Environmental and Parental Influences on Offspring Health and Growth in Great Tits (Parus major)

PMCID: PMC3728352This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Blood parasites found in three passerine species during spring migration

Blood samples from three common passerine bird species, Robin, Redstart and Lesser Whitethroat, were collected during spring migration in the south-western archipelago of Finland. A total of 10 parasitic haemosporidian and trypanosomid species were recorded. The proportion of parasited samples of all three bird species was 18 .0%, with no significant differences between them. Furthermore, the prevalence of parasites did not differ between the sexes in Redstarts and between age classes in Robins and Lesser Whitethroats . Instead, species that belong to the same family (Turdidae: Redstart and Robin) were partly infected with the same parasite species. The Lesser Whitethroat, belonging to the family Sylviidae, was infected with different blood parasite species compared with the Turdids. Our results indicate that during migration, the prevalence of blood parasites is rather low and that the taxonomic relationships of bird species is related to their parasitic fauna

An analysis of continent-wide patterns of sexual selection in a Passerine bird

Patterns of selection are widely believed to differ geographically, causing adaptation to local environmental conditions. However, few studies have investigated patterns of phenotypic selection across large spatial scales. We quantified the intensity of selection on morphology in a monogamous passerine bird, the barn swallow Hirundo rustica, using 6495 adults from 22 populations distributed across Europe and North Africa. According to the classical Darwin-Fisher mechanism of sexual selection in monogamous species, two important components of fitness due to sexual selection are the advantages that the most attractive males acquire by starting to breed early and their high annual fecundity. We estimated directional selection differentials on tail length (a secondary sexual character) and directional selection gradients after controlling for correlated selection on wing length and tarsus length with respect to these two fitness components. Phenotype and fitness components differed significantly among populations for which estimates were available for more than a single year. Likewise, selection differentials and selection gradients differed significantly among populations for tail length, but not for the other two characters. Sexual selection differentials differed significantly from zero across populations for tail length, particularly in males. Controlling statistically for the effects of age reduced the intensity of selection by 60 to 81%, although corrected and uncorrected estimates were strongly positively correlated. Selection differentials and gradients for tail length were positively correlated between the sexes among populations for selection acting on breeding date, but not for fecundity selection. The intensity of selection with respect to breeding date and fecundity were significantly correlated for tail length across populations. Sexual size dimorphism in tail length was significantly correlated with selection differentials with respect to breeding date for tail length in male barn swallows across populations. These findings suggest that patterns of sexual selection are consistent across large geographical scales, but also that they vary among populations. In addition, geographical patterns of phenotypic selection predict current patterns of phenotypic variation among populations, suggesting that consistent patterns of selection have been present for considerable amounts of time