For over 50 years, the great tit (Parus major) has been a model species for research in evolutionary, ecological and behavioural research; in particular, learning and cognition have been intensively studied. Here, to provide further insight into the molecular mechanisms behind these important traits, we de novo assemble a great tit reference genome and whole-genome re-sequence another 29 individuals from across Europe. We show an overrepresentation of genes related to neuronal functions, learning and cognition in regions under positive selection, as well as increased CpG methylation in these regions. In addition, great tit neuronal non-CpG methylation patterns are very similar to those observed in mammals, suggesting a universal role in neuronal epigenetic regulation which can affect learning-, memory- and experience-induced plasticity. The high-quality great tit genome assembly will play an instrumental role in furthering the integration of ecological, evolutionary, behavioural and genomic approaches in this model species.

2002. Post-fledging survival of individual great tits: the effect of hatching date and fledging mass. -Oikos 99: 481-488.Pre-breeeding survival is one of the major sources of individual variation in lifetime reproductive success. However, very little is known about the reasons for differences in survival among individuals during this important phase of the life cycle. Some studies, using local return rates as indices of survival, have shown a relationship between post-fledging survival and fledging date and mass in birds, most of them suggesting directional selection towards heavy masses and early fledging dates. Recent development of capture-recapture models allows the separate estimate of survival and recapture probabilities, as well as the inclusion of individual covariates into the modelling process. We used here these models to explore the relative effects of fledging date and fledging mass on local recruitment of individual great tit Parus major fledglings. Individual capture-recapture histories of 2051 fledglings (cohorts 1992-1999), 184 of which were recaptured as breeding birds during 1993-2000, were used in the analyses. Hatching date, offspring mass at day 15, their squared terms, and interactions between mass and date, were included as covariates into the modelling process. Models with age (fledglings and adults) and time (year) dependence were used. The probability of local recruitment increased with fledging mass in each of the years studied. Fledging date also affected recruitment but, against what is commonly thought, fledgling early is not the best option every year. Either early, intermediate or late fledglings were favoured in different years. This between-year variation in the optimum fledging date offers an alternative explanation to the lack of evolution towards earlier breeding dates, in spite of the advantages of early breeding some years.

No abstract

1. Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of lightlevel geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data.2. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially.

Summary 1.We studied age-specific survival rates in the willow tit Parus montanus in northern Finland using 15 years of capture-recapture data obtained from birds during the breeding seasons 1986-2000. In addition, short-and long-term costs of reproduction were investigated by comparing survival probabilities of breeding and non-breeding individuals. 2. We did not find evidence supporting age-specific survival probabilities in males. However, in females there was a significant decline in survival after the age of 5 years. 3. Reproduction did not impair individuals' chances of being alive in the subsequent year (short-term cost) because breeding males and females had similar survival rates as non-breeders. 4. Demographic costs of breeding appeared later in life. Females skipping breeding earlier in life showed a higher probability of survival after the age of 5 years than females that bred every year until that age. This effect was non-significant in males. 5. The observed decline in survival probability late in life is likely to result from an increased cost of reproduction due to higher allocation of resources to breeding earlier in life, i.e. increased effort early in life is traded with survival late in life. The results also suggest that income breeders, such as small passerines, may pay long-term costs of reproduction. This is in agreement with the disposable soma theory of ageing.