Abstract: Several vertebrates choose their mate according to genetic heterozygosity and relatedness, and use odour cues to assess their conspecifics' genetic make-up. In birds, although several species (including the black-legged kittiwake) exhibit non-random mating according to genetic traits, the cues used to assess genetic characteristics remain unknown. The importance of olfaction in birds' social behaviour is gaining attention among researchers, and it has been suggested that, as in other vertebrates, bird body scent may convey information about genetic traits. Here, we combined gas chromatography data and genetic analyses at microsatellite loci to test whether semiochemical messages in preen secretion of kittiwakes carried information about genetic heterozygosity and relatedness. Semiochemical profile was correlated with heterozygosity in males and females, while semiochemical distance was correlated with genetic distance only in malemale dyads. Our study is the first to demonstrate a link between odour and genetics in birds, which sets the stage for the existence of sophisticated odour-based mechanisms of mate choice also in birds.

Abstract: Foraging skills of young individuals are assumed to be inferior to those of adults. The reduced efficiency of naive individuals may be the primary cause of the high juvenile mortality and explain the deferment of maturity in long-lived species. However, the study of juvenile and immature foraging behaviour has been limited so far. We used satellite telemetry to compare the foraging movements of juveniles, immatures and breeding adult wandering albatrosses Diomedea exulans, a species where foraging success is positively influenced by the distance covered daily. We showed that juveniles are able to use favourable winds as soon as the first month of independence, but cover shorter distances daily and spend more time sitting on water than adults during the first two months after fledging. These reduced movement capacities do not seem to be the cause of higher juvenile mortality. Moreover, juveniles almost never restrict their movement to specific areas, as adults and immatures frequently do over shelf edges or oceanic zones, which suggest that the location of appropriate areas is learned through experience. Immatures and adults have equivalent movement capacities, but when they are central place foragers, i.e. when adults breed or immatures come to the colony to display and pair, immatures make shorter trips than adults. The long duration of immaturity in this species seems to be related to a long period of learning to integrate the foraging constraints associated with reproduction and central place foraging. Our results indicate that foraging behaviour of young albatrosses is partly innate and partly learned progressively over immaturity. The first months of learning appear critical in terms of survival, whereas the long period of immaturity is necessary for young birds to attain the skills necessary for efficient breeding without fitness costs.

Abstract: Variability in demographic traits between individuals within populations has profound implications for both evolutionary processes and population dynamics. Parental effects as a source of non-genetic inheritance are important processes to consider to understand the causes of individual variation. In iteroparous species, parental age is known to influence strongly reproductive success and offspring quality, but consequences on an offspring fitness component after independence are much less studied. Based on 37 years longitudinal monitoring of a long-lived seabird, the wandering albatross, we investigate delayed effects of parental age on offspring fitness components. We provide evidence that parental age influences offspring performance beyond the age of independence. By distinguishing maternal and paternal age effects, we demonstrate that paternal age, but not maternal age, impacts negatively post-fledging offspring performance.

Abstract: This paper compares chemical stratigraphies from snowpits collected at Dome C (East Antarctica) in order to assess site variability in terms of spatial distribution of chemical markers, annual accumulation rate and chemical species persistence in the snow layers. Since Dome C was chosen for deep drilling down to the bedrock in the framework of EPICA (European Project for Ice Coring in Antarctica), to provide 800kyr of climatic and environmental records, evaluating site variability is fundamental for a reliable interpretation of the deep ice core stratigraphies.
For this purpose, 4 snowpits were dug at Dome C (1997/98, 1998/99, 2000/01 and 2005/06 Antarctic Campaigns) and analysed for cations, inorganic anions and methane sulphonate by ion chromatography. Unlike the first three snowpits, the most recent one was analysed directly in situ, allowing to observe that no chemical contamination or loss due to sample storage and transport to Europe occurs for such a sampling.
Accumulation rate variability was revealed to be around 4% in a common time range (1992-1964) for all snowpits. Intra-snowpit chemical variability was definitely higher than inter-snowpit variability, indicating that the variations observed in the chemical stratigraphies from Dome C can be reliably related to effective changes in source and transport mechanisms of the investigated markers more than to site variability.
Post-depositional phenomena affecting chloride, nitrate and methane sulphonate were studied, revealing a logarithmic decay as a function of depth for Cl- and MSA and an exponential one for NO3-. The relative losses were quantified in the 75-80% range for Cl-, 66-83% for MSA and 89-94% for NO3- and were found to stop around 320, 320 and 60-80cm depth, respectively.