Le troglodyte est un oiseau chanteur forestier qui défend son territoire par des chants discrets. Les mâles voisins ayant des territoires adjacents forment des réseaux de communication acoustique. La mise en place, la dynamique et l’évolution dans le temps de ces réseaux en conditions naturelles sont peu connus.Par des enregistrements ciblés et continus, un suivi sur plusieurs années, des analyses acoustiques et des expériences de propagation et de diffusions passives et interactives, nous avons montré que i) les chants suivent des règles de construction syntaxique complexes et présentent des microdialectes, ii) les mâles voisins ont de nombreux chants en commun, discriminent les chant du groupe vs des chants inconnus, iii) les mâles portent une signature acoustique individuelle complexe et utilisent différentes stratégies d’interaction acoustique entre eux, iv) les groupes de voisins sont des communautés pérennes perpétuant des traditions vocales. / The Winter wren is a forest songbird singing discrete songs for territorial defense and mate attraction. Neighbouring males defending adjacent territories form acoustic communication networks. Little is known about such networks concerning their onset, dynamics and evolution in time, under natural conditions.By means of focal and continuous recordings, a survey over several years, acoustic analyses as well as propagation and playback experiments, we showed that: i) songs follow complex syntactical rules and form microdialects, ii) neighbouring males share many songs and discriminate between songs from neighbours and strangers, iii) males have complex individual acoustic signatures and use differential singing strategies in interaction with each other, iv) groups of neighbours are perennial communities maintaining vocal traditions.

Over the past century, populations of North American grassland songbirds have declined sharply as a consequence of habitat destruction. Alberta’s mixed-grass prairie constitutes Canada’s largest remaining tract of native grassland. However, this region has recently undergone a rapid expansion of conventional oil and natural gas development, and few studies have documented its effects on songbird nesting success. During the 2012-2014 breeding seasons, I monitored 813 nests of grassland songbirds located at sites that varied with respect to presence/absence, distance from, and types of oil and gas infrastructure (pump jacks, screw pumps, compressor stations) and gravel roads. Nest survival was significantly lower at infrastructure sites relative to controls for both Savannah sparrow and vesper sparrow. Additionally, vesper sparrow nest density was greater within 100 m of structures. These findings suggest that habitat disturbance caused by infrastructure may result in increased frequencies of nest predation at multiple spatial scales. / February 2016

Severe declines in the number of some songbirds over the last 40 years have caused heated debate amongst interested parties. Many factors have been suggested as possible causes for these declines, including an increase in the abundance and distribution of an avian predator, the Eurasian sparrowhawk Accipiter nisus. To test for evidence for a predator effect on the abundance of its prey, we analyse data on 10 species visiting garden bird feeding stations monitored by the British Trust for Ornithology in relation to the abundance of sparrowhawks. We apply Bayesian hierarchical models to data relating to averaged maximum weekly counts from a garden bird monitoring survey. These data are essentially continuous, bounded below by zero, but for many species show a marked spike at zero that many standard distributions would not be able to account for. We use the Tweedie distributions, which for certain areas of parameter space relate to continuous nonnegative distributions with a discrete probability mass at zero, and are hence able to deal with the shape of the empirical distributions of the data. The methods developed in this thesis begin by modelling single prey species independently with an avian predator as a covariate, using MCMC methods to explore parameter and model spaces. This model is then extended to a multiple-prey species model, testing for interactions between species as well as synchrony in their response to environmental factors and unobserved variation. Finally we use a relatively new methodological framework, namely the SPDE approach in the INLA framework, to fit a multi-species spatio-temporal model to the ecological data. The results from the analyses are consistent with the hypothesis that sparrowhawks are suppressing the numbers of some species of birds visiting garden feeding stations. Only the species most susceptible to sparrowhawk predation seem to be affected.

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