bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technique et fiabilité des dénombrements aériens de canards et de foulques hivernant en Camargue
Authors: Dervieux Alain , Lebreton Jean-dominique , Tamisier Alain 
Published: November 2022

The changes in abundance of the ducks and coots wintering in the Camargue have been estimated by monthly air counts since 1964. A series of control trials (n = 63) was conducted in 1976 and 1977 to estimate the reliability of the air counts and to calculate the relationship between the numbers estimated from the air by an observer (E) and the actual numbers of individuals counted on color slides (R) of the same bird flocks. The degree of relationship between the two figures is expressed by a correction coefficient (R/E) expressing the accuracy of the measurement, and by a margin of error based upon a statistical model, which indicates the reliability of the measurement. The proposed model is based upon the numerous data available for coots, and it has been extended to populations of diving-and surface-feeding ducks. This model makes the best possible use of the various estimates made during a same census ; it also integrates the spatial distribution of the birds and their numbers.
For coots, the R/E ratio is 1.42 from September to February, and 1.13 in March. Working models derived from the statistical one had to be used for ducks. For diving ducks the correction coefficient is 1.11 early and late in season when ducks are few and scattered ; it reaches 1.28 from November to February when they live in large flocks. For surface-feeding ducks, the R/E ratio is 1.18 early and late in season, and 1.34 from November to January. In all cases the margin of error is about 20 %.
Comment les peuplements de plantes et d’insectes phytophages se façonnent mutuellement : la théorie coévolutive de la structure des peuplements
Authors: Lachaise Daniel 
Published: November 2022

A plant community may be considered as an assemblage of species whose chemical defenses against herbivores are more or less efficient. In the same way a community of phytophagous insects can be viewed as a group of consumers which are capable either of bypassing the plants’ chemical defenses, or of taking advantage of them. The inter-relations between the two communities result in an array of compromise solutions originating from the coevolution of plants and insects. The pros and cons of such a coevolutionary theory of community structure are discussed.
Particular attention is given to the following points : the concept of community structure, the major categories of toxiche-micals and digestibility-reducing substances involved in the «arms race» between plant producers and animal consumers, the evolutionary mechanisms implied in coevolution, the costs and benefits of the alternative adaptive strategies adopted by insect consumers (with particular emphasis on their bioenergetic implications), and the dynamic aspect of coevolution.
Whereas coevolution undoubtedly plays a role in plant-insect interactions, such a role should not be overemphasized. The well documented case of the moths living on various oak species highlights some obvious inconsistencies. Thus the coevolutionary theory of community structure should still be considered more as a useful working hypothesis rather than a well established fact.
Régime alimentaire d’un Lacertidae Eremias olivieri (Audouin) des îles Kerkennah en Tunisie
Authors: Nouira Saïd , Mou Yung-Ping 
Published: November 2022

The seasonal and local variations of the diet of the lizard Eremias olivieri (Lacertidae) were studied on the Kerkennah islands, off the coast of Tunisia. A total of 247 stomach was examined.
The wide range of the food items ingested, and the lack of a close relationship between the size of the prey and that of the predator, emphasizes the dietary opportunism of Eremias olivieri. Such a diet is considered as adaptive to the scarcity of food resources of the semi-desertic environment of the Kerkennah islands.
La prédation du Flamant rose Phoenicopterus ruber roseus par le Goéland leucophée Larus cachinnans en Camargue
Authors: Salathé Tobias 
Published: November 2022

Yellow-legged herring gulls prey on the Greater Flamingo breeding colony in the Camargue, taking both eggs and chicks. They kill young chicks in their nest and flightless young forming large aggregates («crèches»).
To rob nests the Yellow-legged herring gulls have developped a technique which forces the brooding flamingo to stand up. Once standing the brooding bird no longer defends its nest and the gull can take its content. Two or more gulls can cooperate when trying to catch larger chicks in a crèche. Such an attack causes young in the crèche to clump together and this may deter predation. Of the attacks observed 42 % were successful and 7 % unsuccessful, in spite of the perseverence of the predators. Fifty one percent were only brief interactions, the predators not pursuing their attack. Predatory episodes were most numerous during late afternoon until dusk, and between the end of May and the beginning of June when all nests held eggs or small chicks. As their size increased chicks became progressively more difficult to overcome. All predators were adult gulls nesting on the «Flamingo Island» itself. Attempts by some immature and juvenile birds were scarce. Marginal and late flamingo nests were more vulnerable to predation than those located in the center of the colony. In the Camargue, the Yellow-legged herring gull breed three weeks before the flamingo. The adaptive value of this time-lag between the breeding seasons of the two species is discussed.
The total number of eggs and chicks taken by the gulls is estimated to be at least 11 % of the eggs laid (without taking into account second clutches). Furthermore 32 % of the flamingo eggs (exclusive second clutches) were lost for other reasons, but eaten by the gulls afterwards. Flamingo eggs and chicks can account for up to 40 % of the food intake of the 14 pairs of Yellow-legged herring gulls breeding on the «Flamingo Island».
Flamingo predation by Yellow-legged herring gulls is known from the Camargue and Lake Rezaiyeh (Iran) only. Flamingos are very vulnerable to predation but the size of the colony and the close synchronisation of the breeding cycle may reduce its impact. Under present controlled conditions the Yellow-legged herring gulls do not appear to exert much influence on the population dynamics of the Camargue flamingos.
Evolution saisonnière de la taille des groupes chez le Chevreuil en milieu forestier
Authors: Bideau Eric , Vincent Jean-Paul , Maire F. 
Published: November 2022

Changes in the patterns of social grouping in the Roe Deer Capreolus capreolus (L.) were studied from 1977 to 1980 in three broadleaved forests of Northern France (Bassin Parisien).
Average herd size and seasonal changes in patterns of social groupings were the same in the three areas studied, though population densities were dissimilar and one of the forests was fenced.
During autumn and winter, 80 % of the animals lived in groups of 2 to 8 individuals, most of them being composed of a mother and her young of the year, or of a buck and a doe followed by their young. In spring and summer, on the other hand, only 40 % of the roe deer were found in groups, the most frequent of which were a buck and a doe, or a doe and her fawn.
Le régime alimentaire de la Chouette effraie, Tyto alba dans les Pyrénées-Orientales. Etude des variations écogéographiques
Authors: Libois R.M. , Fons Roger , Saint Girons Marie-Charlotte 
Published: November 2022

Correspondence analysis is used to study the variations of the diet of the Barn Owl (Tyto alba) in the eastern part of the Pyrénées, and their relationship with the various vegetation zones of the area. Nineteen samples of owl pellets (18561 prey items) were collected, together with information on the altitude, climate, vegetation and land-use of the sites where pellets were gathered.
In the eumediterranean zone, the Barn Owl preys mainly on Mus spretus, Pitymys pyrenaicus, Clethrionomys glareolus, Sorex «araneus» and S. minutus. Microtus arvalis is conspicuous by its absence.
Mus spretus is a typical eumediterranean species. Pitymys pyrenaicus, Microtus arvalis, Clethrionomys glareolus, Sorex «araneus» and S. minutus are conspicuously absent.
Pitymys duodecimcostatus, Suncus etruscus and Crocidura suaveolens cannot be considered as «indicator species» of the mediterranean biome. These small mammals take advantage of some man-made environmental changes to enter areas well outside the limits of the mediterranean bioclimate : e.g. cultivated fields with deep soils for Pitymys and dry-stone walls for Crocidurine shrews.
The strong correlation existing between ecoclimatic factors and prey selection emphasizes the opportunistic nature of Barn Owl’s predatory behaviour. The use of fossil pellets as an indicator of past environmental conditions of a given area is amply justified.
Les mammifères des îles de Provence et de Méditerranée Occidentale : un exemple de peuplement insulaire non-équilibré ?
Authors: Cheylan Gilles 
Published: November 2022

La faune mammalogique de 46 îles provençales, dont les surfaces varient de 0,2 à 1 254 ha, fut inventoriée de 1977 à 1982. Cinq espèces de mammifères terrestres seulement ont été trouvées, parmi lesquelles le Rat noir est la plus largement répandue (Rat noir Rattus rattus, Souris domestique Mus musculus, Mulot sylvestre Apodemus sylvaticus, Lapin Oryctolagus cuniculus et Musaraigne des jardins Crocidura suaveolens). Ce peuplement a été comparé à celui de 15 îles de Méditerranée occidentale, considérablement plus étendues (0,15 à 25 709 km²), avec lequel il montre une grande affinité. Les conclusions suivantes peuvent être dégagées de cette analyse :
1. — La pente de la courbe surface-richesse est plus faible (z = 0,20) que celle habituellement obtenue pour les îles.
2. — Il n’y a pas de corrélation entre la richesse et l’éloignement.
3. — La richesse spécifique a été 2 à 5 fois accrue depuis que l’homme s’est installé dans ces îles, au début du Néolithique.
4. — Les espèces carnivores ne sont pas moins abondantes, par rapport au total des espèces, que sur le continent, contrairement à ce qui est habituellement observé dans les communautés insulaires de mammifères en équilibre.
5. — La faune moderne, qui provient essentiellement de milieux secondaires, remplace entièrement la faune archaïque, dont toutes les espèces étaient endémiques. 6. — L’homme est incontestablement le principal propagateur de cette faune moderne.
En conclusion, il apparaît que les peuplements étudiés sont actuellement non-équilibrés, car l’homme y a introduit de nombreuses espèces nouvelles qui ont saturé ces communautés. On peut prévoir que celles-ci retourneront vers l’équilibre dynamique, par le biais d’extinctions, après un temps de relâchement qui semble plus long que chez les oiseaux.
Régime alimentaire du Héron garde-bœuf à la limite de son expansion géographique récente
Authors: Bredin Denis 
Published: November 2022

A brief review of the Cattle Egret’s diet in the World shows that it is predominantly insectivorous.
In the Camargue, the feeding biotopes differ throughout the year. Meadows and stubble fields are used in winter, whereas in spring and summer they feed in wetlands (marshes and flooded rice fields).
The diet has been determined by direct observations on the feeding ground, and varies greatly from one season to another. During the summer, mainly insects are taken (Orthoptera and horse-flies) with quite a lot of frogs. In winter the Cattle Egret becomes gradually carnivorous ; earthworms and rodents (voles and mice) form the main prey items, almost exclusively rodents being taken during periods of dry and frosty weather. The variation in prey «accessibility », explains the relationship between the use of feeding biotopes and the diet. During the winter only the easily accessible preys are caught in the only biotopes where they occur whilst in summer the abundance and variety of prey items available allows the cattle egrets to choose its usual prey where this is most abundant.
The extraordinary adaptive capacity concerning the feeding habits, allows the species to breed in the Camargue, and, far more surprising, to winter. The expansion in Europe has certainly not yet stopped and the species has recently bred and also wintered in the West of France.
Un primate granivore : le Colobe noir dans la forêt du Gabon ; potentialité d’évolution du comportement alimentaire
Authors: Harrison M.J.S. , Hladik C.M. 
Published: November 2022

This paper presents preliminary data on the feeding strategy of the Black colobus, Colobus satanas, in central Gabon. The study was conducted in the Réserve de la Lopé, using frequency method and systematic monthly samples to quantify the diet on one focal group of monkeys.
The Black colobus feeds predominantly on immature seeds, unlike most of its folivorous relatives, while the consumption of young leaves is second in importance. Despite considerable variation in resource availability, seeds always dominate in the monthly diet. An increase in young leaf consumption was associated with an abundance of flush leaves, but also a reduction in seed availability ; a subsequent seasonal peak of flush leaves showed rm increase in their contribution to the diet, as seeds were also commonly available. Mature leaves were rarely eaten, and their occurence in the diet could explain some aspects of concomitant geophagy.
Seasonal variation in diet and resources is compared with that of other primates of North-East Gabon : availability of foliage also partly influences consumption, but the dependence largely on fruit pulp and lack of seeds in the diet contrasts sharply with Black colobus. A similar biomass of Cercopithecidae is found in North-East Gabon where colobus are absent, and Lopé where one might have expected a larger biomass if the Black colobus had been a true folivore.
Folivorous and frugivorous dietary strategies are contrasted on the basis of energetically economical vs expensive feeding. The Colobinae tend towards economical feeding strategies with their specialized digestive apparatus, but C. satanas represents a contrast, favoring an expensive seed-eating strategy. A hypothetical mechanism for the behavioural regulation of these strategies is discussed, based on conditioning principles. With such behavioural flexibility, we suggest that seed-eating by Black colobus may be a positive choice rather than a result of selective pressures against folivory.
Surface, distribution et diversité des principaux milieux de Camargue. Leur évolution de 1942 à 1984
Authors: Lemaire Sophie , Tamisier Alain , Gagnier François 
Published: November 2022

The changes in surface area of the major habitats of the Camargue, between 1942 and 1984, were quantified, using aerial photographs taken during this time interval, as well as ground checks. Whereas «natural areas» covered 67 % of the Camargue in 1942, this percentage has now been reduced by more than one third. 40 000 ha were lost in 40 years, i.e. 1 000 ha per year on the average. «Artificial» areas now predominate, and presently cover 56 % of the Camargue (145 000 ha). They are made up of crop lands (52 000 ha), salt marshes (21 000 ha), and industrial areas (8 600 ha). The «natural areas» left are mostly marshes managed for hunting purposes (18 000 ha), large permanent ponds (14 500 ha), «sansouires» (12 000 ha), prairies (4 800 ha), and temporary halomorph ponds (3 000 ha).
Besides being reduced in size, the «natural areas» are now much more scattered than the «artificial» areas. Their barycentres are all located in the centre of the delta, and they did not change place during the last forty years — except for salt marshes and temporary ponds.
Organisation spatiale et déplacements des Chats forestiers adultes (Felis silvestris, Schreber, 1777) en Lorraine
Authors: Stahl P. , Artois Marc , Aubert Michel F.A. 
Published: November 2022

L’organisation spatiale et les déplacements de chats forestiers adultes (F. silvestris) ont été étudiés pendant 3 ans en Lorraine, à partir de la fin de l’année 1981.
Les femelles utilisent des domaines vitaux d’environ 200 ha variant peu individuellement ou saisonnièrement. Les superficies des domaines vitaux des mâles varient d’un facteur 1 à 5 (220 à 1 270 ha) selon les individus. Les plus grands domaines vitaux sont utilisés par des chats sédentaires, tandis que les plus petits le sont par un chat nomade et un jeune mâle. Il existe une corrélation linéaire positive entre l’indice d’activité locomotrice (IAL) mesuré en km parcourus par 24 h et la superficie des domaines vitaux saisonniers.
Cette augmentation de l’IAL n’est cependant pas suffisante pour permettre aux mâles sédentaires de parcourir leur vaste domaine aussi intensivement que les femelles et les autres mâles. L’exploitation de ces grands domaines se fait à un rythme pluri-journalier plus ou moins marqué selon les saisons.
Les femelles semblent être distribuées régulièrement sur le site d’étude. Les domaines vitaux de certains mâles se superposent à ceux de 3 à 6 femelles. Les sites de repos sont utilisés par les individus des 2 sexes et les zones de chasse sont situées à proximité des sites de repos.
Il semble que la répartition, la superficie des domaines vitaux et les mouvements des femelles dépendent principalement des ressources alimentaires en relation avec l’élevage des jeunes. Ces mêmes variables pourraient dépendre chez les mâles de la distribution des femelles en raison d’une compétition intrasexuelle pour celles-ci. L’organisation spatiale développée par F. silvestris en Lorraine est différente de celle qui a été décrite en Ecosse. Cette variabilité pourrait être due à la différence de nature des ressources alimentaires utilisées.
La formation de couples hivernaux chez le Petit Bec-en-Fourreau (Chionis minor) et sa signification biologique
Authors: Verheyden Christophe 
Published: November 2022

Le comportement territorial, sexuel et alimentaire d’une population repro- ductrice de petits Bec-en-fourreau (Chionis minor) a été suivie pendant 13 mois sur une des îles de l’archipel Crozet, Sud-Ouest de l’Océan Indien.
Le passage de la période de reproduction à la période hivernale est marqué par d’importantes modifications des conditions climatiques et alimentaires, qui induisent une redistribution de l’espace et des ressources au sein de cette population.
Dans les milieux les plus riches (colonies de manchots royaux), presque tous les couples restent unis et conservent leur territoire, sans modifier leur régime alimentaire.
Dans les milieux les plus appauvris (colonies de gorfous), seuls quelques oiseaux restent sur place (surtout les femelles), mais étendent leur territoire et modifient leur régime alimentaire. Les autres oiseaux se déplacent vers les milieux les plus riches qu’ils prospectent généralement en groupes, mais une part non négligeable d’entre-eux (30 %) parvient à s’octroyer un nouveau territoire et à s’associer à un nouveau partenaire (apparemment un adulte non-reproducteur dans le cas général). Ces couples hivernaux, dont on ne connaît aucun équivalent, se forment après la reproduction (parfois moins de 15 jours après l’envol des jeunes) et peuvent se maintenir pendant plus de 6 mois. Tous se dissocient au moment de la reprise de la reproduction où l’on assiste à la reformation des couples reproducteurs. L’apparente absence d’intérêt reproductif d’une telle association est discutée et son intérêt alimentaire suggéré.
L’activité de ponte de la Tortue Luth Dermochelys coriacea (Vandelli, 1761), pendant la saison 1988 en Guyane française
Authors: Fretey Jacques , Girondot Marc 
Published: November 2022

Approximately 48 000 nests of leatherbacks Dermochelys coriacea were counted between March and August 1988 on the Ya:lima:po-Les Hattes beach, French Guiana. This figure represents a new world record for the species. The use of this beach by ovipositing females reached its peak in June, when from 200 to over 1 000 females per night were observed coming ashore.
Marked females were observed laying clutches 8 and 9 times in succession, at intervals of 8 to 32 days : seven females probably laid up to 12 different clutches during the same season.
The total number of leatherbacks nesting at this French Guiana site can be estimated at 14 700-15 300 individuals. The population of leatherbacks nesting in French Guiana is probably larger than previously estimated. The possibility of the nesting cycle of leatherbacks being irregular is also raised.
La prédation joue-t-elle un rôle dans la régression de l’Hypolais ictérine Hippolais icterina ?
Authors: Faivre Bruno 
Published: November 2022

An attempt was made to identify the causes of the population decline of the Icterine Warbler Hippolais icterina in Burgundy, where this species is sympatrie with the Melodious Warbler H. polyglotta. The study was carried out at 18 different sites South East of Dijon (21, France). The two sibling species were sympatric at 13 sites, and H. icterina was allopatric at the remaining three. Furthermore, the breeding performances of the Melodious Warbler were also studied at two other allopatric sites randomly selected in the surrounding areas.
When sympatric, the percentage of brood failure was significantly higher (p < 0.05) for H. icterina (62.2 %) than for H. polyglotta (37.5 %). This could be explained by behavioural differences of importance to predators : the number of feeding visits and the relative shyness of the adults. Feeding frequency averaged 3.03 per 10 min. in the Icterine Warbler, versus 2.33 for the Melodius Warbler. Furthermore, the Melodious Warbler was significantly (p < 0.05) shyer than the Icterine Warbler.
The percentage of brood failure was also found to increase when the two species bred close to each other (from 37.5 % to 67.5 % for H. icterina, and from 20.0% to 42.5% for H. polyglotta). Such a strong increase in brood failure apparently results of the greater density and clumping of the breeding territories when the two species are sympatric. These high density areas should indeed be more attractive to predators than the lower density of nests found in allopatric areas.
These findings suggest the following explanation for the decline of H. icterina. The high density of breeding pairs in areas where the two species are sympatric leads to a higher susceptibility of their nests to predactors. On the other hand, the difference in shyness between the two species leads to a greater vulnerability of H. icterina. The end result is a decline in numbers of the Icterine Warbler population.