According to the "public information" hypothesis, some animal species may monitor the current reproductive success of conspecifics to assess local habitat quality and to choose their own subsequent breeding site. To test this hypothesis experimentally, we manipulated two components of public information, the mean number of offspring raised locally ("quantity") and their condition ("quality"), in the collared flycatcher Ficedula albicollis. Immigration rate decreased with local offspring quantity but did not depend on local offspring quality, suggesting that immigrants are deprived of information regarding local quality. Conversely, emigration rate increased both when local offspring quantity or quality decreased, suggesting that residents can use both components of public information.

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.

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Summary 1.Public information, i.e. local reproductive performance of conspecifics, is expected to be a highly valuable cue for breeding habitat selection. However, the access to this cue may be spatially and temporally constrained. When public information is unavailable, individuals may use other integrative cues, such as the local density of breeders. 2. Departure decisions of collared flycatchers ( Ficedula albicollis ) were shown previously to be related to both public information and breeding density, in a long-term correlative study of a fragmented population. Here, we tested whether flycatchers also use public information (number and condition of fledglings produced locally) and breeding density to make individual settlement decisions in the following year. 3. Immigration rates were computed to measure the degree of attractiveness of patches to new breeders. We investigated the relative influence of public information and breeding density on immigration rates of yearlings and older adults separately. The access to public information for settlement decisions may indeed be more limited for yearlings. 4. Immigration rate in a patch increased with mean fledgling number in the previous year for older adults but not for yearlings. Yearling immigration rate was correlated positively to mean fledgling condition when patch breeding density in the previous year was low, but negatively when density was high. 5. Immigration rates of both yearlings and older adults increased with breeding density in the previous year. Breeding density explained a larger part of the variance in immigration rate than patch reproductive success. 6. The proportion of yearlings among breeders decreased with increasing patch reproductive success and breeding density in the previous year, suggesting that local competition was high in attractive patches. 7. Our results thus suggest that public information is also used for immigration decisions. However, decisions of yearlings are more complex than those of older adults, due to their more limited access to public information and the higher impact of intraspecific competition. Conversely, all individuals seemed to cue on breeding density in a similar way. Density is correlated to patch reproductive success, and may be a more easily accessible cue. We discuss the potential advantages of using conspecific density over conspecific reproductive performance for future immigration decisions.

Major life history traits, such as fecundity and survival, have been consistently demonstrated to covary positively in nature, some individuals having more resources than others to allocate to all aspects of their life history. Yet, little is known about which resources (or state variables) may account for such covariation. Reactive oxygen species (ROS) are natural by-products of metabolism and, when ROS production exceeds antioxidant defenses, organisms are exposed to oxidative stress that can have deleterious effects on their fecundity and survival. Using a wild, long-lived bird, the Alpine Swift (Apus melba), we examined whether individual red cell resistance to oxidative stress covaried with fecundity and survival. We found that males that survived to the next breeding season tended to be more resistant to oxidative stress, and females with higher resistance to oxidative stress laid larger clutches. Furthermore, the eggs of females with low resistance to oxidative stress were less likely to hatch than those of females with high resistance to oxidative stress. By swapping entire clutches at clutch completion, we then demonstrated that hatching failure was related to the production of low-quality eggs by females with low resistance to oxidative stress, rather than to inadequate parental care during incubation. Although male and female resistance to oxidative stress covaried with age, the relationships among oxidative stress, survival, and fecundity occurred independently of chronological age. Overall, our study suggests that oxidative stress may play a significant role in shaping fecundity and survival in the wild. It further suggests that the nature of the covariation between resistance to oxidative stress and life history traits is sex specific, high resistance to oxidative stress covarying primarily with fecundity in females and with survival in males.

Summary 1.Many studies investigating fitness correlates of dispersal in vertebrates report dispersers to have lower fitness than philopatric individuals. However, if dispersers are more likely to produce dispersing young or are more likely to disperse again in the next year(s) than philopatric individuals, there is a risk that fitness estimates based on local adult survival and local recruitment will be underestimated for dispersers. 2. We review the available empirical evidence on parent-offspring resemblance and individual lifelong consistency in dispersal behaviour, and relate these studies to recent studies of fitness correlates of dispersal in vertebrates. 3. Of the 12 studies testing directly for parent-offspring resemblance in dispersal propensity, five report a significant resemblance. The average effect size ( r ) of parent-offspring resemblance in dispersal was 0·15 [95% confidence interval (CI) = 0·07-0·22], with no difference between the sexes (average weighted effect size of 0·12 (0·08-0·16) and 0·16 (0·11-0·20) for females and males, respectively). Only three studies report data on within-individual consistency in dispersal propensity, of which two suggest dispersers to be more likely to disperse again. 4. To assess the magnitude of fitness underestimation expected for dispersing individuals depending on the heritability of dispersal distance and study area size, we used a simulation approach. Even when study area size is 10 times the mean dispersal distance, local recruitment per breeding event may be underestimated by 4-10%, generating a potential difference of 4-60% in average lifetime production of recruits between dispersing and philopatric individuals, with larger differences in long-lived species. 5. Estimates of both fitness correlates of dispersal and parent-offspring resemblance or withinindividual consistency in dispersal behaviour have been reported for 11 species. Although some comparisons suggest genuine differences in fitness components between philopatric and dispersing individuals, others, based on adult and juvenile survival, are open to the alternative explanation of biased fitness estimates. 6. We list three potential ways of reducing the risk of making wrong inferences on biased fitness estimates due to such non-random dispersal behaviour between dispersing and philopatric individuals: (a) diagnosing effects of non-random dispersal, (b) reducing the effects of spatially limited study area and (c) performing controlled experiments.Key-words: dispersal behaviour, intrafamily resemblance, heritability and individual consistency, life-history traits, local apparent survival and recruitment rate, temporary or permanent emigration.

Summary1. Breeding habitat quality strongly aects ®tness. Therefore, individuals are likely to select their breeding habitat after gathering information on quality of potential breeding patches. In the study reported in this paper, we investigated whether local reproductive success of conspeci®cs in a patch (patch reproductive success, PRS) could be used to assess habitat quality and make dispersal decisions in a non colonial, hole-nesting, passerine bird, the collared¯ycatcher (Ficedula albicollis). 2. Assumptions for such a breeding habitat selection mechanism were met: the habitat patches were of dierent quality, as measured by PRS, with relative quality varying between years, and PRS was autocorrelated in time.3. As in many other species, breeding dispersal was related in both sexes to individual reproductive success before dispersal: unsuccessful individuals were more likely to disperse than successful ones. 4. Additively, PRS in¯uenced both breeding and natal dispersal. This eect depended on sex. Dispersal was negatively related to PRS in females, and positively in males with low competitive ability (juvenile and unsuccessful adult males). 5. Breeding dispersal was positively related to¯ycatcher density in males, but negatively in females. Moreover, when included in the analyses, laying date of the previous breeding attempt (which should be correlated with competitive ability) replaced the eect of PRS in adult males. 6. The observed patterns can be explained by PRS (or another variable correlated with PRS) being used to assess dierent components of habitat quality in each sex, in relation to intraspeci®c competition pressure. We suggest that males of low competitive ability may either use PRS to assess the level of expected intraspeci®c competition the following year, and choose to disperse from high PRS woodlands, or be forced to disperse when PRS is high because of strong competition. Females might use PRS to assess the expected reproductive output if breeding in the patch the following year.Key-words: conspeci®c cues, dispersal, habitat quality, environment predictability, spatial scale. (1999) Journal of Animal Ecology

Analysis of long-term monitoring data on breeding collared flycatchers (Ficedula albicollis Temm.) has revealed equal numbers of immigrations and emigrations between neighboring populations of different sizes. Dispersal patterns were close to patterns simulated under a conditional dispersal and with populations near saturation level. Local growth rates of the 11 sites were computed and did not support the idea that the observed balanced exchanges could be the result of a source-sink system. This is the first empirical evidence for a system of discrete habitat patches with component populations that exist as simultaneous sources and sinks to their neighbors. Dispersal propensities were inversely related to population sizes, which showed little variation in time. These results are consistent with recent modeling of dispersal as an evolutionarily stable strategy, and they demonstrate that dispersal can be an active phenomenon requiring neither the dominance hierarchies nor the temporal instability generally invoked by ecological and population genetic models. We note a parallel to the concept of Ideal Free Distributions and discuss implications for the evolution of dispersal mechanisms in fragmented populations.