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.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Animal Ecology. Summary 1. The hypothesis that late breeding entails reproductive costs to birds was tested by comparing breeding traits of control and delayed great tit Parus major clutches. 2. In our study area, great tits and house sparrows Passer domesticus compete for nesting boxes. Since early March, nesting boxes were checked twice a week and initiated sparrow nests removed, to allow great tits to breed. 'Delayed' great tit pairs were those which, having a territory, had the nesting where they eventually bred occupied by sparrows, and therefore did not start laying until these abandoned the nesting box. Delayed pairs were assumed to be a random sample of the population. Age composition (1-year vs. older birds) and tarsus length did not differ between control and delayed birds. 3. In 1990-92, a total of 40 pairs had their breeding delayed, while 56 acted as controls. The mean laying date of delayed pairs was at least 10 days later than controls. 4. Delayed first clutches were smaller and took longer to hatch than controls, but mean egg volume did not differ between them. Fledging success was lower in delayed nests. Young from delayed broods were lighter at day 15 and reached a lower asymptotic weight. The mean growth rate of the nestlings was negatively related to clutch size, and differed between years, but did not differ between control and delayed broods. 5. Control pairs were more likely to produce a second clutch, if the first one succeeded, or a replacement clutch, if the first one failed, than delayed pairs. The total production of fledglings per pair per season was higher in control pairs. Control pairs were more likely to recruit at least one young into the local breeding population than delayed pairs. However, it is not known whether late fledglings dispersed further. 6. Our results show that delayed pairs produced fewer fledglings, of lower quality, and were less likely to recruit them into the local breeding population than controls. Therefore, the causal relationship between poor breeding performance and late breeding is supported.

Habitat fragmentation is one of the most important threats to biodiversity in the last decades. Numerous species are forced to adapt to human presence as urbanization keeps increasing. Some studies show the impact of habitat changes in various species; however, there is little knowledge about the effect of habitat disturbance on hedgehogs in the Iberian Peninsula. We radio tracked 31 male hedgehogs: 14 European hedgehogs and 17 Algerian hedgehogs, being 18 individuals indigenous and 13 translocated. We analysed their home ranges, spatial behaviour and habitat use in a suburban area of Valencia City, Spain, where the two species coexist. Our results show that there are phenologic variations of activity levels, which differ between species, being maximum in spring for the European hedgehog and in summer for the Algerian hedgehog. We did not detect a territorial behaviour or interspecific spatial competition. However, we could detect a clear “release effect”, with translocated individuals presenting increased home range sizes and activity levels as they explore the unknown environment. Furthermore, we found that both species showed a clear preference for the pine forest habitat, avoiding all other habitat types, especially those with high human presence. Our results also suggest that the European hedgehog has a more generalist character than the Algerian hedgehog regarding habitat use. In conclusion, this study highlights the importance of conserving a connected mosaic of green patches in urbanized environments for the conservation of hedgehog populations.

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Habitat and weather conditions effects on long-term breeding population dynamics of five species of herons (Ardeidae) and Glossy ibis (Threskiornithidae) in the Valencian Community, SpainValencian wetlands include 65 % of the region's priority habitats and most are protected areas. Waterfowl populations are used as indicators of the state of these environments. We calculated the linear population trend by species, per wetland, of five Ardeidae and Plegadis falcinellus (Threskiornitidae) species using data from the annual census between 1984-2015 for 11 selected wetlands. We constructed a matrix with 42 habitat and meteorological variables, and evaluated the relation between these variables and population trends by a Correspondence Analysis. We found an increasing trend for most species. The populations of the L'Albufera de Vàlencia Natural Park (NP) differed significantly from the rest. Ardea cinerea, E. garzetta, B. ibis and A. ralloides would be associated with large areas, and also with swamps and rice fields, while A. purpurea and P. falcinellus would be related to environments characterised by rainfall and the level of protection in the area. Rice fields and water management have been important for establishing breeding colonies.