[Distinctive morphofunctional features of the bill and hyoid apparatus of turacos (Aves, Musophagidae): relations with frugivory]. / Les particularités morphofonctionnelles des appareils du bec et hyoïdien chez les touracos (Aves, Musophagidae): relations avec la frugivorie.

The present study points to morpho-anatomical features that allow vegetarian but mainly frugivorous turacos to fill at best their specific feeding requirements. Mechanisms are analysed which the bird can use to detach a fruit and avoid it rolls out of the bill. It is also examined how vegetable items can be processed particularly when they have to be cut, and what can facilitate their ingestion particularly when they are fruits that have to be swallowed entirely and are large and/or have dry or fibrous skin or flesh. The skeletal and muscular anatomy of the bill and hyoid apparatus is described in details and illustrated. The particularly short and stout bill coupled with a relatively simple system of aponevroses of the adductors reflects a trade-off between two important jaw functional requirements: huge efforts for clamping, and a wide opening for plucking, processing and swallowing relatively large fruit. The clearly oblique orientation of the modified outer adductor seems an adaptation to the detachment of fruits. The os uncinatum, particularly developed in this bird family, is interpreted as maintaining transversal stability, particularly when jaws act as a pair of scissors. Most food items being processed near the base of the bill, mechanisms have been developed which contribute to overcome the risk of breakage at the level of the prokinetic hinge because of a vertically oriented force there.

[Morphofunctional analysis and trophic adaptations: the case of bill apparatus of Old World flycatchers]. / Analyse morphofonctionnelle et adaptations trophiques: le cas de l'appareil du bec des gobe-mouches de l'Ancien Monde.

A morphofunctional analysis of the bill apparatus was conducted on some African forest flycatchers (Muscicapidae, Platysteiridae, Monarchidae) in relation to detailed eco-ethological data available on these species. The aim was to evaluate relationships between anatomical structures and habitat constraints and also identify the most pertinent trophic adaptations. If forest Muscicapidae have essentially conserved the generalized passerine structures and occupy open-habitat niches in the forest, Platysteiridae and Monarchidae have adapted to forest conditions and show a key-adaptation based on specific changes in the structure of the bill apparatus in response to particular light patterns and habitat clogginess, constraints that require speed and precision for the capture of prey and protection of the skull against collisions.

[Effect of the moon on the nocturnal postnuptial migration of the skylark Alauda arvensis L. in France]. / Effet de la lune sur la migration postnuptiale nocturne de l'alouette des champs Alauda arvensis L. en France.

Night-migrating skylarks (Alauda arvensis) were captured during four successive autumns in France. The study aimed at detecting a possible influence of the lunar cycle on the nocturnal migration of this species. Though nocturnal postnuptial migration of the skylarks can occur during every phase of the moon, main nocturnal movements occurred when the moon was in its waxing gibbous phase. This phase gives the best conditions for migration because from the very beginning of night, it provides the necessary horizon for individuals to navigate and its light allows the use of topographic cues. In addition it allows the species to benefit from optimal conditions of illumination for almost a week.

Fruit characters as a basis of fruit choice and seed dispersal in a tropical forest vertebrate community.

Interactions between a large community of vertebrate frugivore-granivores (including 7 species of large canopy birds, 19 species of rodents, 7 species of ruminants, and 6 species of monkeys), and 122 fruit species they consume, were studied for a year in a tropical rainforest in Gabon.The results show how morphological characters of fruits are involved in the choice and partitioning of the available fruit spectrum among consumer taxa. Despite an outstanding lack of specificity between fruit and consumer species, consideration of simple morphological traits of fruits reveals broad character syndromes associated with different consumer taxa. Competition between distantly related taxa that feed at the same height is far more important than has been previously supposed. The results also suggest how fruit characters could have evolved under consumer pressure as a result of consumer roles as dispersers or seed predators. Our analyses of dispersal syndromes show that fruit species partitioning occurs more between mammal taxa than between mammals and birds. There is thus a bird-monkey syndrome and a ruminant-rodent-elephant syndrome. The bird-monkey syndrome includes fruit species on which there is no pre-dispersal seed predation. These fruits (berries and drupes) are brightly colored, have a succulent pulp or arillate seeds, and no protective seed cover. The ruminant-rodent-elephant syndrome includes species for which there is pre-dispersal predation. These fruits (all drupes) are large, dull-colored, and have a dry fibrous flesh and well-protected seeds.

[Hepatocystis brosseti n. sp. Haemproteidae, parasite of Epomops franqueti, Pteropinae, in Gabon]. / Hepatocystis brosseti n. sp., Haemoproteidae, parasite d'Epomops franqueti, Pteropinae, au Gabon.

Epomops franqueti (Pteriopinae) trapped around Makokou (Gabon) are frequently infected with Hepatocystis brosseti n. sp. Blood smears and tissue sections were made; all schizonts were found in the liver except a single one in the spleen. In liver, near maturity the schizonts are extracellular, convoluted, medium sized (250 mu) and filled with abundant colloidal substance.