Habitat selection by Black kite breeders and floaters: Implications for conservation management of raptor floaters

Preserving large predators is important but challenging because these species are typically wide-ranging, select multiple habitats at different scales and often present spatial or habitat separation between the breeder and floater sectors of a population. In addition, most of our knowledge on raptor floaters' habitat requirements comes from large solitary species, whose floaters often occupy temporary settlement areas spatially separate from breeding locations. Here, we examine space and habitat use by a loosely colonial, wetland-dependent raptor, the Black kite (Milvus migrans), in a population where floaters co-exist with territory holders, enabling a direct comparison of their habitat preferences. The study was conducted in Doñana National Park (South-Western Spain), a seasonally drying marshland currently surrounded by intensive agriculture and rice-fields. Intensive radio-tracking revealed that breeders and floaters selected and avoided the same habitats despite a radical, four-to-eight fold difference in their home-range dimensions: all kites over-selected open habitats suitable for their aerial foraging modes and avoided woodland and farmland. These results suggest a continuum of raptor population structures ranging from solitary species whose floaters select different habitats than breeders and are concentrated in spatially separate settlement areas, to colonial and semi-social species whose floaters fully coexist with breeders with shared habitat preferences. Both extremes of this continuum will pose challenges for conservation management. In solitary species, special conservation efforts may be required to identify and manage temporary settlement areas, while in gregarious species, the larger ranges of floaters may expose them to different threats than breeders, whose occurrence and consequences may be subtle to identify. © 2013 Elsevier Ltd.Peer Reviewe

Hardship at birth alters the impact of climate change on a long-lived predator

Climate change is increasing the frequency of extreme events, such as droughts or hurricanes, with substantial impacts on human and wildlife communities. Extreme events can affect individuals through two pathways: by altering the fitness of adults encountering a current extreme, and by affecting the development of individuals born during a natal extreme, a largely overlooked process. Here, we show that the impact of natal drought on an avian predator overrode the effect of current drought for decades, so that individuals born during drought were disadvantaged throughout life. Incorporation of natal effects caused a 40% decline in forecasted population size and a 21% shortening of time to extinction. These results imply that climate change may erode populations more quickly and severely than currently appreciated, suggesting the urgency to incorporate "penalties" for natal legacies in the analytical toolkit of impact forecasts. Similar double impacts may apply to other drivers of global change.</p

Floater interference reflects territory quality in the Spanish imperial eagle Aquila adalberti: a test of a density-dependent mechanism

We report on an 11–year study of floater interference in a population of Spanish Imperial Eagles Aquila adalberti. We analyzed changes over the years in the productivity of 15 territories to test predictions of two hypotheses of density-dependent productivity in relation to the presence of floaters (birds without territories). According to the ‘interference’ hypothesis, the frequency of intrusion by floaters increases with density, resulting in a decrease in productivity. Thus, in a high-density population a negative relationship between floater intrusions and productivity of the territory is expected. In contrast, under the ‘habitat heterogeneity’ hypothesis, as density increases a higher proportion of individuals is forced to occupy lower quality habitats. Support of this hypothesis requires that floaters detect differences in quality among territories and preferentially visit the better quality territories. Consequently, a positive relationship between floater intrusions and productivity is expected. Results showed that floaters tended to visit their natal area at the beginning of the breeding season. Among floater eagles, males made significantly more intrusions per day than did females, but females stayed in the natal population for longer each year than males. Floater intrusions and productivity were highly positively correlated, supporting the ‘habitat heterogeneity’ hypothesis; individuals were apparently able to assess the quality of a territory and, at the frequencies observed, their interference with the breeding pair had no obvious negative effect on productivity

Habitat selection by an avian top predator in the tropical megacity of Delhi: human activities and socio-religious practices as prey-facilitating tools

Research in urban ecology is growing rapidly in response to the exponential growth of the urban environment. However, few studies have focused on tropical megacities, and on the interplay between predators’ habitat selection and human socio-economic aspects, which may mediate their resilience and coexistence with humans. We examined mechanisms of breeding habitat selection by a synanthropic raptor, the Black Kite Milvus migrans, in Delhi (India) where kites mainly subsist on: (1) human refuse and its associated prey-fauna, and (2) ritualised feeding of kites, particularly practised by Muslims. We used mixed effects models to test the effect of urban habitat configuration and human practices on habitat selection, site occupancy and breeding success. Kite habitat decisions, territory occupancy and breeding success were tightly enmeshed with human activities: kites preferred areas with high human density, poor waste management and a road configuration that facilitated better access to resources provided by humans, in particular to Muslim colonies that provided ritual subsidies. Furthermore, kites bred at ‘clean’ sites with less human refuse only when close to Muslim colonies, suggesting that the proximity to ritual-feeding sites modulated the suitability of other habitats. Rather than a nuisance to avoid, as previously portrayed, humans were a keenly-targeted foraging resource, which tied a predator’s distribution to human activities, politics, history, socio-economics and urban planning at multiple spatio-temporal scales. Many synurbic species may exploit humans in more subtle and direct ways than was previously assumed, but uncovering them will require greater integration of human socio-cultural estimates in urban ecological research

Uso dello spazio, selezione d' habitat e rotte migratorie del Nibbio bruno (Milvus migrans): uno studio con telemetria convenzionale e satellitare (2010)

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Reproductive endocrinology of wild, long-lived raptors,

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Performance evaluation of congestion control for CoAP in 6TiSCH networks

The Internet of Things (IoT) is making changes in everyday life. The same is happening in the world of industry, where sensor networks monitor industrial processes. These networks are composed of devices with limited computational capacity, memory and autonomy. In the Industrial Internet of Things (IIoT) reliability and low latency are required, to meet these requirements the 6TiSCH architecture has been defined by IETF (Internet Engineering Task Force). In this work we evaluate the performance of Constrained Application Protocol (CoAP) over 6TiSCH networks with default congestion control policy, specifically we assess the performance and the challenges that comes from the adoption of CoAP congestion control when employing with IEEE 802.15.4 Time Slotted Channel Hopping (TSCH) MAC Protocol. This protocol guarantees low latency and high reliability. The communication resources in 6TiSCH networks are managed by Scheduling Functions (SFs), the nodes manage the communication schedule in a distributed manner with Distributed SF in the 6TiSCH schedule, that continuously monitor the traffic to allocate resources. The results show that there is a problem with the way distributed SFs are conceived, the tested system had performance limitations due to a lack of slots dedicated to communication between nodes. Changes have been made to the SF, adding dedicated downward slots. The results show that with this modification there is an increase in performance. The changes have been implemented in Contiki-NG, and simulations have been performed on the Cooja network simulator

Simultaneous analysis of multiple PCR amplicons enhances capillary SSCP discrimination of MHC alleles

Major histocompatibility complex (MHC) genotyping still remains one of the most challenging issues for evolutionary ecologists. To date, none of the proposed methods have proven to be perfect, and all provide both important pros and cons. Although denaturing capillary electrophoresis has become a popular alternative, allele identification commonly relies upon conformational polymorphisms of two single-stranded DNA molecules at the most. Using the MHC class II (β chain, exon 2) of the black kite (Aves: Accipitridae) as our model system, we show that the simultaneous analysis of overlapping PCR amplicons from the same target region subshttps://digital.csic.es/listadoMetadatos.jsp?ID=autores&vocabulary=autores&plataforma=pasarelatantially enhances allele discrimination. To cover this aim, we designed a multiplex PCR capable to generate four differentially sized and labeled amplicons from the same allele. Informative peaks to assist allele calling then fourfold those generated by the analysis of single PCR amplicons. Our approach proved successful to differentiate all the alleles (N = 13) isolated from eight unrelated birds at a single optimal run temperature and electrophoretic conditions. In particular, we emphasize that this approach may constitute a straight-forward and cost-effective alternative for the genotyping of single or duplicated MHC genes displaying low to moderate sets of divergent alleles. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.Peer Reviewe