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IN NEW ZEALAND : WITH SPECIAL REFERENCE TO BREEDING BEHAVIOUR.
A thesis presented in partial
fulfilment of the requirements for the degree of Master of Science in Zoology at
Massey University
BRIAN F.McCONKEY 1971
THE PIED STILT
(HIMANTOPUS LEUCOCEPHALUS,Gould,1837)
CONTENTS
CHAPTER PAGE
I INTRODUCTION 1
A. Introduction 1
i) Aims of the Study 1
ii) Previous Work 2
iii) Affinities 3
B. Habitat Description 3
c.
Climatic Conditions 9i) Rainfall 9
ii) Temperature 9
iii) Wind 11
D. Methods 12
i) Observation 12
ii) Measurements 13
iii) Trapping and Banding 14 iv) Automatic recording 19
II GENERAL BIOLOGY 21
A. Bodily Characters 2'1
i) Measurements of Adult birds 2'1 ii) Seasonal Changes in Body 27
Weights
iii) Seas·onal Changes in Gonad 29 Weights
iv) Plumage and Plumage Cycles 33
v) Status 38
B. Food Analysis. 42
c.
Parasites 45ii.
CHAPTER PAGE
III NON-BREEDING BEHAVIOUR 48
A. Dispersion 48
B. Maintenance Behaviour
52
i) Feeding
52
ii) Bathing
54
iii) Preening
55
iv) Sleeping
57
v) Pseudo-sleeping
58
c.
Aggressive Behaviour59
i) General
59
ii) Intra.specific Reactions
60
(a) Hunch Pursuit
60
(b) Aggressive Upright
62
(c) Parachuting
63
_,iii) Interspecific Reactions
65
IV BREEDING BEHAVIOUR
67
A. Pair Formation
67
B. Territorial Behaviour
68
i) Size of Territory
68
ii) Aggressive Upright
70
iii) Parachuting
70
iv) Choking
71
v) Grass-pulling and Sideways-
73
throwing
c.
Copulation75
D. Nest Building
83
i) Nest site
83
ii) Nest materials:
87
iii) Nest raising 87
CHAPTER PAGE iv) Behavioural Elements 89
(a) Nest-showing 89 (b) Sideways-throwing 93 (c) Sideways-building 93
(d) Scraping 94-
(e) Settling 96
E. Defence of Nest or Young 97 i) Reactions to speci es 97
other than man.
(a) Swooping 97
(b) Chasing 98
ii) Reactions to Man 99 (a) Aggressive flight 99 (b) Furtive Run 100 (c) Butterfly-flight 100 (d) Lure di splay 102-
(e) False brooding 105
v
INCUBATION 109A. Egg laying 109
i) Dates of Laying 109 ii) Time of Laying 110
iii) Clutch size 113
iv) Egg measurements 117
v) Relaying 119
B. Length of Incubation 121
c.
Attentiveness 125i) Mechanical Records 125
ii) Nest Relief 132
D. Temperature of Incubation 138
CHAPTER
.VI BREEDING SUCCESS AND CHICK BEHAVIOUR A. Egg Losses
B. Chick Losses
c .
Influence of Laying Breeding Success. D. Chick Behaviouri ) Anti-predator ii) Aggressiveness iii) Feeding
SUMMARY
ACKNOWLEDGEMENTS APPENDICES
REFERENCES
Date on
PAGE 141 141 146 147
149 149 151 151
152 155 157-'158 '161-169
iv.
TABLE 1.1 1.2
2.1 2.2
2.3
2.4
2.6 4.1
5.1 5.2
5.3
LIST OF TABLES
Major plant species found on Colony I.
Mean monthly measurements of Climatic factors over the Breeding Season.
Measurements of Adults.
Seasonal Bodyweight of Adults.
Seasonal Gonadweights.
Percentage Distribution of Adult Neck and Mantle Plumage Colouration.
Comparison of Adult Measurements with those of Oliver (1955) for Black and Pied Stilts.
Monthly and Yearly Percentage of Birds taking each species as prey.
Nesting habitat of the Pied Stilt.
Distribution of Clutch Size.
Size of smallest and largest eggs and position in the clutch.
Incubation and Body Temperature of the Stilt compared with Penguin and Skua.
PAGE 7
20 22 28 30
34
41
43
85
114 118 120 6.1 Fate of Eggs lost from Hatching Clutches.141 6.2
6.3 6.4
Fate of Eggs lost from All Nests.
Hatching Success on Each Colony.
Fate of Eggs in Each Colony.
142 143 144
FIGURE
1.1 1.2
1.4 2.1 2.2
2.3
2.4
3.3
4.1
4.2
5. 4
5. 5
LIST OF FIGURES
Map of Ar ea of Colony I.
Total weekly rainfall and mean wind force from beginning of layi ng. Mean weekly temperatures throughout laying period.
Clap trap plan.
Length of Wing at First Pri mary. Length of Tarsus.
Relation between Wing Length and Tarsal Length.
Seasonal Variation in Body Weight.
Seasonal Variation in Gonad Weight. Arbitrary areas used in Analysing Stil t Dispersion.
Fluctuation in Stilt Population in New Zeal and.
Fluctuation of Stilt Numbers i n Each Area.
Number of Copul ations per hour of observation in relation to number of eggs l aid.
Occurrence of Copulation i n Relation to Time of Day.
Mean Number of Nest Showing bouts in r el ation t o Number of New Tests. Spread of l aying.
Number of Eggs Laid.
Records of spel ls of Incubation for typi cal day and night periods.
Mean length of sessions per day
throughout t he incubation period for t hree nests.
Percentage time on the nest per day throughout the incubation period for three nests.
PAGE 4
10
15
23
24
25
26
31
49
50 5176
78 90
111 112 126
128
130
vi.
FIGURE PAGE 5.6 Patterns of Egg Arrangement within 136
the Nest.
5. 7
Two periods of temperature recording 139 12 hours apart.6.1 Percentage of those eggs l ai d each 148 week which hatched successfully.
PLATE
Frontispiece 1
2
3
4
5
6
7
8
9
10 11 12 13
14
15
16
17
18
19
20 21 22 23 24
LIST OF PLATES
The Pied Stilt.
Area of Colony I .
Mounds of Coarse Grass and Weeds.
Clap trap in set position. Tambour chart recorder. Radio Receiver for
Temperature Impulses.
Temperature chart recorder. Pair of stilts showing Individual Markings. Preening stilt.
Sleeping stilts.
Hunch pursuit posture.
Aggressive Upright posture. Parachuting display.
Anxious or Alert Upright posture.
Neighbouring pairs choking. One of each pair choking. Female assumes Invitation posture.
Male flicking and dipping beak.
Male mounts and copulates. Walking with Crossed Beaks.
Nest on Built up Mound of Mud. Nest on River Shingle Bed. Nest on Swamp.
Built up Nest on Swamp.
Male and Female Nest showing.
PAGE
6 6 16 16 18 18 36
56 56
61 61 64.
64
72 72 80
80
82 82
86 86 88 88 92
viii
PLATE
25
26 27
28 29,
30
3'1 32
33 34 35 36
Sideways Building.
Scraping in Nest Cup.
Furtive Run posture.
Butterfly Flight.
Lure Distraction.
(a) Running from predator.
(b) Facing predator.
(c) Lying down.
(d) Springing in the air.
Conflict Behaviour.
(a) Standing in Conflict.
(b) Sitting down in Conflict.
False Brooding amongst Rocks.
False Brooding in Shallow Water.
Stilt Settling on Eggs.
PAGE
- .- - 92
95 '10'1 '10'1'103 '103 '104 '104
'106 '106 '107 '107 '134 Stilt be~inning Sideways Building. '134 Stilt turning Eggs. '137 Chick showing Cryptic Colouration. '150
