Some aspects of the ecology of the hedgehog (Erinaceus europaeus L.) in the Manawatu, New Zealand: a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University

Copyright is owned by the Author of the thesis. Permission is given for

a copy to be downloaded by an individual for the purpose of research and

private study only. The thesis may not be reproduced elsewhere without

the permission of the Author.

MASSEY UNIVERSITY -

~Ill ^I II llll II

1061368057

I lllll I lllll I II

A THESIS PRESENTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ZOOLOGY AT MASSEY UNIVERSITY.

JOHN PATERSON PARKES. 1972.

ABSTRACT

During the period from

1/1/70

to

24/6/71, 150

hedgehogs were marked and

356

resightings were recorded in a study area covering

16.28

hectares of pasture and trees. Population size and density are estimated and the seasonal changes ⁱⁿ activity are described.

The sex ratio of the population and the apparent changes in this ratio due to behavioural dimorphism between sexes are discussed in relation to the body weights of the anima1s and to hibernation and breeding season. No detailed age structure is presented for the present population.

The breeding season and the number and size of the litters are discussed, as are the causes of mortality in the popu~ation. Dispersal of the population is seen as an important demographic parameter, and the sexual and seasonal influences upon movement are discussed.

Home ranges are investigated using two statistical methods; the convex polygon method and a probability ellipse method. The shape and size of individual's ranges are described using the first method, while the second method is used to describe synthesised ranges for

(,ii)

ma1es, £emales and juveniles. The nest site and £ood locations are discussed in terms of £oci 0£ activity, and seasonal changes in movements were investigated and an argument is advanced on the hedgehog's territorial behaviour and social structure.

(iii)

PREFACE

When choosing a topic within the desired Cield of mammalian ecology, the length and economics of the study meant that certain restrictions had to be applied.

Short studies of mammalian population ecology are usually complicated by the difficulties of catching enough

individuals and the expense of traps. As hedgehogs are numerous in the Manawatu and are easily caught without traps, this species fulfills these two requirements.

Further, the number of mammalian species within the region is limited and the majority of species have been or are being studied more intensively than this thesis allows.

The exception to this was the hedgehog, the last ecological study in New Zealand ^hav~ng been carried out by Brockie

(1958).

An appreciation of the critical assistance and

patience of my supervisor, Dr R.A. Fordham is gratefully acknowledged.

(iv)

TABLE OF CONTENTS

Page

CHAPTER 1 • INTRODUCTION

. .

¹

1.1 Review of Previous Work 1.2 Study Area

1.3 General. Methods

CHAPTER 2. POPULATION STRUCTURE

. .

¹¹

2.1 Popu1ation Size and Density

..

2.2 Seasona1 Changes in Activity 2.3 Body Weights

2.4

Sex Ratio 2.5 Age Structure

CHAPTER

3.

POPULATION DYNAMICS _{• •} 29 3.1 Breeding Season

3.2 Litter Size

3.3

^Mortality

3.4

Dispersal.

(v)

TABLE OF CONTENTS (Cont'd)

CHAPTER 4. HOME RANGE

4.1

Introduction and Statistica1 Methods

4o2 Resu1ts

4.3

Discussion

(i)

Shape of the Home Range

(ii) Size of the Home Range (iii) The Nest as a Focus 0£

Activity

(iv) Food Concentrations as Foci of Activity (v) Seasona1 Changes in

Movement

(vi) Territory and Social Structure

SUMMARY OF RESULTS

. . . . . .

REFERENCES ^{0 • • • • • • •}

Page

44

67

. .

70

Table 1.

2.

5.

6.

7.

8.

9.

LIST OF TABLES

Animals Resig:hted More Than Ten Times

Monthly Mean Body Weights for Adult Hedgehogs

Monthly Apparent Sex Ratios of all Animals Seen ••

Age Structure of British Hedgehogs From Morris (1968) ••

Monthly Mean Weights for the Male Hedgehog's Reproductive Tract, Testes and Accessory Glands

Combined

. .

Seasonal. Changes ⁱⁿ the Numbers of Pregnancies ••

Home Range Data for Adult Femal.es Home Range Data for Adult Males Home Range Data for Juveniles

{vi)

. .

. .

. . . .

Page

11.

21 •

28.

30.

32.

48.

51 •

54.

Figure

1.

2.

3.

4.

6.

7.

Plate

2.

)&4

LIST OF :ILLUSTRATIONS

Seasonal Activity

. . ..

Regression of Activity on MGT Seasona.1 Changes in Breeding

Parameters

Minimum Convex Polygon Home Ranges of Adu1t Females Minimum Convex Polygons Home

Ranges of' Adu1t Females Minimum Convex Polygon Home

Ranges of Adul. t Males Minimum Convex Polygon Home

Ranges of' Juveniles

. . ..

Centra1 Pi.ne Plantation with the Deep Plantation in the Back.ground Typical Summer Pasture. Deep Pine

Plantation in the Background Typical Nest Sites Within the Pine

Plantations. •• •• •• ••

Lush Grass Surrounding Area of Pig Sty Effluent . A rich food supply :for the Hedgehogs. • • • • • •

(vii)

Page

16 16 33

49 50

52 55

6 6

7

8