ABSTRACT
A bio-ecological and abundance study of Sakalava Rail
Amaurornis olivieri, an endangered and endemic waterbird of
Madagascar, was conducted from July to October 2015 in the Mandrozo Protected
Area, in the western part of Madagascar. Listening point and play-back methods
were used to census individuals of Sakalava Rail in Mandrozo Lake and its
surroundings. Nests were discovered from tracking the individuals of the pair,
and using a questionnaire with the fisherman. Located active nests were
directly and continuously observed, every day from 6:00 a.m to 6:00 p.m, in
order to track all activities during the breeding period (from nest building to
the full independence of Juveniles). The diet has been studied using direct
observation and taking pictures of the consumed foods. At the site of survey,
16 individuals of this species were counted on a surface of 23,55 ha, which was
used to estimate the population density to 0,68 individual/ha. Three pairs
belonging to three different nests were directly and continuously observed.
Nest construction was assured by both adults and it took three days' on average
to complete a nest (n = 2 nests). Male did more work than female during nest
construction. Nests were constructed in a dense mat of reeds Phragmites
mauritianus and located 56,67 cm (n = 3 nests) on average above water
level. Thirteen matings were observed and lasted 4,08 #177; 0,07 seconds on
average (n = 2 pairs). Clutch size was three eggs in each active nest (nest 1
and nest 3). Incubation started on laying of the first egg and both sexes
incubated. Eggs hatched after 17 days (n = 1 nest). During the 204 hours of the
nest observation, female incubated 51,5 % (105 hours), male 43,1 % (88 hours)
and the nest was unattended for 5,4 % (11 hours). Both male and female brooded
and fed the young. Young remained three days in the nest and they were
completely independent of their parents at 45 days of age. Based on 194
identified food items, Sakalava Rail ate invertebrates: Spiders (53,1 %),
Insects (32 %), Crustaceans (10,8 %) and Mollusks (4,1 %). The habitat of this
species is characterized by the dominance of Reeds in which it nests and feeds.
The home ranges of two radio-tracked individuals were respectively 0,95 and
1,98 hectares. Sakalava rail was aggressive during reproduction season.
Keywords: Bio-ecology, Sakalava rail
Amaurornis olivieri, Waterbird, Endemic, Protected Area of Madrozo,
Madagascar.
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SOMMAIRE
INTRODUCTION 1
I. ZONE D'ETUDE 3
I.1. CHOIX ET IMPORTANCE DE LA ZONED'ETUDE 3
I.2. LOCALISATION DE LA ZONE D'ETUDE 3
I.3. CLIMAT 4
I.3.1. La température 5
I.3.2. La précipitation 5
I.4. MILIEU NATUREL 6
I.4.1. Ecosystèmes 6
I.4.2. Flore et végétation 6
I.4.3. Faune 7
II. MATERIELS ET METHODES 10
II.1. MATERIEL BIOLOGIQUE: ESPECE ETUDIEE 10
II.1.1. Systématique 10
II.1.2. Description morphologique 10
II.1.3. Aire de répartition 11
II.1.4. Mode de vie de l'espèce 12
II.2. MATERIELS UTILISES SUR LE TERRAIN 12
II.3. METHODES DE COLLECTES DES DONNEES 13
II.3.1. Période d'étude sur le terrain 13
II.3.2. Méthodes de recensement 13
II.3.3. Recherche des nids 14
II.3.4. Observation du nid 15
II.3.5. Capture-recapture 15
II.3.6. Mensuration des individus 16
II.3.7. Etude biologique de l'espèce 16
a) Formation du couple 17
b) Construction du nid 17
c) Accouplement 17
d) Ponte 17
e) Mensuration des oeufs 18
f) Incubation des oeufs 18
g) Eclosion des poussins 18
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h) Elevage des poussins 19
II.3.8. Etude écologique de l'espèce 19
a) Analyse de l'habitat 19
b) Détermination du régime alimentaire 22
c) Estimation du domaine vital par radiopistage 22
II.4. TRAITEMENT DE DONNEES 24
II.4.1. Estimation de l'abondance 24
II.4.2. Analyse statistique 24
III. RESULTATS 27
III.1. ABONDANCE ET DISTRIBUTION LOCALE 27
III.2. EFFECTIFS DES INDIVIDUS CAPTURES 28
III.3. MORPHOLOGIE ET MORPHOMETRIE DE L'ESPECE 29
III.3.1. Morphologie 29
III.3.2. Morphométrie 31
III.4. BIOLOGIE DE LA REPRODUCTION 33
III.4.1. Formation du couple 34
III.4.2. Construction du nid 35
III.4.3. Accouplement 37
III.4.4. Ponte 37
III.4.5. Incubation 39
III.4.6. Eclosion 40
III.4.7. Elevage des poussins 40
III.5. ECOLOGIE 42
III.5.1. Habitat 42
a) Emplacement et caractéristiques des nids 42
b) Caractéristiques de l'habitat de nidification 43
c) Perturbations et menaces 45
III.5.2. Domaine vital 47
III.5.3. Régime alimentaire 48
III.6. ETHOLOGIE 51
III.6.1. Types de cris 51
III.6.2. Comportement pendant la période de reproduction
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III.6.3. Agressivité 55
IV. DISCUSSIONS 56
IV.1. ABONDANCE ET DISTRIBUTION DES INDIVIDUS 56
IV.2.
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CAPTURE DES INDIVIDUS 56
IV.3. MORPHOLOGIE ET MORPHOMETRIE DE L'ESPECE 57
IV.4. BIOLOGIE DE LA REPRODUCTION 58
IV.4.1. Formation du couple 58
IV.4.2. Construction du nid 59
IV.4.3. Accouplement 60
IV.4.4. Ponte 60
IV.4.5. Incubation 61
IV.4.6. Elevage des poussins 62
IV.5. ECOLOGIE 63
IV.5.1. Emplacement et caractéristiques des nids 63
IV.5.2. Habitat de nidification 64
IV.5.3. Régime alimentaire 64
IV.6. ETHOLOGIE 65
IV.6.1. Agressivité 65
CONCLUSION 66
REFERENCES BIBLIOGRAPHIQUES 68
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