Suchergebnisse

Bird winter-feeding has become a popular backyard activity around the world, particu-larly in northern regions of Europe and America with cold winters. However, the short- and long-term ecological consequences of such artificial feeding remain inconclusive. In seasonal environments, timing of breeding is a crucial aspect that can strongly influ-ence reproductive output and ultimately fitness. Individual condition at the start of the breeding season is especially important in determining breeding success, by influ-encing the onset of and investment in breeding. However, empirical evidence on the effects of winter feeding on avian breeding performance remain equivocal.We studied onset of reproduction (laying date) and breeding investment (clutch size) over seven consecutive seasons in a population of wild great tits Parus major in southern Sweden. During the first three years of study, no experimental manipulation was undertaken, while over the last four years the study area was exposed to either supplemented or unmanipulated winter feeding conditions. Breeding was positively affected by supplementary feeding during winter, as birds breeding in the supplemented area increased their clutch size compared to birds from the control area, although lay-ing date remained unaffected by winter feeding. Since differences in clutch size were absent during the three years prior to the experimental manipulation, the results sug-gest that winter supplementary feeding, and not inherent differences between the two areas, was the reason for the observed effect. Both breeding parameters varied over the years of study, although the effects of the experimental manipulation on clutch size remained consistent, which suggests a carry-over effect of winter feeding on subse-quent breeding performance. ; JB has been funded by the Andalucía Talent Hub Program launched by the Andalusian Knowledge Agency, co-funded by the European Union's Seventh Framework Program, Marie Skłodowska-Curie actions (COFUND – Grant Agreement no. 291780) and the ...

Basal metabolic rate (BMR) constitutes the lowest metabolic rate in a resting animal and is, therefore, considered to reflect the energetic cost of maintenance in endotherms. BMR is a reversible plastic trait that changes with environmental and ecological circumstances, albeit being heritable and susceptible to selection. Inter-individual variation within populations of small birds is substantial, and while many of the drivers of such variation have been identified, many remain unexplained. We studied winter BMR variation of juveniles over a 15-year period in a wild population of great tits Parus major at the northern border of their distribution. BMR during winter consistently changed between years, even after controlling for environmental factors, suggestive of a non-reversible developmental plasticity shaping the adult metabolic phenotype. BMR in cohorts of wintering great tits varied among winters as a response to minimum ambient temperatures experienced early in life, during the prehatching period. This developmental plasticity might be adaptive if temperatures experienced by growing embryos would metabolically prime them to an environment that they will likely encounter in future life. However, in line with a more unpredictable future climate, the risk of phenotype-environment mismatch is likely to lead to certain cohorts being poorly adapted to prevailing winter conditions, resulting in wider annual fluctuations in population size. ; Open access funding provided by Lund University. JB has been funded by the Andalucía Talent Hub Program launched by the Andalusian Knowledge Agency, co-funded by the European Union's Seventh Framework Program, Marie Skłodowska-Curie actions (COFUND—Grant Agreement no 291780) and the Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía. Supported by the Academy of Finland projects no. 102286 and 47195, and the Thule Institute of the University of Oulu (JB and EH) and by grants from the Swedish Research Council no. S-AA/F0 09677-311, B 650-19981108/2000, 629-2002-1893 and 621-2003-2912 (JÅN). ; Peer reviewed

Levels of exposure to pesticides in rice fields can be significant depending on the environmental policies practiced. The aim of European Union integrated management policy is to reduce pesticide use and impact on environment. Rice fields provide an alternative breeding habitat for many waterbirds that are exposed to the pesticides used and therefore can be valuable indicators of their risk for wildlife. To evaluate integrated management success we examined exposure of Black-winged Stilts (Himantopus himantopus) to cholinesterase-inhibiting pesticides in rice fields under different types of management by measuring plasma cholinesterase activity. Cholinesterase activity was lower in birds sampled in (a) 2008 after a period of intense pesticide application, than in (b) 2005-2007 and 2011 in rice fields subject to integrated management in Doñana (SW Spain) and (c) in control natural wetlands in Spain and Morocco. During 2009 and 2010, cholinesterase activity was lower in rice fields in Doñana than in rice fields in Larache and Sidi Allal Tazi (NW Morocco). Our results suggest that integrated management successfully reduced the exposure of Black-winged Stilts to pesticides in most of the years. Care should be taken to implement mosquito and pest crop controls on time and with environmentally friendly products in order to reduce its impact on wildlife. ; The Junta de Andalucía funded this study through the project "Las aves acuáticas de Doñana y el cultivo del arroz: la interacción entre la agricultura y la conservación de las zonas húmedas". This study was possible thanks to the INRA administration and CNRST-CSIC collaboration program (P2007MA01 and P2009MA01). GMT was funded by an I3P-CSIC grant for the formation of Researchers. MMH is supported by a Marie Curie Intra-European Fellowship for Career Development (PIEF-GA-2011-299747) within the 7th Framework Programme (FP7 2007-2013) of the European Commission. ; Peer Reviewed