P. 2005. Differential migration of chiffchaffs Phylloscopus collybita and P. ibericus in Europe and Africa. Á/ J. Avian Biol. 36: 184 Á/190.Differential migration is a widespread, but poorly understood, phenomenon in birds. In this paper, we present the first detailed field study of differential migration in the Old World warbler (Sylviidae) family. We studied two chiffchaff Phylloscopus [collybita ] semispecies: the common chiffchaff P. [c. ] collybita and the Iberian chiffchaff P. [c. ] ibericus. Using data collected at several latitudes in Europe and Africa, we present convincing evidence for differential distance migration of sexes in chiffchaffs, with females moving further than males. Interestingly, while there was a pronounced gradient in the sex-ratios in Europe and North Africa (with an increasing proportion of females with declining latitude), no clear pattern was found south of the Sahara, where sex-ratios were more male-biased than predicted by a simple latitude model. This suggests that, amongst the chiffchaffs wintering in West Africa, a large proportion is composed by Iberian birds, and provides support to previous suggestions that Iberian chiffchaffs are long distance migrants. Results from detailed studies in Senegal also show that chiffchaffs display differential timing of spring migration, with males leaving the winter quarters considerably earlier than females. The results are discussed in the framework of the three main (non-mutually exclusive) hypotheses attempting to explain the latitudinal segregation of the sexes. Given the relative failure of standard comparative studies to discriminate between competing single-factor hypotheses to explain differential migration, it is argued that the chiffchaff species complex might be particularly suited to study this issue using a new approach suggested by Cristol et al. (1999): detailed (further) comparisons between closely related species (such as the common and the Iberian chiffchaffs) could help identifying the key factors to be incorporated into optimality models that can predict relative distance of migration of different sex or age classes.

Fruits and seeds are critical food sources for many European passerines during the autumn migration, which in turn contribute to disperse seeds either internally, i.e. after ingestion (endozoochory), or externally, when seeds adhere to the body surface (epizoochory). Despite the recognized importance of birds as seed dispersers, the vast majority of studies focused on endozoochory while the external transport of seeds is frequently invoked as being potentially important, but remains largely unexplored. Th is is particularly important during the post-breeding migration of passerines, the most ubiquitous and diverse movement of potential seed carriers across Europe and into Africa, which coincides with the fruiting peak of many plant species (August -October). Our aim was to evaluate the role of migrating birds as potential long-distance seed dispersers, and comparing the prevalence of epizoochory and endozoochory during post-breeding migration. We sampled 926 wild birds in nine locations in Portugal, and retrieved 1833 seeds of 19 plant species dispersed internally and only three seeds externally attached to three birds ( Serinus serinus , Locustella naevia and Turdus merula ), showing an endozoochory prevalence 85 times higher than that of epizoochory. Migrating and non-migrating passerines dispersed seeds equally. While two of the seeds transported externally had specifi c adaptations to epizoochory, namely spines ( Torilis arvensis ) and hooks ( Galium aparine ), the third is a large seed from a fl eshy-fruited plant, Frangula alnus (i.e. typical endozoochorous syndrome). Th ese seeds were found on bird species with diff erent diets, but similar behaviour (ground foragers) and in similar habitats (open agro-ecosystems). Our results highlight the strong role of migrating passerines as potentially longdistance seed dispersers and show that, at least in the autumn, the prevalence of epizoochory is several orders of magnitude lower than that of endozoochory.

The conflict resulting from the expansion of human activities into natural habitats affects the structure and functioning of ecosystems. Similarly, the anthropogenic redistribution of many species all over the world affects the composition of biological communities, possibly altering their capacity to sustain key ecological functions, such as seed dispersal. Urban parks are extreme examples of such novel ecosystems resulting from the anthropogenic redistribution of species in a new ecological framework. Here, we describe the avian seed dispersal network in an urban recreational woodland in central Portugal (c.79 ha). Four quantitative seed dispersal networks were assembled by identifying intact seeds in the droppings of mist-netted birds throughout the year. Overall, 1,244 seeds were identified, representing 33 links between 15 plant species and 11 bird species. Most birds dispersed alien seeds, but these represented a small proportion of the overall network (20 % of the seeds and 13 % of the droppings). Blackcap (Sylvia atricapilla) was the main disperser of native and alien seeds in all seasons, particularly those of the invasive Phytolacca americana. Fleshy fruits were more abundant in summer, but were more consumed in winter, presumably when other foods were difficult to find. Our study suggests that even in a highly managed urban park, seed dispersal networks can be temporally complex and variable and that a network approach can be an important monitoring tool to detect the status of crucial ecosystem functions in rapidly changing habitats such as urban parks. Keywords Birds Á Ecosystem services Á Frugivory Á Novel ecosystems Á Urban parks Á Sylvia atricapilla Communicated by A. Weiskittel.

Aim All species are imbedded in a network of interactions with other species, which define an important component of their ecological niche. These interactions are dynamic and can change the emergence of vacant niches in the environment. Niche adjustments have been predicted to be particularly common on insular communities as a response to the poor and disharmonic biota of oceanic island -the interaction release hypothesis, however, the phenomena has not yet been reported on continents. Taxonomic groups of specialized nectarivorous birds are present on all continents except in Europe where they became extinct in the Oligocene, likely leaving behind underexplored flower resources. We performed the first community-level assessment of flower visitation by European birds to evaluate if insectivorous and granivorous birds show an interaction release towards consuming flower resources in Europe.Location Larc ßã -Coimbra, Portugal, Europe.Methods During one year, we collected pollen loads from the forehead of 634 birds. Pollen loads were prepared by acetolysis and all pollen grains were identified under a microscope. All interactions were compiled into a quantitative interaction matrix describing the first pollen-transport network by European birds.Results One-fifth of the bird individuals, corresponding to two thirds of the bird species sampled carried pollen from 45 different types. The vast majority of the plant species found were native but the alien Eucalyptus globulus was by far the species most commonly found in the birds' pollen loads. Overall, the structure of the pollen-transport network from Europe shared many attributes of other networks that include taxonomic groups of specialized nectarivorous birds.Main conclusions We show that the interaction release hypothesis is not exclusive to insular communities but can also be observed in continents, greatly increasing the potential geographical distribution of this phenomenon. However, it seems considerably less pronounced in Europe than in the Gal apagos, where it was first described, probably due to the much stronger selective pressures on the simplified ecosystems of oceanic islands.

Borrelia turdi is a spirochete from the Borrelia burgdorferi complex, first reported in Japan, that has been increasingly detected in Europe. This genospecies is mostly associated with avian hosts and their ornithophilic ticks such as Ixodes frontalis. In this study, we isolated B. turdi from five I. frontalis feeding on Turdus merula, Turdus philomelos, Parus major and Troglodytes troglodytes, and one Ixodes ricinus feeding on a T. merula in Portugal. These isolates were genetically characterised according to their 5S-23S rRNA intergenic spacer, 16S rRNA and through typing of seven housekeeping genes (multilocus sequence typing). Multilocus sequence analyses revealed that the strains isolated in our study, although belonging to B. turdi genospecies, are not identical to the B. turdi reference strain Ya501. Instead, our strains are separated into a clear defined group, suggesting that the European samples diverged genetically from the strain originally detected in Japan. Population analysis of 5S-23S rRNA sequences can further resolve subpopulations within B. turdi, but more samples from a large geographical scale and host range would be needed to assess potential phylogeographical patterns within this genospecies.

Birds are important biotic dispersers of a wide range of propagules. Fungi spores are mainly dispersed by wind. Nevertheless there are several animals known to disperse fungi spores, which might be particularly important if spores are delivered to particularly favourable sites i.e. directed dispersal. This may be especially important for fungi that require specific microsites such as flowers. We sampled birds for the presence of fungi spores and pollen grains during one year at two forest sites in central Portugal. We found that out of the 894 birds sampled, 131 individuals from 11 species carried spores from at least 6 morphological types, mainly during winter. The great majority of birds found to carry fungi spores was also found to carry pollen grains, suggesting that they were feeding on flowers which are the main origin of the spores. This co-dispersion of pollen and fungi spores suggest that the latter are not randomly dispersed on the environment, but are likely to have an increased probability of being deposited on flowers propitious to fungi development. Our results suggest that directed dispersal of fungi by flower-visiting birds might by a common and under-appreciated phenomenon with potentially important ecological, biogeographic and even economic outcomes.

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