Garrulus glandarius rufitergum.

Chough Pyrrhocorax pyrrhocorax.

Starling Sturnus vulgaris.

Greenfinch Chloris chloris.

Hawfinch Coccothraustes coccothraustes.

House-Sparrow Passer domesticus.

Chaffinch Fringilla coelebs.

Brambling Fringilla montifringilla.

Linnet Acanthis cannabina.

Corn-Bunting Emberiza calandra.

Yellow Bunting Emberiza citrinella.

Cirl Bunting Emberiza cirlus.

Reed-Bunting Emberiza schoeniclus.

Sky-Lark Alauda arvensis.

Pied Wagtail Motacilla lugubris.

Tree-Pipit Anthus trivialis.

Meadow-Pipit Anthus pratensis.

Great Titmouse Parus major newtoni.

Blue Titmouse Parus coeruleus obscurus.

Long-tailed Titmouse Ægithalus caudatus roseus.

Red-backed Shrike Lanius collurio.

Whitethroat Sylvia communis.

Lesser Whitethroat Sylvia curruca.

Blackcap Sylvia atricapilla.

Grasshopper-Warbler Locustella noevia.

Savi's Warbler Locustella luscinioides.

Reed-Warbler Acrocephalus scirpaceus.

Marsh-Warbler Acrocephalus palustris.

Sedge-Warbler Acrocephalus schoenobænus.

Willow-Warbler Phylloscopus trochilus.

Wood-Warbler Phylloscopus sibilatrix.

Chiffchaff Phylloscopus collybita.

Song-Thrush Turdus musicus clarkii.

Redwing Turdus iliacus.

Blackbird Turdus merula.

Redstart Phoenicurus phoenicurus.

Redbreast Erithacus rubecula melophilus.

Nightingale Luscinia megarhyncha.

Stonechat Saxicola rubicola.

Whinchat Saxicola rubetra.

Wheatear OEnanthe oenanthe.

Hedge-Sparrow Accentor modularis.

Wren Troglodytes troglodytes.

Spotted Flycatcher Muscicapa striata.

Swallow Hirundo rustica.

Martin Delichon urbica.

Sand-Martin Riparia riparia.

Great Spotted Woodpecker Dryobates major anglicus.

Lesser Spotted Woodpecker Dryobates minor.

Green Woodpecker Picus viridis.

Cuckoo Cuculus canorus.

Tawny Owl Strix aluco.

Buzzard Buteo buteo.

Sparrow-Hawk Accipiter nisus.

Peregrine Falcon Falco peregrinus.

Merlin Falco æsalon.

Kestrel Falco tinnunculus.

Shag Phalacrocorax graculus.

Wild Duck Anas boschas.

Snipe Gallinago gallinago.

Dunlin Tringa alpina.

Ruff Machetes pugnax.

Redshank Totanus totanus.

Black-tailed Godwit Limosa limosa.

Curlew Numenius arquata.

Whimbrel Numenius phæopus.

American Golden Plover Charadrius dominicus.

Lapwing Vanellus vanellus.

Oyster-Catcher Hæmatopus ostralegus.

Herring-Gull Larus argentatus.

Kittiwake Rissa tridactyla.

Razorbill Alca torda.

Guillemot Uria troille.

Puffin Fratercula arctica.

Fulmar Fulmarus glacialis.

Water-Rail Rallus aquaticus.

Corn-Crake Crex crex.

Moor-Hen Gallinula chloropus.

Coot Fulica atra.

Wood-Pigeon Columba palumbus.

Turtle-Dove Streptopelia turtur.

Partridge Perdix perdix.

Black Grouse Lyrurus tetrix britannicus.

Red Grouse Lagopus scoticus.

TERRITORY IN BIRD LIFE

CHAPTER I. Introduction

INTRODUCTION

In his Manual of Psychology Dr Stout reminds us that "Human language is especially constructed to describe the mental states of human beings, and this means that it is especially constructed so as to mislead us when we attempt to describe the working of minds that differ in a great degree from the human."

The use of the word "territory" in connection with the sexual life of birds is open to the danger which we are here asked to guard against, and I propose, therefore, before attempting to establish the theory on general grounds, to give some explanation of what the word is intended to represent and some account of the exact position that representation is supposed to occupy in the drama of bird life.

The word is capable of much expansion. There cannot be territories without boundaries of some description; there cannot well be boundaries without disputes arising as to those boundaries; nor, one would imagine, can there be disputes without consciousness as a factor entering into the situation; and so on, until by a simple mental process we conceive of a state in bird life analogous to that which we know to be customary amongst ourselves. Now, although the term "breeding territory," when applied to the sexual life of birds, is not altogether a happy one, it is difficult to know how otherwise to give expression to the facts observed. Let it then be clearly understood that the expression "securing a territory" is used to denote a process, or rather part of a process, which, in order to insure success to the individual in the attainment of reproduction, has been gradually evolved to meet the exigencies of diverse circumstances. Regarded thus, we avoid the risk of conceiving of the act of securing a territory as a detached event in the life of a bird, and avoid, I hope, the risk of a conception based upon the meaning of the word when used to describe human as opposed to animal procedure.

Success in the attainment of reproduction is rightly considered to be the goal towards which many processes in nature are tending. But what is meant by success? Is it determined by the actual discharge of the sexual function? So many and so wonderful are the contrivances which have slowly been evolved to insure this discharge, that it is scarcely surprising to find attention focused upon this one aspect of the problem. Yet a moment's reflection will show that so limited a definition of the term "success" can only be held to apply to certain forms of life; for where the young have to be cared for, fostered, and protected from molestation for periods of varying lengths, the actual discharge of the sexual function marks but one stage in a process which can only succeed if all the contributory factors adequately meet the essential conditions of the continuance of the species.

Securing a territory is then part of a process which has for its goal the successful rearing of offspring. In this process the functioning of the primary impulse, the acquirement of a place suitable for breeding purposes, the advent of a female, the discharge of the sexual function, the construction of the nest, and the rearing of offspring follow one another in orderly sequence. But since we know so little of the organic changes which determine sexual behaviour, and have no means of ascertaining the nature of the impulse which is first aroused, we can only deal with the situation from the point at which the internal organic changes reflect themselves in the behaviour to a degree which is visible to an external observer. That point is reached when large numbers of species, forsaking the normal routine of existence to which they have been accustomed for some months, suddenly adopt a radical change in their mode of behaviour. How is this change made known to us? By vast numbers of individuals hurrying from one part of the globe to another, from one country to another, and even from mid-ocean to the coasts; by detachments travelling from one district to another; by isolated individuals deserting this place for that; by all those movements, in fact, which the term migration, widely applied, is held to denote. Now the impulse which prompts these travelling hosts must be similar in kind whether the journey be long or short; and it were better, one would think, to regard such movements as a whole than to fix the attention on some one particular journey which fills us with amazement on account of the magnitude of the distance traversed or the nature of the difficulties overcome. For, after all, what does each individual seek? There may be some immature birds which, though they have not reached the necessary stage of development, happen to fall in with others in whom the impulse is strong and are led by them--they know not where. But the majority seek neither continent nor country, neither district nor locality is their aim, but a place wherein the rearing of offspring can be safely accomplished; and the search for this place is the earliest visible manifestation in many species of the reawakening of the sexual instinct.

The movements of each individual are then directed towards a similar goal, namely, the occupation of a definite station; and this involves for many species a distinct change in the routine of behaviour to which previously they had been accustomed. Observe, for example, one of the numerous flocks of Finches that roam about the fields throughout the winter. Though it may be composed of large numbers of individuals of different kinds, yet the various units form an amicable society actuated by one motive--the procuring of food. And since it is to the advantage of all that the individual should be subordinated to the welfare of the community as a whole there is no dissension, apart from an occasional quarrel here and there.

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