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A timeline for the urbanization of wild birds: The case of the lesser kestrel

The Lesser kestrel (Falco naumanni) evolved as a separate species in the Old-World kestrel radiation starting in the late Miocene. Given that the first cities were erected in the Holocene, this urban colonial raptor has only become a major town dweller recently in its evolutionary history. Today, more than 95% of lesser kestrel colonies in Spain and other Mediterranean countries are on buildings, and the remaining few are on rocky outcrops, that may have been the original nesting substrate for this cavity-nesting bird. Lesser kestrel fossils are well represented in cave sites, and their paleontological distribution, spanning from the Early Paleolithic to the Epipaleolithic, agrees well with its current breeding distribution. According to classical sources, such as the works of Columella and Pliny the Elder, and the presence of a skeletal remain in a Roman villa near Madrid, lesser kestrels may have nested in buildings and in urban settings for at least 2000e2500 years. However, there are no surviving colonies in structures older than 1400 years in Andalusia, nor in Spain. For a sample of 349 colonies on ancient buildings, a majority of the structures had been erected between the 15th and 17th centuries, this putting a time limit of about 300-600 years to the existence of those seemingly immemorial colonies. For specific towns and buildings, written references for the presence of lesser kestrel colonies do not go back more than two centuries. In fact, the Cathedral of Sevilla may be the structure with the longest continuous occupation by lesser kestrels recorded up to present time, from 1834 to 2020. Lesser kestrels were possibly too common in human settlements in the past as to be noted as special. This may explain the scarcity of references to the species until the 19th century. In any case, the same lack of information affects the other major Eurasian urban birds, as no timeline exist for the urbanization process of any other bird species. Here authors propose that lesser kestrels became urban breeders when both adequate cavities in buildings and cereal fields, where they capture their invertebrate prey, became available in their breeding range, several millennia ago. However, urban colonies, in contrast with the ones on stable geological substrates, have been forced to move from building to building when older ones became ruinous or were rebuilt, but new structures with suitable cavities became available throughout History. informacion[at]ebd.csic.es: Negro et al (2020) A timeline for the urbanization of wild birds: The case of the lesser kestrel. Quaternary Sci Rev https://doi.org/10.1016/j.quascirev.2020.106638


https://www.sciencedirect.com/science/article/pii/S0277379120306004?via%3Dihub
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The structure of waterbird seed dispersal networks is not mediated by functional traits

The structure of waterbird seed dispersal networks is not mediated by functional traits

Plants and their dispersers form interaction networks whose structure has important implications for the persistence and stability of the community. Frugivory is vital for the dispersal of many plants, but the dispersal interactions between plants and non-frugivorous animals, such as waterfowl, are poorly studied. In this study, the authors characterized the structure of networks for seed dispersal by waterfowl, considered whether their structure is similar to that of the networks formed between frugivorous birds and plants with fleshy fruits, and searched for functional traits of birds or plants that are important for maintenance of network structure. Data from four European community-level studies on the content of the digestive tracts of ducks and rallids, including 12 species of birds and 88 of plants, were used. Waterbird seed dispersal networks shared some organizational patterns with those of frugivores, but unlike frugivores, their underlying structure was not related to functional traits. This is likely related to fundamental differences between waterfowl and frugivores in the way they ingest seeds. Differences in the functional role of particular waterbird species for seed dispersal are likely due to other processes, such as differences in population size, movement patterns, microhabitat selection, or gut processing of seeds. informacion[at]ebd.csic.es: Sebastián-González et al (2020) Waterbird seed-dispersal networks are similarly nested but less modular than those of frugivorous species, and not driven by species ecological traits. Funct Ecol https://doi.org/10.1111/1365-2435.13657


https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.13657