Using FTA® cards to store avian blood samples for genetic studies. Their application in sex determination

FTA® cards were used for long‐term storage of avian blood samples. Blood DNA was extracted by a simple method and used in PCR for sex identification of adult and nestling Great Grey Shrikes Lanius excubitor.     

Patterns of host–parasite associations in tropical lice and their passerine hosts in Cameroon

Coevolutionary processes that drive the patterns of host–parasite associations can be deduced through congruence analysis of their phylogenies. Feather lice and their avian hosts have previously been used as typical model systems for congruence analysis; however, such analyses are strongly biased toward nonpasserine hosts in the temperate zone. Further, in the Afrotropical region especially, cospeciation studies of lice and birds are entirely missing. This work supplements knowledge of host–parasite associations in lice using cospeciation analysis of feather lice (genus Myrsidea and the Brueelia complex) and their avian hosts in the tropical rainforests of Cameroon. Our analysis revealed a limited number of cospeciation events in both parasite groups. The parasite–host associations in both louse groups were predominantly shaped by host switching. Despite a general dissimilarity in phylogeny for the parasites and hosts, we found significant congruence in host–parasite distance matrices, mainly driven by associations between Brueelia lice and passerine species of the Waxbill (Estrildidae) family, and Myrsidea lice and their Bulbul (Pycnonotidae) host species. As such, our study supports the importance of complex biotic interactions in tropical environments.     

Island and taxon effects in parasitism revisited: avian malaria in the Lesser Antilles

We identify and describe the distribution of 12 genetically distinct malaria parasite lineages over islands and hosts in four common passerine birds in the Lesser Antilles. Combined parasite prevalence demonstrates strong host effects, little or no island effect, and a significant host-times-island interaction, indicating independent outcomes of host-parasite infections among island populations of the same host species. Host- and/or island-specific parasite lineages do not explain these host-parasite associations; rather, individual lineages themselves demonstrate the same type of independent interactions. Unlike overall prevalence, individual parasite lineages show considerable geographic structure (i.e., island effects) as well as species effects indicating that parasite lineages are constrained in their ability to move between hosts and locations. Together, our results suggest an upper limit to the number of host individuals that malaria parasites, as a community, can infect. Within this limit, however, the relative frequency of the different lineages varies reflecting fine scale interactions between host and parasite populations. Patterns of host-parasite associations within this system suggest both historical co-evolution and ecologically dynamic and independent host-parasite interactions.     

Extra-pair paternity is not repeatable between years in Pied Flycatchers (Ficedula hypoleuca): a role for social context

Extra-pair paternity (EPP) is the consequence of the interactions between a social pair and extra-pair males during the female's fertile phase in a specific social context and ecological environment. Although EPP occurs in many avian species, there is a lack of understanding of how environmental factors may impact its frequency. Accordingly, the relative importance of individual characteristics on the one hand, and of their immediate social environment on the other, may affect EPP repeatability and thereby the capacity of this trait to respond to selection. If EPP is an individual genetically based trait that may respond to selection, we expect it to be repeatable across breeding seasons. To check this possibility, we analysed the within-individual repeatability in EPP of breeding males and females in two natural populations of Pied Flycatchers Ficedula hypoleuca in central Spain during three field seasons. We then studied the relationship between EPP and individual male and female traits (only some of which were themselves repeatable), as well as key context variables such as breeding synchrony and population density. Our results showed no repeatability for EPP in either sex. We found a positive association with laying date and stronger associations of EPP with male plumage and morphological traits than with female characteristics. We suggest that the variable social environment is an important modulator of EPP patterns, and that differences between field EPP studies in this respect may explain contradictory results in the same species, even in the same populations in different years.     

Nocturnal migrants do not incur higher collision risk at wind turbines than diurnally active species

Nocturnally migrating birds, particularly passerines, are known to be vulnerable to collision with man‐made structures such as buildings, towers or offshore platforms, yet information with respect to wind farms is ambiguous. We recorded bird flight intensities using radar during autumn migration at four wind farms situated within a major migration flyway in northern Germany and simultaneously conducted systematic searches for collision fatalities at the same sites. We found that migration traffic rates at rotor height estimated by radar observations were significantly higher during the night, yet strictly nocturnal migrants constituted only 8.6% of all fatalities at the wind farms. In contrast to the situation at other vertical structures, nocturnal migrants do not have a higher risk of collision with wind energy facilities than do diurnally active species, but rather appear to circumvent collision more effectively.     

Sex differences in circulating antibodies in nestling Pied Flycatchers Ficedula hypoleuca

Sex differences in immune function are relatively well studied in vertebrate animals, although the patterns are not always clear in birds. The study of immune responses in nestlings of wild bird populations may constitute an appropriate way to investigate inherent intersexual differences while controlling for environmental conditions such as parasitism that affect male and female individuals growing in the same nest. We studied whether the cell‐mediated immune response, as measured by phytohaemagglutinin (PHA) injection, and the levels of circulating antibodies differ between sexes of Pied Flycatcher nestlings Ficedula hypoleuca. No sex differences in nestling cell‐mediated immune response were found, but females showed significantly higher levels of plasma immunoglobulins than males did. Although nestling birds may not have a fully functional humoral immune defence, our study indicates that sex differences in the humoral component exist at this early stage of life. Given the importance of antibodies in the fight against parasite, bacterial and viral infections, the intrinsic sex disparity in circulating antibodies may have important implications for the life history of each sex.     

Passerine migration strategies and body mass variation along geographic sectors across East Africa, the Middle East and the Arabian Peninsula

Using the body mass estimates of 12 long-distance migrating Palearctic passerine species monitored at successive sites across the Eastern Africa flyway, we tested whether birds modulate their body mass according to specific seasonal demands across different geographic sectors. We compared body mass estimates across latitudinal distances and geographic sectors in Europe, the desert, Northeast Africa and East Africa. Our results show that, depending on the species and season considered, the average body mass increase or decrease is variable at and among different geographic sectors. By comparing the variation in body mass between different ecological sectors, we were able to show when and where migrants accumulate their migratory fuel reserves during migration.