Jacques Vielliard

Behaviourally driven gene expression reveals song nuclei in hummingbird brain.

Hummingbirds have developed a wealth of intriguing features, such as backwards flight, ultraviolet vision, extremely high metabolic rates, nocturnal hibernation, high brain-to-body size ratio and a remarkable species–specific diversity of vocalizations. Like humans, they have also developed the rare trait of vocal learning, this being the ability to acquire vocalizations through imitation rather than instinct. Here we show, using behaviourally driven gene expression in freely ranging tropical animals, that the forebrain of hummingbirds contains seven discrete structures that are active during singing, providing the first anatomical and functional demonstration of vocal nuclei in hummingbirds. These structures are strikingly similar to seven forebrain regions that are involved in vocal learning and production in songbirds and parrots—the only other avian orders known to be vocal learners. This similarity is surprising, as songbirds, parrots and hummingbirds are thought to have evolved vocal learning and associated brain structures independently, and it indicates that strong constraints may influence the evolution of forebrain vocal nuclei.

Composition and dynamics of the bird community of mata de Santa Genebra, Campinas, São Paulo, Brazil

A quali-quantitative survey of avifauna was earried out at the Santa Genebra forest reserve (MSG) in order to evaluate the current state of conservation of this important conservation area in the interior of Sao Paulo Stale. The qualilative survey recorded 134 species and the quantitativo survey through unlimited distance point counts recorded the abundance of 97 species. The low number of species recorded in both surveys was due to the small size (251 ha) and the high degree of isolation of the MSG. These factors plus the extensivo degradation of the forest cover prevent recolonization of extinct species and allow the expansion of some species tolerant to disturbance. The quantitative survey showed some species with an unusually high abundance index. The abundance of most species at MSG is higher whon compared with other areas of similar vegetation which are not fragmented and isolated, There was no striking seasonal variation in the number of birds recorded. These caracteristics could be interpreted as resulting from the density compensation phenomenon. The structure of the bird community of MSG resembles that from an island with low number of species but overall density similar to that of the mainland, leading to a higher density per species. The process responsible for these patterns seems to be related to the habitat appropriateness, mainly because the MSG is completely isolated from other forest arcas.

Sedentary life style of Neotropical sedge wrens promotes song imitation

To what extent has the style of song development among songbirds coevolved with other life history strategies? Among Cistothorus wrens in North America, it seems that sedentary or site-faithful habits of marsh wrens, C. palustris, favour song imitation, but seminomadic habits of sedge wrens, C. platensis, favour song improvisation, whereby each male generates a large but unique song repertoire. In this study, we tested whether more sedentary populations of sedge wrens in the Neotropics would imitate songs. At our primary study site near Cartago, Costa Rica, breeding birds were colour-banded during 1995 and 1996, and follow-up surveys revealed that the birds remained at this site the year round. Extensive tape recording and analysis of songs showed that males had large song repertoires (200-300+ songs), and that many songs were shared among neighbouring males. In addition, males only 27 km distant, at La Pastora, used different songs. Furthermore, matched countersinging, in which two males answer each other with identical song types, was recorded near Brasilia, in Brazil. The sharing of songs among permanent neighbours, microgeographical variation in song, and matched countersinging can be achieved only through song imitation, thus revealing a striking difference in the style of song development among different populations of the sedge wren. In the Neotropics, having predictable neighbours throughout life appears to have favoured song imitation, so that individuals can interact using a common, learned code typical of the local population; among more mobile populations in North America, however, individuals improvise large repertoires of species-typical songs, thereby enabling singing males to communicate with any individual, no matter what the population of origin. Strategies of song development must correlate with life history features, and further surveys are needed to make sense of the great diversity of singing behaviours among songbirds. Copyright 1999 The Association for the Study of Animal Behaviour.

Singing in the rain forest: how a tropical bird song transfers information.

How information transmission processes between individuals are shaped by natural selection is a key question for the understanding of the evolution of acoustic communication systems. Environmental acoustics predict that signal structure will differ depending on general features of the habitat. Social features, like individual spacing and mating behavior, may also be important for the design of communication. Here we present the first experimental study investigating how a tropical rainforest bird, the white-browed warbler Basileuterus leucoblepharus, extracts various information from a received song: species-specific identity, individual identity and location of the sender. Species-specific information is encoded in a resistant acoustic feature and is thus a public signal helping males to reach a wide audience. Conversely, individual identity is supported by song features susceptible to propagation: this private signal is reserved for neighbors. Finally, the receivers can locate the singers by using propagation-induced song modifications. Thus, this communication system is well matched to the acoustic constraints of the rain forest and to the ecological requirements of the species. Our results emphasize that, in a constraining acoustic environment, the efficiency of a sound communication system results from a coding/decoding process particularly well tuned to the acoustic properties of this environment.

Efficiency of playback for assessing the occurrence of five bird species in Brazilian Atlantic Forest fragments

Playback of bird songs is a useful technique for species detection; however, this method is usually not standardized. We tested playback efficiency for five Atlantic Forest birds (White-browed Warbler Basileuterus leucoblepharus, Giant Antshrike Batara cinerea, Swallow-tailed Manakin Chiroxiphia caudata, Whiteshouldered Fire-eye Pyriglena leucoptera and Surucua Trogon Trogon surrucura) for different time of the day, season of the year and species abundance at the Morro Grande Forest Reserve (South-eastern Brazil) and at thirteen forest fragments in a nearby landscape. Vocalizations were broadcasted monthly at sunrise, noon and sunset, during one year. For B. leucoblepharus, C. caudata and T. surrucura, sunrise and noon were more efficient than sunset. Batara cinerea presented higher efficiency from July to October. Playback expanded the favourable period for avifaunal surveys in tropical forest, usually restricted to early morning in the breeding season. The playback was efficient in detecting the presence of all species when the abundance was not too low. But only B. leucoblepharus and T. surrucura showed abundance values significantly related to this efficiency. The present study provided a precise indication of the best daily and seasonal periods and a confidence interval to maximize the efficiency of playback to detect the occurrence of these forest species.

How a simple and stereotyped acoustic signal transmits individual information: the song of the White-browed Warbler Basileuterus leucoblepharus

The White-browed Warbler Basileuterus leucoblepharus, a common bird of the BrazilianAtlantic forest, emits only one distinct song type in the context of territorial defense. Individual or neighbor-stranger recognition may be more difficult when birds share similar songs. In fact, the analysis of songs of different individuals reveals slight differences in the temporal and the frequency domains. Effectively, a careful examination of the signals of different individuals (21) by 5 complementary methods of analysis reveals first, that one or two gaps in frequency occur between two successive notes at different moments of the song, and second, that their temporal and frequency positions are stereotyped for each individual. Playback experiments confirm these findings. By propagation experiments, we show that this individual information can be only transmitted at short range (< 100 m) in the forest. In regard to the size and the repartition of territories, this communication process appears efficient and adaptive.

Bird community as an indicator of biodiversity: results from quantitative surveys in Brazil

This short review presents the results obtained in several localities of Brazil on the composition of forest bird communities. Data were collected since the late 80s, after we introduced a new methodology of quantitative survey, based on acoustic identification and unlimited-radius point census. Although these data are still scattered, they show uniquely precise and coherently comparative patterns of composition of forest bird communities. Our methodology has the advantage of being absolutely non-disturbing, highly efficient in the field and immediately processed. Results confirm that the structure of a bird community is a good indicator of biodiversity, particularly useful where biodiversity is high. Many of these data are available only in unpublished dissertations and abstracts of congress communications, or are being analysed. A cooperative program is needed to promote new surveys and publish their results, as a contribution for measuring and monitoring biodiversity, especially in complex endangered habitats.

Composição da avifauna em duas matas ciliares na bacia do rio Jacaré-Pepira, São Paulo, Brasil

A quali-quantitative survey was carried out in two riparian forests fragmente (approximately 40 ha each) at Jacare-Pepira river. Our intention was to characterize its bird community conceming richness, abundance and species occurrence in these areas. The qualitative survey showed 130 species at Santa Elisa (Brotas, Sao Paulo) and 151 at Morro Chato (Dourado, Sao Paulo), whereas the quantitative survey revealed the presence of 69 and 75 species at Santa Elisa and Morro Chato, respectively. The small size and the isolation might be responsible for the low number of species found. Observing the abundance index values (IPA) we realize that there are a few number of species with a high IPA on the one hand, while on the other there is a large number of species with intermediate and low IPA rates. A high detection coefficient (vocalization), low predatoiy rates and competition might have contributed for the higher abundance values found among these species. Furthermore, we have also registered species which are abundant in a fragment, but absent in the other, which might be explained by initial exclusion or local extinction. In spite of the riparian forests being protected by law, its clearing process has not stopped yet. Therefore, the study of this bird community is of uppermost impoitance for the elaboration of both conservation and management projects regarding these areas.

Uma nova espécie de Glaucidium (Aves, Strigidae) da Amazônia

A new species of Pygmy-Owl, genus Glaucidium, is described from the Amazonian forest. It is separated from G. minutissimum, now restricted to South-eastern Brazil and Central America, by its voice and shorter tail. The type-locality is from Rondonia, but the species seems widespread, with geographical races awaiting description from northern Para, Northeastern Brazil, and possibly Central America. A detailed survey of this overlooked canopy-living Pygmy-Owl is under way.

Vocal Repertoire of the Yellow-Faced Parrot (Alipiopsitta xanthops)

Abstract We describe the vocal repertoire of the Yellow-faced Parrot (Alipiopsitta xanthops) from recorded vocalizations and also flock sizes in Brasília (Brazil) during 2006. Vocal communication signals are both long-range and short-range sounds. We describe seven call types: flight call (long-range), long-range alarm call, congregation call (long-range), two agonistic calls (long-range/short-range), sentinel call (short-range), and a short-range alarm call. The flight call is equivalent to the functional song and contains the species-specific recognition code. Flight calls may also be uttered when perched and, when in quick series, function as long-range alarm calls. Long-range alarm calls become a high intensity congregation signal when several individuals overlap and, despite degradation and attenuation, may contain the species-specific code over distances of 800 m. The average (±SD) feeding flock size was 7.7 ± 8.2 individuals (n  =  116) while the roosting flock size was 79.1 ± 10.5 individuals (n  =  7). Short-range calls maintain communication while minimizing detection. High intensity vocalizations allow long-range communication, improving feeding efficiency through use of large areas and stimulating late afternoon roost congregations. Low intensity vocalizations maintain communications without providing the position of the parrot.