bluuebunny/crossref_metadata_2025 huggingface dataset:
L’influence du milieu sur les émissions vocales des oiseaux : L’évolution des chants en forêt équatoriale
Authors: Chapuis C.
Published: November 2022

Une adaptation des chants d’oiseaux au milieu particulier du sous-bois de la forêt équatoriale est suggérée par la simple comparaison globale de la majorité des espèces entendues dans ce type d’habitat avec celles vivant dans des milieux plus ouverts tels que la savane.

Pour mieux préciser les caractères de cette adaptation, nous avons choisi une centaine d’espèces, appartenant sensiblement par moitié à chacun de ces deux milieux, au niveau de chaque famille.

L’analyse spectrale des enregistrements effectués a fourni des données quantitatives sur les deux milieux, et a permis de montrer que la tonalité des chants était plus grave en milieu dense qu’en milieu ouvert. Le phénomène est surtout marqué pour les petites espèces qui ont les chants les plus aigus (abaissement de 1 000 Hz de la fréquence moyenne en milieu dense par rapport au milieu ouvert) et les espèces de taille moyenne qui utilisent le registre moyen (même différence de 1000 Hz).

Par contre les familles à chant grave ont moins évolué, (300 Hz de différence entre les deux milieux). Il semble donc que ce sont les fréquences supérieures à 1 500 Hz qui ont été le plus modifiées, leur transmission étant sans doute altérée en milieu dense. Effectivement, une vérification expérimentale sur la pro¬ pagation des sons, effectuée dans les strates inférieures de la forêt primaire du Gabon, a bien montré que c’est au-dessus de la fréquence de 1 500 Hz que les sons étaient rapidement absorbés par les écrans naturels.

Ce fait nous semble suffisamment remarquable pour être signalé. La longueur d’onde de cette «fréquence charnière» de 1 500 Hz correspond sensiblement aux dimensions des plus grandes feuilles de ce milieu dense, et l’on peut donc penser que ce sont les réflexions multiples sur ces feuilles par ailleurs épaisses qui sont la principale cause d’une telle absorption.

Parallèlement nous constatons que d’une façon générale les spectres acoustiques sont larges en milieu ouvert, étroits en milieu fermé. Il semble donc que l’oiseau ait, dans les limites de son registre disponible, concentré son énergie sur la note fondamentale, donc la plus grave, et augmenté ainsi la portée de son chant.
Recherches écologiques dans la savane de Lamto (Côte-d’Ivoire) : Production annuelle des populations naturelles du lézard Mabuya büttneri (Matschie)
Authors: Barbault R.
Published: November 2022

Monthly counts were made of populations of the skink Mabuya büttneri during a four year period (1964-1968) in burnt savanna areas at Lamto in the Ivory Coast. Densities ranged from 30-60 individuals per hectare, maximal densities being recorded in May at the time of late egg hatching. No individuals were recorded from the time of savanna burning in late January until early March, when hatching started. Popu¬ lations in March were entirely comprised of newly-hatched indi¬ viduals. Fresh weight estimates of annual production varied from 164-328 g/ha, according to year and site.
Recherches écologiques dans la savane de Lamto (Côte-d’Ivoire) : Production annuelle d’un ver de terre Millsonia anomala Omodeo
Authors: Lavelle Patrick
Published: November 2022

Millsonia anomala, espèce d’assez grande taille, constitue la majeure partie du peuplement d’Oligochètes de la zone de bas-fonds où a été réalisée cette étude : l’effectif moyen est de 180 000 individus par hectare représentant une biomasse de 170 kg en poids frais.

La reproduction survient deux fois par an à la fin des périodes pluvieuses. Les générations successives peuvent être reconnues et isolées graphiquement sur les histogrammes construits en portant en abcisses les classes par ordre de poids croissant et en ordonnées les effectifs des classes.
Recherches écologiques dans la savane de Lamto (Côte-d’Ivoire) : Etude quantitative préliminaire des micro-arthropodes du sol
Authors: Athias Françoise
Published: November 2022

A preliminary, quantitative study of soil micro-arthropod populations was made during a four-month period in burnt and unburnt savanna areas at Lamto in the Ivory Coast. Soil samples were taken to a depth of 80 cm using a core borer, and extraction undertaken using a dry funnel method.

Densities were low in soil, higher under grass clumps. Average densities of Acarina, numerically the dominant micro-arthropod group (comprising 74 % of total), were 34,000/m² and 20,000/m² in burnt and unburnt areas respectively. Acarina were more abundant in the 0-5 cm and 40-60 cm soil horizons than in intermediate horizons. Within the Acarina, Actinedida were numerically the most important group, while Oribatida were poorly represented.

After the Acarina, Collembola were the most important soil micro-arthropod group, followed by Myriapoda and Diplura.
Migration et autres types de déplacements de la Mésange noire Parus ater en transit au col de la Golèze . 1e partie
Authors: Scherrer Bruno
Published: November 2022

From 1965 to 1970, 15,525 Coal tits were captured at La Golèze pass, situated in the French Alps at approximately 35 Km south of Lac Leman and 3 Km South-West of Bretolet pass. The number and location of mist-nests remained the same throughout each trapping period (mid-august to mid-october) from one year to another. Fat deposits and coloration of the upper parts of a large number of birds were noted, wing length measured, and the weight, age and sex determined.

1) The number of captures varied considerably from year to year despite constant trapping effort : 5408 in 1967 and 9131 in 1969 (years of irruption) ; 209 in 1966 and 537 in 1968 (years of partial migration) ; 162 in 1965 and 71 in 1970 (years of erratic movement).

2) Coloration varied from year to year. In 1968, a year of partial migration, large individuals had grey-green upper parts. In 1969, a year of irruption, small individuals had grey-blue upper parts. In 1970, a year of erratic movements, the large individuals had grey-green upper parts.

The studies of Jouard (1928) and of Snow (1955) suggest that there are a greater proportion of individuals of northern origin in the autumn of years of irruption than in other autumns. Some of the recaptured birds (fig. 11) and field observations of the present study confirm these conclusions. 3) The locations of recapture of 102 coal tits, ringed at La Golèze and Bretolet during irruption years, indicated a winter range which included Languedoc-Roussillon, northern Italy and Italian peninsula. During years of partial migration and erratic movements, no recaptures were recorded.

4) Coal tits invariably migrated at very low altitudes and by sinuous routes, generally following lines of woody vegetation and avoiding mountain obstacles.

5) The dates of passage of Coal tits varies considerably from year to year. The passage was late in years of partial migration (not before October), and early in years of irruption (the end of August).

6) In 1969, the migration of adults preceeded that of immatures by fifteen days.

7) The percentage of adults was very high (42,5 % in 1969 and 23 % in 1967) during irruptions, very low during partial migrations, and very variable during erratic movements.

8) The male/female sex-ratio approximates to 1/1 during irruptions, 1/4 during partial migrations and 1/1 during erratic movements.

9) The dates of passage for males and females did not differ significantly.

10) During irruptions, the dates of passage of Northern populations coincided with the dates of passage of all other individuals.

11) The migration of the Coal tit takes place exclusively during daylight hours. The passage begins around 06.30 hours (local time), attains a maximum at 11.00 hours and decreases throughout the afternoon.
Densités, biomasses et structures des populations d’Ongulés sauvages au Parc de l'Akagera (Rwanda)
Authors: Monfort Alain
Published: November 2022

Population ecology of wild ungulates has been studied during two consecutive years (September 1968 -August 1970) in the Akagera National Park, Rwanda.

Counts have been made four times a month on six line-transects using a technique similar to that of Lamprey (1963-64).

Each of the 13 more common species has it own ecological preferences, and no inter-specific competition occurs (Table I).

Average densities and standing crop biomasses are given for each of the major habitats of the area (Tables II, III, IV). The densities of sedentary species are remarkably stable from year to year.

Average standing crop biomasses (fresh weight) range from 2705 Kg/Km2 in the Mutara grasslands to 28.286 Kg/Km2 in the tree savanas of the plains. Seasonal fluctuations are due to the seasonal breeding of some species and seasonal migrations of others.

Data are given on the sex-ratio and age-ratio of the major species. Their social structure is described. Habitat is shown to influence social structure in the Topi and the Impala. Both species have different patterns of population dispersion and social grouping in different vegetation types. Among impalas, and apparently also among topis, the percentage of young of the year and juvenile individuals is smaller in areas of high population density.
Biomasse végétale et production primaire nette
Authors: Bille Jean-Claude , Poupon H.
Published: November 2022

The standing crop biomass, both above and below the ground, has been estimated for the 3 major grassland vegetation types which cover about 65 % of the study area defined in the previous paper and for the 3 most common tree species as well. The net primary production of the above-ground herbaceous vegetation has been measured in the same vegetation types, using the method of Wiegert and Evans as modified by Lomnicki et al. (4968). The root biomass estimated at the peak of the growth period ranges from 4.4 to 2.5 tons/ha, and the above-ground biomass from 0.7 to 3.5 tons/ha, depending upon vegetation type.

The standing crop biomass of trees and shrubs averages 3.5 tons/ha.

The net above-ground herbaceous production ranges from 0.8 to 4.2 tons/ha, 2 to 3 % of which is represented by seeds. This production is strongly influenced by rainfall.

Litter production by tress and shrubs averages 87 Kg/ha.

All biomass and production figures are given in dry weight.
Le gîte du Castor du Rhône (Castor fiber). Description et comportement constructeur
Authors: Richard P. B.
Published: November 2022

The Eurasian Beaver (Castor fiber) has different types of shelter in France. The burrow generally comprises a short tunnel which rises from beneath the surface of the water, and leads to an hemispheric dwelling place which is situated a few centimetres underneath the level of the water. The burrow is devoid of all material, apart from a mattress of wood, shreaded by the Beavers. The roof is often pierced by an air hole for ventilation. The burrow may vary in relation to the texture of the bank, the variations of the water level, the time period during which the burrow is used, etc. Therefore one can envisage a several levelled dwelling and a burrow with long tunnels ; others are repaired by a visible mass of logs which gradually resemble the hut.

The hut is not dug inside the bank but is built above the bank. Contrary to former opinion, in France the Beaver constructs huts closely resembling those of the Canadian species ; that is to say, a dome of wood and mud, the structure of which is subject to incessant change depending on the number of animals and outside conditions (i. e. mainly, variations of water level and weather) .

The hut can attain great heights while at the same time concealing many independent dwellings. Its origin can possibly stem from a tunnel in the hank or from the bottom of the pond.

The Winter Store. This consists of a pile of willow and poplar branches immersed in close proximity to each other, which are accessible to the Beavers even in times of frost. This supply of the bark of Salicaceae enables these rodents to survive cold periods.

The Screen stretches from the hut towards the water and hides the to-and-fro movements of the dwellers.

Beavers can adapt themselves to unusual conditions. Thus they can construct huts of reed like those of the muskrat : they can live in caves or in the flooded basements of mills ; or indeed in outside shelters for a part of the year.

Building Behaviour. The neural structures of the Beaver do not differ from those of other Bodents apart from the thickness of its brain cortex. However its building behaviour is unique among mammals. It enables the animal to transform its environment to suit its needs.

The paper describes the different stages of hut building, from tunnels dug in the bank or from the bottom of a pond.
Ecologie de migrateurs tropicaux dans une zone préforestière de Côte-d’Ivoire
Authors: Thiollay Jean-Marc
Published: November 2022

Rollers (Coraciadidae) and Bee eaters (Meropidae) have been studied during three years in a guinean savanna — with galleries and patches of dense forest — in the Ivory Coast. Annual cen- suses of the breeding populations of savanna Rollers have been made by dilferent methods. For the two species a mean density of 1 individual per 4 or 5 hectares has been recorded with a production of young of 22 to 26 %, mainly in May.

Three pairs of related species (Merops gularis and M. albi-collis ; Eurystomus gularis and E. glaucurus ; Coracias cyano-gaster and C. naevius) are compared from an ecological and physiological stand-point. The first-mentioned species of each pair is sedentary, the second migratory. Two of the three sedentary species are forest birds, while all the migrants are savanna birds, with the exception of M. albicollis which also lives in cleared and cultivated forest. Competition is avoided between the two populations through the occupancy of separate ecological niches.

Congeneric species live in dilferent biotopes (or at least vegetation layers). Sedentaries hunt more easily in and around dense vegetation (adaptation to the conditions prevailing during the wet season), while the migrants prefer the most open spaces. The diet of the resident birds is more varied, the migratory species being more specialised in their feeding on swarms of winged ants and termites. Migratory species are much better adapted to the exploitation of this seasonal production or to the appearance of newly accessible prey (ground insects on recently burnt patches of savanna), being able to move rapidly from one place to another and to concentrate locally in large numbers.

Dates of arrivals and departures are compared with the calendar of rains and it is suggested that the timing of the migratory movements in the northern part of the breeding area of these birds is more under the dépendance of the seasons than influenced by local conditions. But it is possible that the rainy season in the Ivory Coast would be too wet to allow a good survival for the populations of these species ; this could also explain the disappearance of our breeding Eurystomus glaucurus from June to September.

Merops albicollis, a typical intra-african migrant, shows a premigratory fattening of about 7 %. This occurs at the end of the prenuptial moult and coincides with the beginning of the increase in the size of the gonads.
La fonction d’apparence chez les Tettigonioidea
Authors: Leroy Yveline
Published: November 2022

Five different morphological types can be distinguished among Tettigonioidea (Orthoptera) : the «standard» type, the «vertical flat», the «horizontal flat», the «elongated» and the «spherical». The last four help to conceal the insect within its environment. These morphological types are defined biometrically.

The resemblance to the surrounding vegetation is enhanced not only by a variety of colours, patterns and microstructures of the integument, but also by special behaviour patterns and coaptations (Cuénot, 1926). This combination of morphological and behavioural features undoubtedly plays an important role in predator-prey relationships. The total physical characteristics of the prey is less important in terms of adaptation than is its manifest appearance.
La régénération de la strate herbacée
Authors: Bille Jean-Claude , Poupon H.
Published: November 2022

La production de diaspores a été calculée sur la zone de référence de Fété Olé en 1970 et 1971 à partir de la structure des trois formations herbacées les plus importantes et des productions unitaires des espèces qui les constituent. Cette production s’établit aux environs de 30,6 kg/ha. Lorsque les graines ont été libérées, elles sont soumises à des déplacements par les agents atmosphériques et éventuellement les animaux, cependant qu’une fraction est consommée (10,3 kg/ha). Des études de germination en précisent les conditions et l’importance : 3,3 kg/ha. En ce qui concerne les graines résiduelles, les mesures démontrent qu’une fraction seulement de la production est détruite chaque année et que des graines reliques des années précédentes (environ 17 kg/ha) se retrouvent au sol à l’issue de la saison de production.
Mammalian socialization and the problem of imprinting
Authors: Allyn Georges
Published: November 2022

The ecology and behaviour of the Oribi Ourebia ourebi have been studied during two consecutive years in the Akagera National Park, Rwanda.

Density estimations have been made regularly along line transects and average values are given for each of the major habitats of the area. Oribis are mostly found on dry savanas in hilly country. They avoid epen plains and more humid valleys. They are not dependent upon permanent water, but are often found near salt licks. Bush fires do not influence their distribution.

Oribis are territorial animals. They are most often met in pairs or family groups. Depending upon population density territories are either scattered or clumped together.

Territorial marking plays an important role in the social behaviour of the species. Scent marking is achieved through the secretion cf interdigital and antorbital glands, as well as through faeces and urine.

The functions of scent marking are discussed. Odours familiar to territorial owners probably give them self-confidence, help maintain the pair-and family-bonds and inform each pair member upon the reproductive status of its partner.

Visual signals mainly have an advertising function.

The sexual display is described. Aggressive postures are seldom seen during the male display, and behaviour sequences which precede copulation are highly ritualized : nose-forward posture, licking of the vulva, nuzzling of the inguinal region, Laufschlag. During mounting, the female adopts a head-low posture. Flehmen was never observed.

Agonistic behaviour can occur between adult males, between adult females, as well as between members of different sexes. As in many other Ungulates advertising display involves proud posture, urination, defecation and scent-marking activities. The threatening animal approaches its antagonist with the head held horizontally and the muzzle pointed towards its rival. Submissive behaviour consists in head-lowering postures. Horn presentation was never observed during fights between males.
Écotopes des arbres et gradients écologiques verticaux en forêt gabonaise
Authors: Oldeman Roelof Arent Albert
Published: November 2022

The ecotope has been defined by Whittaker et al. (1973) as the «full range of adaptations to external factors of both niche and habitat». This term is the only one among those used by animal ecologists which can be applied to plants without extensive redefinition.

An example is then given, based on the analysis of a plot of an evergreen rain-forest in French Guiana. The study of the growth patterns of trees (architectural models), together with that of the forest structure, during successive developmental and successional stages, makes possible a better understanding of the dynamics of tropical sylvigenesis. In an evergreen rain-forest environment, the climate itself does not exert a limiting influence upon forest vegetation. On the contrary, the growth of individual trees, as well as forest succession, are strongly influenced by the micro-climatic feedback effects of developing vegetation. The stratification of a mature rain-forest is both the cause and the result of this biological regulation, which acts through the modulation of the vertical gradients of light and humidity and manifests itself via «inversion levels».

From the beginning of the regeneration cycle (a tree-fall for instance) to its end (a stratified forest with a small net production), numerous transient eco topes can be distinguished. The plant types proposed at the Kandy Symposium (biological nomads, scar species, sedentary species) appear to play the same role in this biologically determined microclimate as Raunkiaer’s biological types in temperate macroclimates : they represent different ways of reacting to the environment by different strategies of energy and nutrient transfer.
La nidification des oiseaux en forêt gabonaise : Architecture, situation des nids et prédation
Authors: Brosset André
Published: November 2022

During a five year period data were collected on the location and the architecture of the nests of 110 species of rain forest birds in North East Gabon. 550 nests were observed, out of which 337 were followed until the departure of the fledglings or the disappearence of the eggs or nestlings.

Many forest species make cryptic nests, some of which are built within bunches of dead leaves (Bleda sp.), others are disguised with dead plant material (Nectarinia sp. ; Malimbus sp.) or with caterpillar’s droppings and silk threads (Sylvietta denti). Warblers of genus Camaroptera conceal their nests between leaves which have been sawn together. The Bearded Greenbul Criniger barbatus incorporates into the rim of its nest the epiphytic fern Microgramma owariensis whose foliage remains green during the incubation of the eggs and the rearing of the young. Nicator chloris makes a loose nest «glued » on its support by rotten twigs ; the mycelium which develops in a few days securely binds the nest and its support.

The location of many nests has apparently been selected in order to keep them from being located on the arboreal or terrestrial paths of predators : small trees isolated in the undergrowth, tips of horizontal twigs projecting above open spaces, tips of hanging lianas, branches overhanging water, intervals between the buttresses of the tree trunks, etc. Contrary to what frequently happens in temperate forests no attempt is generally made to conceal nests under foliage. More than two thirds of the nests discovered by the author were subsequently destroyed by predators or accidents. Whereas the concealment of the nest itself does not appear to be a very effective anti-predator device, the location of the nest is much more efficient : 70 % of nests located in the small trees of the undergrowth were destroyed as against 50 % of those built at the tip of projecting twigs, and 35 % of those overhanging water. Twenty per cent only of the nests located between buttresses were destroyed.

A comparison is made with Maria Koepke’s observations in Eastern Peru. Unrelated species with similar ecological requirements usually have similar nesting habits. Some striking cases of convergence are mentioned between Galbulidae and Meropidae, Alcedinidae and Bucconidae, Tyrannidae and Nectariniidae, Icteridae and Ploceidae.
Exemple de prédation naturelle sur une population nicheuse de Quelea Q. Quelea (L.) au Mali
Authors: Thiollay Jean-Marc
Published: November 2022

The predation pressure upon nine breeding colonies of Red-billed Quelea (Quelea q. quelea) has been estimated in September 1973 in Eastern Mali, Western Africa.

Large numbers of predatory birds (Kites, Hawks, Ruzzards, Eagles, Falcons, Storks, Herons, Ibises, Hornbills, Crows, etc.) were found to feed upon young queleas : up to 763 predators in a colony of 28,000 nests. Details are given on feeding techniques, food preferences and average daily consumption of the most important predators.

In this particular case, 32 % of the nests were destroyed between laying and hatching times. Furthermore 25 % of the nestlings appear to have been subsequently destroyed by predators. On the whole, each adult breeding pair did not produce more than 1,7 fledglings. The causes of this unusually high mortality rate are discussed.
Ecologie de Cercopithecus ascanius schmidti dans les environs de Bangui
Authors: Galat-Luong Anh
Published: November 2022

Preliminary observations on the social structure and ecology of a troop of Red-tail monkeys (Cercopithecus ascanius schmidti) were made between 1970 and 1972 around Bangui, Central African Republic.

The age-graded male troop studied ranged from 17 to 23 troop members, including 4 adult males, one of which (the GM male) was much bigger than the others, one subadult male (PN), six adult females, six juveniles and six infants. The troop very often splits into sub-groups by day as well as by night : «family parties » (Haddow, 1952) made up of one adult male and one adult female accompanied by its young of the year, female travelling parties, juvenile play groups. The association between the «master male » GM and the subadult male PN lasted for a whole year ; both of them were usually found staying outside the rest of the troop.

The troop’s home range averaged 15 hectares, five of which representing the core area. Two different sleeping trees were used during the observation period. Some details are given on the diet, the daily schedule of activity, and their seasonal variations.

Mating occured during the day and outside the group. Seasonality of breeding is the rule ; six young infants were observed in September.
Coexistence de Vipera aspis et de Vipera berus en Loire-Atlantique : un problème de compétition interspécifique
Authors: Saint Girons H.
Published: November 2022

L’étude en Loire-Atlantique de la zone de contact entre Vipera aspis et V. berus montre clairement que les deux espèces s’excluent mutuellement. Non seulement la zone de coexistence est très étroite (1 à 2 kilomètres), mais en réalité même cette bande est constituée par des petites populations juxtaposées et non mélangées. Bien que possible, l’hybridation demeure un phénomène exceptionnel et, en pratique, les deux espèces sont sexuellement isolées.

En l’absence d’intolérance active, nous avons cherché à connaître la nature de cette compétition interspécifique, en étudiant l’écologie et le cycle annuel des deux espèces dans les mêmes localités et les mêmes biotopes. Bon nombre de différences ont été mises en évidence, les unes d’ordre spécifique (le cycle sper-matogénétique, la nature des proies acceptées, etc.), d’autres représentant la simple conséquence des conditions climatiques locales (par exemple, la reproduction triennale de Vipera aspis).

Dans la région étudiée, à étés frais, V. aspis souffre d’un net déficit thermique : les femelles ne se reproduisent plus que tous les trois ans en moyenne et la date de la parturition se rapproche dangereusement du début de l’hivernage. Ceci est certainement dû à une thermorégulation écologique moins efficace, peut-être aussi à des exigences thermiques supérieures lors de la digestion et de la gestation.

Vipera berus est très certainement avantagée par un taux de natalité plus élevé et par un régime plus éclectique. Mais, gardant un comportement adapté à la vie dans des régions beaucoup plus froides, elle s’expose davantage à l’action des divers prédateurs. Ce phénomène est aggravé par le cycle spermatogénétique comportant une spermiogenèse vernale qui oblige les mâles à une recherche intense et dangereuse de l’insolation à cette époque.

Le fait que les deux espèces ne puissent cohabiter et s’éliminent mutuellement, bien que leurs exigences écologiques diffèrent par un certain nombre de points, est dû apparemment à ce qu’elles fréquentent les mêmes biotopes et se trouvent ainsi soumises ensemble à une pression de prédation à laquelle elles réagissent différemment. Un léger désavantage suffit alors pour que l’une d’elles se trouve éliminée, sans qu’intervienne de compétition, alimentaire ou autre.

D’après l’ensemble de nos observations, la frontière entre Vipera aspis et V. berus se situe au point où la baisse de fécondité de V. aspis n’est plus compensée par la plus grande vulnérabilité de V. berus aux prédateurs, et inversement.
La colonisation de la mangrove par Cercopithecus aethiops sabaeus au Sénégal
Authors: Galat Gérard , Galat-Luong Anh
Published: November 2022

Cercopithecus aethiops sabaeus have been known since 1906 to inhabit the mangroves of Southern Senegal, where they are called locally «mangrove monkeys».

An age-graded male troop of 33 individuals has been briefly studied in 1975 around the estuary of the Saloum river ; usually it split into smaller sub-groups or foraging parties during the day and even sometimes during the night. The troop’s home range averaged 138 ha. Territorial contests between adult males of adjacent troops have been observed ; these involved «loud barks», «chest exposure» and «penile display».

The troop studied spent 80 % of its time within the mangrove and only 13 % on the mainland. Sleeping trees can be located in both habitats, but mostly in the mangrove. Though C. a. sabaeus can swim, they prefer to cross mud flats and shallow water channels at low tide, or progress through the Rhizophora stilt-roots or pass from one tree crown to the other.

The time-budget of the troop is given. The monkeys were observed feeding during 8.1 % of their activity time only. In 52 % of the cases they were seen hunting fiddler crabs (Uca tangeri) and 22 % of the cases eating Rhizophora flowers, fruits, shoots and young leaves, as well as the «pith» of young stilt-roots. Two different hunting techniques for crabs are described.
Structure et dynamique d’un peuplement d’Amphibiens en savane protégée du feu (Lamto, Côte-d’Ivoire)
Authors: Barbault R.
Published: November 2022

The bush-fires which occur yearly in the Lamto savana, during the dry season, do not affect Amphibian populations directly, but rather through their action upon vegetation structure and micro-climate.

The population density and relative abundance of the various species were studied during 1964-1965 in two unburnt 30 X 30 m plots : one which had been protected from fire for two years and another which had remained unburned for five years. Comparisons were made with populations from burned plots and nearby gallery forests.

The obvious differences of population densities and relative species abundance so far described between savanna and forest communities, as well as between «bottom» and «plateau» communities within the savanna, tend to disappear when bush-fires are prevented. However the seasonal cycle of population abundance remains basically the same in both cases.

In unburnt savanna plots the density of Amphibian populations increases rapidly and is already noticeable during the second year. Population density may be increased 2 to 3 fold. This is mostly due to a proliferation of one species (Arthroleptis poecilo-notus), which takes place simultaneously with the reduction in numbers of the toad Bufo regularis.
Dry season nesting of the Golden sparrow near Richard Toll, Sénégal
Authors: Bruggers Richard L. , Bortoli Louis
Published: November 2022

A small, dry season Passer luteus nesting colony was studied near Richard-Toll, Senegal in April and May 1975. Differences between this colony and wet season colonies included a) smaller nests of somewhat different material ; b) lower nesting success ; and c) the presence of weed seeds in the diet of nestlings.
Le genre Vaucheria dans l’étang du Vaccarès et une sansouire submergée voisine
Authors: Vaquer André
Published: November 2022

Quatre espèces du genre Vaucheria ont été récoltées et décrites pour deux stations en Camargue. Elles témoignent du caractère halomorphe de ces deux stations.
La territorialité chez la Rousserolle verderolle Acrocephalus palustris
Authors: Dowsett-Lemaire Françoise
Published: November 2022

Le comportement territorial de la Rousserolle verderolle Acrocephalus palustris a été étudié dans une population marquée de quelques dizaines de couples nichant dans la vallée liégeoise (Belgique) .

Liées à l’exploitation d’une végétation herbacée dense, les Verderolles occupent des territoires groupés de petites dimensions (quelques ares en moyenne) qui contiennent des sites potentiels de nid (lig. 1 et 4). Le couple se forme lorsqu’une femelle s’arrête pour sélectionner un site de nid. La plupart des couples continuent à défendre un territoire jusqu’à la naissance des jeunes, c’est-à-dire jusqu’à une époque où les tentatives d’installation de nouveaux venus sont presque terminées. Les couples tardifs cessent de défendre un territoire relativement plus tôt dans le cycle. L’essentiel de la nourriture pour les jeunes est recherché en dehors du territoire initial (fig. 1 C) ; dès avant ce stade, les excursions extraterritoriales sont fréquentes, surtout chez les mâles.

Outre leurs congénères, la Rousserolle effarvatte A. scirpaceus est la seule espèce locale que les Verderolles expulsent systématiquement de leur territoire.

Le rôle principal de défense du territoire revient aux mâles (dont le chant plein a une fonction territoriale), mais les femelles prennent une certaine part dans la défense du canton surtout en cas d’absence (temporaire ou non) de leur partenaire.

La dimension du territoire occupé à un moment donné dépend de l’époque de l’installation, de la position du territoire par rapport aux cantons voisins, du tempérament des oiseaux, du type de végétation contenu dans le territoire, et du stade du cycle. Les territoires des mâles cantonnés en début de saison (mi-mai) sont plus grands que ceux des individus arrivant au milieu ou vers la lin de la période principale des installations (fin mai). En moyenne, le territoire s’étend nettement lors de la formation du couple, puis sa surface décroît jusqu’à la fin de l’incubation (fig. 5). La dimension moyenne du territoire est inversement proportionnelle à la densité locale des sites de nid. Au cours de la saison exceptionnellement sèche de 1976, les sites de nid étaient plus dispersés et la densité des couples (10,6 couples/ha) a été la plus basse observée en quatre ans.

La possession par le mâle d’un territoire riche en sites de nid est sans doute indispensable à la réussite de la formation du couple. Pendant les parades nuptiales, le territoire protège le couple contre les interférences des mâles voisins. Enfin, plusieurs faits d’observation suggèrent que la territorialité contribue à limiter la densité de la population nicheuse.
Le cycle saisonnier des lipides de réserve chez deux espèces de rongeurs du Sénégal
Authors: Hubert B. , Demarne Yves
Published: November 2022

The seasonal cycle of lipid deposition has been studied for two consecutive years in populations of Mastomys erythroleucus and Taterillus gracilis from a sahelo-sudanian woodland in Senegal.

At the beginning of the dry season young Mastomys, 2 to 3 months old, feed mostly upon the temporarily superabundant seeds and store fat. These fat deposits, largely made of oleic acid, are used during the long dry season, when food is scarce. During the rains, Mastomys diet changes, as does the nature of their lipid stores which then contain a larger percentage of linoleic acid. This last fatty acid is quite likely provided to the animals by Cucumis melo seeds, which are frequently consumed by Mastomys at this time of the year, when breeding takes place.

The seasonal cycle of fat deposition in Taterillus gracilis is similar to that of Mastomys erythroleucus, but less marked. The diet of this gerbilid is also more varied, and its breeding season spread over a longer time interval.

The above observations were made at the end of the 1975-1977 rodent outbreak in Northern Senegal. However, fat deposits remained very substantial in January 1976, at the time when population densities reached their peak values. Similarly, the rodents still maintained sizable fat deposits during the “crash” period, from August 1976 to the end of 1977. In the present situation, at least, population fluctuations were clearly not dependent upon the nutritional status of the rodents studied.
Les conséquences d’un supplément alimentaire sur la dynamique des populations de rongeurs au Sénégal. II. Le cas de Taterillus pygargus en zone sahélienne
Authors: Poulet A. , Couturier Guy , Hubert B. , Adam François
Published: November 2022

Un aliment artificiel à base de céréales fut distribué pendant les neuf mois de la saison sèche 1976-1977 sur 2,25 ha d’une savane sahélienne du Nord-Sénégal, qui supporte une population du Gerbillidé Taterillus pygargus.

Les résultats d’une série de piégeages avec marquages et recaptures multiples sur la surface approvisionnée et sur une surface témoin montrent que les conséquences du supplément nutritionnel furent d’une part une prolongation de la saison de reproduction, d’autre part une concentration d’individus pendant la première partie de la saison sèche, de novembre à janvier ; mais, le très fort déclin qui affecta la population de Taterillus dès le mois de décembre 1976 ne fut pas modifié par la présence du supplément alimentaire : l’origine de la mortalité ne pouvait donc être une raréfaction de la nourriture disponible.
Caractéristiques du régime alimentaire de la Chouette effraie (Tyto alba) dans une région naturelle du Centre de la France : la Grande Sologne
Authors: Henry Claude
Published: November 2022

The diet of the Barn Owl (Tyto alba) in Grande Sologne, Central France, is described. Pellet samples were collected from 35 localities. They included more than 18,000 food items. The collecting areas were uniformly distributed throughout the region, one sample being collected from each of the 35 grids of the 1/25,000 scale map. The number and relative importance of the mammal species (Table I) captured by barn owls show little variability within the individual study areas. However, three different dietary patterns (called facies) were distinguished within the area studied, on the basis of the frequency of the various prey items. In each of the three facies however, the diet composition remained the same. Prey abundance can be adapted to a Motomura model. This is interpreted as the consequence of the adaptation of the predator to the overall distribution of the more abundant prey species. Important fluctuations in the individual number of prey can nevertheless occur
Le peuplement herpétologique d’un massif du Haut-Languedoc. II. Influence de quelques facteurs sur la répartition des reptiles
Authors: Livet F.
Published: November 2022

The plant community structure and the influence of some climatic factors on the distribution and population density of the reptiles of the Caroux-Espinouze mountain range (Southern France) are discussed. Fixed transects counts were used to estimate species distribution and abundance.

The activity of the Mediterranean species is influenced more by wind speed and temperature than that of more northern species, e.g. Vipera aspis.

The climate of the area, which is intermediate between the Mediterranean and the Atlantic climates, exerts a strong influence on the population density of the reptile species in question. The structure of the reptile community may vary from year to year depending upon short term climatic fluctuations.

The structure of the plant communities also influences the structure of the reptilian communities, and the population density of the species concerned. Heathland communities with a closed canopy growing on a deep soil harbour the denser and more diverse reptile communities of the area. This may be correlated with the availability of numerous shelters, including rodent burrows, and of many prey species ; behavioural thermoregulation may also be facilitated. Species diversity and population density decrease in more open heathland communities, meadows and forests.

Three groups of species can be distinguished on the basis of their range of habitats : (1) those with a wide range : Elaphe longissima, Lacerta viridis, Malpodon monspessulanus, Natrix maura ; (2) those with a moderate range of habitats : Vipera aspis, Elaphe scalaris, Anguis fragilis, Coluber viridiflavus, Natrix natrix, Lacerta muralis ; and (3) those with a narrow range of habitats : Psammodromus algirus, Lacerta lepida and L. vivipara.
Les particularités démographiques et socioécologiques du Coliou strié dans le Nord-Est du Gabon. II. Stratégies adaptatives de l’espèce
Authors: Decoux Jean-Paul
Published: November 2022

The observations carried out from 1973 to 1977 on a population of speckled mousebirds (Colius striatus) at Makokou, Gabon, have been summarized in a previous paper (Rev. Ecol., Terre Vie, 36, 1982 : 37-78). An attempt is made here to integrate the available data into a meaningful whole, in order to demonstrate the adaptiveness of the tactics adopted by this amazing bird.

None of the remarkable behavioural traits and ecological characteristics of the Speckled mousebird would be understandable without consideration of its unusual physiology and nutrition. A low metabolic rate and a vegetarian diet allow this bird a good deal of «free time» to develop play activities, even among subadults and adults.

Extensive social cooperation between members of the same population is the most striking feature of the breeding biology of Colius striatus ; this cooperation enables the species to maximize its breeding potential.

Among sedentary breeders, the long-lasting pair-bond and the frequent presence of subadult and adult «helpers at the nest» probably contribute to increase the expectation of life of fledged individuals. The existence of a «reserve of potential breeders», made of young bachelor males and satellite adult females, also allows the speckled mousebirds to adapt quickly their demographic strategy to rapidly changing environmental conditions. They cannot therefore be easily classified either among r or K-strategists.

Nomadic groups also enable the species to colonize unstable habitats, such as clearings around human settlements, or gaps in the mature rain-forests. On the whole Colius striatus is a highly adaptable bird, behavioural flexibility being the rule at the individual as well as at the population level. Occasional cases of communal nesting and even polyandry are extreme examples of this flexibility of behaviour.
Production et consommation de graines en milieu Sahélo-Soudanien au Sénégal : bilan général
Authors: Gillon Dominique , Adam François , Hubert B. , Kahlem G.
Published: November 2022

La production annuelle de graines par la végétation herbacée et leur consommation par les oiseaux, les rongeurs et les fourmis Messor galla ont été étudiées au cours de 3 années successives. La production annuelle de graines a varié de 286 kg/ha à 1 061 kg/ha, les oiseaux en auraient consommé 6 % à 26 %, les rongeurs 1 % à 15 % et les fourmis 0,4 % à 2 % selon les années. Au total, 1/3 à 2/3 des graines produites auraient été consommées si on tient compte de l’impact des insectes endophytophages qui se développent dans les graines de l’espèce dominante Cassia tora (Leguminosae).

Globalement, pendant la période d’étude, les quantités de graines n’ont pas semblé un facteur limitant pour les populations granivores et, réciproquement, l’impact des granivores n’a pas paru compromettre le renouvellement de la strate herbacée l’année suivante. Cependant, les différents groupes granivores effectuant des choix parmi les graines disponibles, il est probable qu’il y a compétition pour certaines graines particulièrement recherchées et que leur impact influe sur l’équilibre entre les espèces herbacées.

Ces 3 groupes granivores, systématiquement éloignés (oiseaux, rongeurs, fourmis), utilisent certes la même source de nourriture, limitée en quantité et variable dans le temps, mais ils diffèrent quant à leur mode d’utilisation spaciale et temporelle de cette même ressource.
Habitat et comportement du poisson amphibie Periophtlamus koelreuteri africanus Eggert à Tuléar. Comparaison avec le P. sobrinus Eggert sympatrique
Authors: Brillet Charles
Published: November 2022

La présente note apporte des informations sur l’écologie et le comportement du Poisson amphibie Periophtalmus koelreuteri africanus Eggert et compare ces données à celles recueillies sur un autre Périophtalme sympatrique, P. sobrinus Eggert.

Ces deux espèces, de tailles différentes, qui partagent les mêmes banquettes de vase en certains points des mangroves, se distinguent l’une de l’autre par plusieurs traits éthologiques.

Bien qu’on puisse les rencontrer toutes deux en mangrove (où la densité de population de P. Sobrinus est infiniment supérieure), P. koelreuteri s’adapte aussi à un substrat plus rocheux, ce dont sobrinus est incapable.

Les deux espèces creusent un terrier, mais la structure de cet abri est différente : une seule galerie d’accès surmontée d’un unique rempart de vase pour koelreuteri, deux remparts et deux galeries chez sobrinus.

Dans le domaine de l’utilisation de l’espace et des relations entre individus, il apparaît que P. koelreuteri africanus fréquente un domaine très vaste aux alentours de son terrier. Peu agressif, il ne semble pas défendre un véritable territoire avec la détermination dont fait toujours preuve P. sobrinus.
Le rôle de la végétation dans l’emplacement des sites de reproduction chez Circus cyaneus L. et Circus pygargus L. dans des secteurs de reboisement en conifères
Authors: Cormier J.P.
Published: November 2022

The location of Hen and Montagu’s Harriers nests was studied from 1970 to 1982 in a conifer plantation and in surrounding moors of heath and thorn-broom in Maine-et-Loire, near Saumur, France. The Hen Harrier prefers to nest in conifers and uses places where trees are 4 to 27 years old. Montagu’s is more frequent on moors and nests in younger pine plantations. The decrease of the Montagu’s Harrier population from 22 pairs in 1972 to 8 in 1982 cannot be explained entirely by the increase in height of the Pine trees. Other factors might interfere, particularly competition between the two species as far as the nesting area is concerned.
Allocation de ressources et effort de reproduction : le cas des lézards
Authors: Pilorge Thierry , Barbault R.
Published: November 2022

The concept of reproductive effort and the problems associated with its measurement in lizards are reviewed and discussed. Many authors use indices such as the Relative Clutch Mass (R.C.M.) which are of limited value.

Though not yet in common use, the energy budget approach looks promising, especially since field radioisotope techniques are now available.

The role of the energy stored in fat deposits, and of that invested in tail regeneration, is discussed. Both seem able to influence reproductive patterns in lizards.

The demographic component of the reproductive effort (i.e. whether the energy is allocated to a few or many offspring), and the relationships between reproductive strategies and environmental and genetic factors, are also considered.
Structures de population et tables de survie des buffles, topis et cobs de Buffon au Parc National des Virunga, Zaïre
Authors: Mertens H.
Published: November 2022

Les structures de population et les tables de survie de trois espèces d’ongulés sauvages ont été établies à partir de recensements terrestres et par l’étude des échantillons de crânes recueillis tout au long d’une année dans la plaine sud du Parc des Virunga au Zaïre.

Les résultats sont commentés et comparés à ceux d’autres études effectuées dans l’Est Africain.

Quelques caractéristiques du comportement social pouvant expliquer certaines constatations sont également communiquées.