The marine birds comprising the order Procellariiformes are an ancient and diverse assemblage. A large proportion are both nocturnal and burrow-nesting at their breeding colonies, where in sharp contrast to their behaviour at sea, they are highly vociferous. Virtually nothing is known regarding the adaptive features of this process. Various aspects of vocal behaviour have therefore been investigated from 1981 to 1983 for seven species at breeding stations in both the boreal and sub-tropical North Atlantic Ocean. In addition, the problem of how these birds return to their correct burrows at night has been considered. A detailed study was conducted on the Manx Shearwater Puffinus puffinus. Various approaches showed that immatures contribute most to the calling heard. Males establish and defend burrows, but both sexes partake in aerial calling. Calling at ground level serves both sexual and territorial functions, whereas aerial calling is probably mainly concerned with sexual advertisement. Some males are more silent in flight than others. These probably represent birds as yet without burrows, perhaps the youngest age classes. Flighting activity probably expedites the acquisition of burrows and mates in these birds which are awkward on land, and aerial calling probably improves signalling efficiency in attracting mates. Six other species (Bulweria bulwerii, Calonectris diomedea, Puffinus assimilis, Hydrobates pelagicus, Oceanodroma castro, Pelagodroma marina) were studied. As with Puffinus puffinus, sexual differences in voice exist for all except Bulweria and Pelagodroma, which also lack aerial calls. Thus a functional link exists between flight calls and their sexual divergence. Selection probably favours such divergence in species where males leave burrows to display in flight; the sexual identity of those species whose males do not is unambiguous as they remain in burrows and call. The calls of Puffinus puffinus and Hydrobates pelagicus were compared at local and regional levels. Divergence exists between but not within islands. Vocal drift in Puffinus puffinus is also apparent after several years. The calls of the nocturnal Procellariiformes are reviewed and discussed in relation to their systematics. The potential use of calls in petrel systematics is also evaluated and shown to be useful. Observations on Puffinus puffinus showed that olfactory and auditory cues are not used for burrow homing. Experiments also confirmed this, and point to sufficient visual development in this species, although other senses may be emphasised in different ecological situations.

Os albatrozes e petréis (Procellariiformes) são aves oceânicas e migratórias de grande interesse conservacionista. Neste trabalho foram estudadas duas classes de poluentes bastante conhecidos por afetarem negativamente as aves marinhas: os poluentes orgânicos persistentes e os plásticos. Bifenilos policlorados (PCBs) e pesticidas organoclorados foram detectados no tecido adiposo, fígado e músculo de oito espécies de Procellariiformes. Apesar da grande variabilidade intraespecífica nas concentrações, os perfis de PCBs e pesticidas organoclorados foram semelhantes entre os indíviduos, com predôminância de PCBs penta, hexa e heptaclorados e do p´p-DDE. A condição corporal se mostrou um fator importante na variação e redistribuição dos organoclorados nos tecidos das aves. As análises de isótopos estáveis de carbono e nitrogênio no fígado e músculo das aves mostraram que a dieta não foi suficiente para explicar as concentrações de organoclorados nas espécies estudadas e reforçaram a influência de fatores como idade, distribuição e especifidade da dieta na contaminação por estes compostos em aves marinhas. PCBs e pesticidas organoclorados foram detectados em pellets e fragmentos plásticos encontrados no trato digestório das aves estudadas, com perfis semelhantes aos encontrados nos tecidos dos Procellariiformes. A ocorrência de poluentes orgânicos em plásticos evidencia a capacidade destes de adsorver e transportar estes compostos e reforça o potencial dos plásticos como uma fonte adicional de contaminação para os animais que os ingerem, como as aves marinhas. / Albatrosses and petrels (Procellariiformes) are migratory oceanic birds of considerable conservational interest. The aim of the present study was to evaluate two classes of pollutants that negatively affect seabirds: persistent organic pollutants and plastics. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were detected in the adipose tissue, liver and muscle of eight species of Procellariiformes. Although organochlorine concentrations exhibited a high degree of intra-species variability, the profiles of PCBs and OCPs were similar among the individuals, with predominance of penta, hexa and heptachlorobiphenyls and p´p-DDE. Body condition was an important factor in the variation and redistribution of organochlorine compounds in the tissues of the birds. Stable isotope analysis of carbon and nitrogen in the liver and muscle revealed that diet alone was insufficient to explain the organochlorine concentrations in the species studied, suggesting the influence of factors such as age, distribution and diet specificity regarding organochlorine contamination in seabirds. PCBs and OCPs were detected in plastic fragments and pellets found in the digestive tract of Procellariiformes, with profiles very similar to those found in the tissues of the birds. The occurrence of organic pollutants in plastics demonstrates their ability to adsorb and transport these compounds and underscores the potential of plastics as an additional source of contamination in organisms that ingest these products, such as seabirds.

Os albatrozes e petréis (Procellariiformes) são aves oceânicas e migratórias de grande interesse conservacionista. Neste trabalho foram estudadas duas classes de poluentes bastante conhecidos por afetarem negativamente as aves marinhas: os poluentes orgânicos persistentes e os plásticos. Bifenilos policlorados (PCBs) e pesticidas organoclorados foram detectados no tecido adiposo, fígado e músculo de oito espécies de Procellariiformes. Apesar da grande variabilidade intraespecífica nas concentrações, os perfis de PCBs e pesticidas organoclorados foram semelhantes entre os indíviduos, com predôminância de PCBs penta, hexa e heptaclorados e do p´p-DDE. A condição corporal se mostrou um fator importante na variação e redistribuição dos organoclorados nos tecidos das aves. As análises de isótopos estáveis de carbono e nitrogênio no fígado e músculo das aves mostraram que a dieta não foi suficiente para explicar as concentrações de organoclorados nas espécies estudadas e reforçaram a influência de fatores como idade, distribuição e especifidade da dieta na contaminação por estes compostos em aves marinhas. PCBs e pesticidas organoclorados foram detectados em pellets e fragmentos plásticos encontrados no trato digestório das aves estudadas, com perfis semelhantes aos encontrados nos tecidos dos Procellariiformes. A ocorrência de poluentes orgânicos em plásticos evidencia a capacidade destes de adsorver e transportar estes compostos e reforça o potencial dos plásticos como uma fonte adicional de contaminação para os animais que os ingerem, como as aves marinhas. / Albatrosses and petrels (Procellariiformes) are migratory oceanic birds of considerable conservational interest. The aim of the present study was to evaluate two classes of pollutants that negatively affect seabirds: persistent organic pollutants and plastics. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were detected in the adipose tissue, liver and muscle of eight species of Procellariiformes. Although organochlorine concentrations exhibited a high degree of intra-species variability, the profiles of PCBs and OCPs were similar among the individuals, with predominance of penta, hexa and heptachlorobiphenyls and p´p-DDE. Body condition was an important factor in the variation and redistribution of organochlorine compounds in the tissues of the birds. Stable isotope analysis of carbon and nitrogen in the liver and muscle revealed that diet alone was insufficient to explain the organochlorine concentrations in the species studied, suggesting the influence of factors such as age, distribution and diet specificity regarding organochlorine contamination in seabirds. PCBs and OCPs were detected in plastic fragments and pellets found in the digestive tract of Procellariiformes, with profiles very similar to those found in the tissues of the birds. The occurrence of organic pollutants in plastics demonstrates their ability to adsorb and transport these compounds and underscores the potential of plastics as an additional source of contamination in organisms that ingest these products, such as seabirds.

La communication chimique, c'est-à-dire le transfert d'information d'un émetteur à un receveur via signaux moléculaires, est présente dans tous les embranchements animaux. Longtemps négligée, l'étude récente de ces processus chez les oiseaux suggère que les signaux chimiques (ou ‘chémosignaux') ont une fonction beaucoup plus importante que longtemps anticipée. Les pétrels hypogés (ordre: procellariiformes) fournissent un modele approprié pour examiner ces questions. Ces oiseaux marins possèdent en effet une neuro-anatomie olfactive développée, une odeur musquée caractéristique et des traits d'histoire de vie favorisant l'évolution d'une composante olfactive aux comportements sociaux. En utilisant une combinaison de méthodes, existantes et spécifiquement développées, d'écologie comportementale, de chimie analytique et de statistique multivariées, nous avons examiné le rôle des chémosignaux dans l'écologie du pétrel bleu (Halobaena caerulea), un pétrel hypogée de l'océan Subantarctique. Nous avons ainsi démontré que la sécrétion uropygiale des pétrels bleus, leur source principale de substances chimiques exogènes, contient des informations sociales telles que l'espèce, le sexe et l'identité (i.e. une signature chimique). De plus, cette information est encore présente, de manière quasi-identique, sur le plumage des oiseaux et participe donc vraisemblablement à l'odeur des individus. En termes de perception des signaux chimiques, nous avons établi que les pétrels bleus sont capables de percevoir et distinguer entre les odeurs de différentes espèces de pétrels, ainsi qu'entre les odeurs de différents conspécifiques. Cependant, aucune capacité de discrimination olfactive intersexuelle n'a été observée. Longtemps restreinte aux comportements de recherche alimentaire et d'orientation, l'étude de l'olfaction aviaire est en pleine expansion pour désormais intégrer des aspects sociaux. Nos résultats fournissent en ce sens une première étude multidisciplinaire du sujet. La clarification de l'origine, de la nature et de la fonction de la communication chimique chez les oiseaux devrait avoir des implications éco-évolutives majeures pour la compréhension de leur biologie. / Chemical communication, the transfer of information from an emitter to a receiver via molecular signals, occurs in all animal phyla. Although such processes have been largely overlooked in birds, recent results suggest that chemical signals may play a more significant role than previously assumed in the social lives of birds. Procellariiform seabirds, and burrow-nesting petrels in particular, are appropriate models to investigate these questions. They indeed possess a well-developed olfactory anatomy, a noticeable musky scent and a life-history which favours the evolution of olfactory-mediated social behaviours (Chapter1).We have explored the role of chemical signals in the ecology of the blue petrel (Halobaena caerulea), a burrow-nesting seabird from the Subantarctic Ocean, using existing and innovative methods from field ornithology, analytical chemistry and multivariate statistics (Chapter 2). We first demonstrate that the uropygial secretions of these birds, their main source of endogenous chemical substances, contain social information including species, sex and individual identity (i.e. a chemical signature). We also show evidence that these signals are still present, in a virtually identical form, on the plumage of the birds and are thus a likely contributor to the animals' scent (Chapter 3). Furthermore, we show that blue petrels, as receivers of the sociochemical information, are able to discriminate between the odours from different species, and between the odours of different conspecifics. There is however no evidence of olfactory capabilities of sex discrimination in this species ( Chapter 4).The study of avian olfactory behaviours, historically limited to foraging and orientation (Chapter 5), is rapidly expanding to incorporate social functions. In this regard, our results provide the first multidisciplinary case-study of avian chemical communication. The elucidation of the origin, nature and function of chemical communication in birds has major eco-evolutionary implications for our understanding of avian ecology (Chapter 6).