311 research outputs found

    Spatial ecology of the Red Kite (Milvus milvus) during the breeding period in Spain

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    Studies focusing on the spatial ecology of the Red Kite (Milvus milvus) during the breeding season are scarce, despite this season having major importance in its conservation. Spain has one of the largest breeding populations of this species, but it is very threatened in this country. Here, 28 Red Kites were tagged in Spain with GPS satellite transmitters to study the movements of breeding adults during the breeding season (March-June), evaluating the differences according to sex, and investigating the habitat selection. The area used by females was smaller than the used by males (95% KDE = 4.48 vs. 3.30 km2). Females also traveled less distance per hour and remained closer to the nest. Thus, females had a higher frequency of locations at distances 1 km. Distances recorded at >5 km were scarce for both sexes, and maximum distances reached were usually (61% of seasons) less than 15 km. Both sexes increased the frequency of movements between 1–3 km during the central hours of the day. Red Kites mainly used areas occupied by non-irrigated arable land, forests, scrubs, and herbaceous vegetation. The selection of certain types of crops highlights the importance of the agroforestry landscape for the conservation of the species. On the other hand, we documented for the first time how part of the Spanish breeding population is a short-distance migrant within the Iberian Peninsula while other part of the population makes post-breeding movements during summer

    How can the home range of the Lesser Kestrel be affected by a large civil infrastructure?

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    Background: The loss of traditional agropastoral systems, with the consequent reduction of foraging habitats and prey availability, is one of the main causes for the fast decline of Lesser Kestrel (Falco naumanni). To promote the conservation of the Lesser Kestrel and their habitats, here we studied the foraging activities patterns of this species during the breeding season. Methods: Between 2016 and 2017, we captured and tagged 24 individuals with GPS dataloggers of two colonies in Villena (eastern Spain) with the goals of estimating the home range sizes of males and females, evaluating the differences in spatial ecology between two colonies located in different environments: natural and beside a thermosolar power plant, and investigating habitat selection. Results: Considering the distances before July 15, date until which it can be assured that the chicks remain in the nest in our colonies, there were significant differences with the distances to the nest in relation to the colony of the individuals: Lesser Kestrels from the thermosolar power plant colony had a greater average distance. The average size of home range areas was 13.37 km2 according to 95% kernel, and there were also significant differences in relation to colony: the individuals from the thermosolar power plant colony used a larger area (22.03 ± 4.07 km2) than those from the other colony (9.66 ± 7.68 km2). Birds showed preference for non-irrigated arable lands and pastures. Conclusions: Despite the differences between the two colonies, the home ranges of both are smaller or similar to those observed in other European colonies. This suggests that Lesser Kestrels continue to have adequate habitats and a good availability of prey. Therefore, the extension and proximity of the plant does not imply a great alteration, which highlights the importance of maintaining the rest of the territory in good conditions to minimize the impact.Funding for the project on studying the spatial ecology of Lesser Kestrel was provided by Enerstar S.A. (http://www.enerstar.es). JV is supported by a FPU grant of Spanish Ministry of Education (reference FPU014/04671)

    Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

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    Red Kite shows a great variability in its migration strategies: most individuals in north-eastern Europe are migrants, but there is also a growing number of sedentary individuals. Here, we tagged 49 Red Kites wintering in Spain with GPS/satellite transmitters between 2013 and 2020 to study the autumn and spring migration between the breeding or summering areas in Central Europe and the wintering quarters in Spain. In first place, differences between immatures and adults were found for spring migration. Adults began the spring migration towards the northeast in February–March while the immature individuals began to migrate significantly later and showing a wider date range (February-June). Adults also takes significantly less days to arrive at their destinations (12 ± 5 days) and cover more distance per day (134.2 ± 37.1 km/day) than immatures (19 ± 11 days and 98.9 ± 21.2 km/day). In second place, we also found differences between spring and autumn migration (excluding immatures). Spring migrations were clearly faster and with less stopovers days than autumn migrations. Autumn migration began between mid-October and late November and two different behaviours were observed: most birds made a quick migration direct to the wintering areas with only some days of stopovers, but others prolonged the migration with long stops along the route. These results highlight a great variation in the migratory movements of Red Kite, not only according to age but also between individuals and seasons.Funding for the tagging was provided by Fundación Iberdrola España, Gobierno del País Vasco, Fundación Biodiversidad, Grupo Ornitológico SEO-Monticola, FAB and Binaced townhall. NorthStar donated two GPS-GSM prototype units to deploy on Kites. J. Vidal-Mateo is supported by a FPU grant of Spanish Ministry of Education (reference FPU014/04671)

    Reproductive success of Whiskered Tern Chlidonias hybrida in eastern Spain in relation to water level variation

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    Background. A study on the Whiskered Tern Chlidonias hybrida was carried out between 2002 and 2009 in wetlands of eastern Spain to evaluate how water level fluctuation affects its reproductive success (hatching, fledgling and breeding success). This species is catalogued as Vulnerable in Spain and has an unfavorable conservation status in Europe. Methods. Our study includes 18 sampling areas from five wetlands, covering a total of 663 nests, 1,618 eggs, 777 nestlings and 225 fledglings. The colonies were visited at least twice per week in breeding period. The number of eggs and/or nestlings present in each nest were annotated each time the colonies were visited with the aim to compare the evolution of these parameters with time. Hatching success was calculated as the proportion of egg that hatched successfully. Fledgling success and breeding success were calculated as the proportion of chicks that fledged successfully and the proportion of eggs that produced fledglings. We used the Kruskal–Wallis test to analyze the differences in the dependent variables hatching, fledgling and breeding success among the wetlands and the sampling areas. We explored the relationship between the different reproductive success with the average fluctuation rate and the anchoring depth of nests, using statistics of the linear regression. Results. It was observed that the reproductive success varied significantly in the interaction among the different categories of water level fluctuation and the different areas (using the Kruskal–Wallis test). Our records showed that pronounced variations in water level destroyed several nests, which affected the Whiskered Tern reproductive success. Considering all events that occurred in 18 areas, the mean (±SD) of nests, eggs and nestlings that were lost after water level fluctuations were of 25.60 ± 21.79%, 32.06 ± 27.58% and 31.91 ± 21.28% respectively, also including the effects of rain and predation. Discussion. Unfavorable climatic events, such as strong wind, rain or hail, also caused the loss of nests, eggs and nestlings, even when wetland water levels remained constant. The influence of the anchorage depth of the nest and the water level fluctuation rate were analyzed and did not provide statistically significant results. It was not possible to establish a clear pattern on these latter variables, so further studies are needed to obtain more significant results. We propose to undertake similar studies in wetlands where the water level can be regulated, with the range of nest anchorage depth on the emergent vegetation being between 30 and 60 cm, which could improve the reproductive success in this kind of habitats. As recommendation, in water level controlled wetlands (that use sluices), it should not vary more than ±6 cm in a short time (1–2 days) once the nests are established since it negatively affects their reproductive success.This work was supported by Alicante University, Department of Environmental Sciences and Natural Resources

    Wind effects on the migration routes of trans-Saharan soaring raptors: geographical, seasonal and interspecific variation.

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    Wind is among the most important environmental factors shaping birds' migration patterns. Birds must deal with the displacement caused by crosswinds and their behavior can vary according to different factors such as flight mode, migratory season, experience, and distance to goal areas. Here we analyze the relationship between wind and migratory movements of three raptor species which migrate by soaring-gliding flight: Egyptian vulture Neophron percnopterus , booted eagle Aquila pennata , and short-toed snake eagle Circaetus gallicus . We analyzed daily migratory segments (i.e., the path joining consecutive roosting locations) using data recorded by GPS satellite telemetry. Daily movements of Egyptian vultures and booted eagles were significantly affected by tailwinds during both autumn and spring migrations. In contrast, daily movements of short-toed eagles were only significantly affected by tailwinds during autumn migration. The effect of crosswinds was significant in all cases. Interestingly, Egyptian vultures and booted eagles showed latitudinal differences in their behavior: both species compensated more frequently at the onset of autumn migration and, at the end of the season when reaching their wintering areas, the proportion of drift segments was higher. In contrast, there was a higher drift at the onset of spring migration and a higher compensation at the end. Our results highlight the effect of wind patterns on the migratory routes of soaring raptors, with different outcomes in relation to species, season, and latitude, ultimately shaping the loop migration patterns that current tracking techniques are showing to be widespread in many long distance migrants

    Non-Invasive Archaeological Methodologies for the Analysis of the Port Structures of Portus Ilicitanus (Santa Pola, Alicante)

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    The traditional identification of the ancient port of Ilici with the current town of Santa Pola in Alicante (Spain) has been based on a small number of punctual, unconnected, and too partial archaeological interventions. Since 2017, a program of geophysical surveys has been performed with a Stream X model multi-channel georadar IDS. This program has been focused mainly on the so-called Mercado de Viguetes, an area in which archaeological excavations have hardly been carried out. The geophysical surveys have allowed us to draw part of the urban fabric of the central core of the Portus Ilicitanus, revealing a set of structures that can be assimilated into a port area: warehouses, houses, open spaces, and decantation basins to produce salted fish, and the probable eastern boundary of the complex identified with the port dock. Altogether, two predominant alignments can be assimilated into the Early Imperial and Late Imperial construction phases. Non-invasive archaeological methodologies have become the main resource for archaeological analysis and heritage protection in view of the current impossibility of carrying out archaeological excavations in this area of Santa Pola.This research was funded by the Spanish Ministerio de Ciencia e Innovación, grant number PID2019-107264GB-I00 and PGC2018-099843-B-I00

    Search Foraging Strategies of Migratory Raptors Under Different Environmental Conditions

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    Several studies have shown in different organisms how their movements can be fitted to different patterns to optimize search of food resources. According to abundance and availability of resources, different strategies will be optimal, such as Lévy and Brownian random search. We analyze the movement patterns of four species of migratory raptors with different degrees of ecological specialization in diet during the breeding and wintering periods to evaluate the differences according to species and season: the Egyptian Vulture, the Short-toed Snake Eagle, the Booted Eagle, and the Red Kite. From GPS locations, we obtained a set of segments and lengths that were analyzed to verify their fitting to the functions of Lévy and Brownian strategies. Egyptian Vulture’s trajectories fitted to both patterns during the breeding period, whereas during the wintering period most trajectories fitted a Brownian pattern. In the case of the Short-toed Eagle, fit was greater to a Lévy strategy throughout the year, while Booted Eagles and Red Kites exhibited a combination of search patterns. These differences could be accounted for different feeding strategies and environmental context over the annual cycle. In species with a specialized diet (i.e., Short-toed Eagle) the Lévy pattern would maximize the encounters with scarce and unpredictable resources, whereas for species with a broad trophic niche (i.e., Booted Eagle and Red Kite), movements could be adapted to exploit different resources according to their abundance. Scavengers like the Egyptian Vulture shift also between search strategies according to the distribution of carrion. Therefore, the analysis of food search patterns can be used as an indirect indicator to track changes in food availability across a broad range of environmental conditions. This is particularly important under the current context of global change which is largely expected to affect migratory species that spend their vital cycle in distant areas.Tracking of Booted Eagles and Red Kites has been made within the “Migra” program (www.migraciondeaves.org/en/) developed by SEO/BirdLife and financed by Fundación Iberdrola España. The Basque Government and the Biodiversity Foundation financed the tagging of several Red Kites in Spain. Tracking of Italian individuals was funded by Gallipoli Cognato Piccole Dolomiti Lucane Regional Park (Italy). Servicio de Vida Silvestre (Generalitat Valenciana) and different local governments funded part of the tagging. JV-M was supported by a FPU grant of Spanish Ministry of Education (reference FPU014/04671)

    Performance analysis of a new packet trace compressor based on TCP flow clustering

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    In this paper we study the properties of a new packet trace compression method based on clustering of TCP flows. With our proposed method, the compression ratio that we achieve is around 3%, reducing the file size, for instance, from 100 MB to 3 MB. Although this specification defines a lossy compressed data format, it preserves important statistical properties present into original trace. In order to validate the method, memory performance studies were done with the Radix Tree algorithm executing a trace generated by our method. To give support to these studies, measurements were taken of memory access and cache miss ratio. For the time, the results have showed that our proposed method provides a good solution for packet trace compression.Peer ReviewedPostprint (published version

    A versatile CMOS transistor array IC for the statistical characterization of time-zero variability, RTN, BTI, and HCI

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    Statistical characterization of CMOS transistor variability phenomena in modern nanometer technologies is key for accurate end-of-life prediction. This paper presents a novel CMOS transistor array chip to statistically characterize the effects of several critical variability sources, such as time-zero variability (TZV), random telegraph noise (RTN), bias temperature instability (BTI), and hot-carrier injection (HCI). The chip integrates 3136 MOS transistors of both pMOS and nMOS types, with eight different sizes. The implemented architecture provides the chip with a high level of versatility, allowing all required tests and attaining the level of accuracy that the characterization of the above-mentioned variability effects requires. Another very important feature of the array is the capability of performing massively parallel aging testing, thus significantly cutting down the time for statistical characterization. The chip has been fabricated in a 1.2-V, 65-nm CMOS technology with a total chip area of 1800 x 1800 µm²

    Unraveling the effect of silent, intronic and missense mutations on VWF splicing : contribution of next generation sequencing in the study of mRNA

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    Large studies in von Willebrand disease patients, including Spanish and Portuguese registries, led to the identification of >250 different mutations. It is a challenge to determine the pathogenic effect of potential splice site mutations on VWF mRNA. This study aimed to elucidate the true effects of 18 mutations on VWF mRNA processing, investigate the contribution of next-generation sequencing to in vivo mRNA study in von Willebrand disease, and compare the findings with in silico prediction. RNA extracted from patient platelets and leukocytes was amplified by RT-PCR and sequenced using Sanger and next generation sequencing techniques. Eight mutations affected VWF splicing: c.1533+1G>A, c.5664+2T>C and c.546G>A (p.=) prompted exon skipping; c.3223-7_3236dup and c.7082-2A>G resulted in activation of cryptic sites; c.3379+1G>A and c.7437G>A) demonstrated both molecular pathogenic mechanisms simultaneously; and the p.Cys370Tyr missense mutation generated two aberrant transcripts. Of note, the complete effect of three mutations was provided by next generation sequencing alone because of low expression of the aberrant transcripts. In the remaining 10 mutations, no effect was elucidated in the experiments. However, the differential findings obtained in platelets and leukocytes provided substantial evidence that four of these would have an effect on VWF levels. In this first report using next generation sequencing technology to unravel the effects of VWF mutations on splicing, the technique yielded valuable information. Our data bring to light the importance of studying the effect of synonymous and missense mutations on VWF splicing to improve the current knowledge of the molecular mechanisms behind von Willebrand disease. identifier:02869074
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