Selección de nido y biología reproductiva del Chorlitejo Patinegro Charadrius alexandrinus en playas de la costa oeste de Portugal

Aims: The nest-site selection and breeding biology of Kentish Plover Charadrius alexandrinus were studied on sandy beaches of the Portuguese West coast. Methods: Nest-site characteristics were compared with those of random points and between successful and unsuccessful nests. Breeding parameters (timing of laying, nesting success and egg size) were examined on sandy beaches and these data combined with a literature review to provide a comparison of Kentish Plovers’ breeding parameters between natural (sandy beaches, saline lakes) and man-made coastal habitats (salinas and fish-farms). Results and Conclusions: Three temporal peaks of breeding activity were distinguished: end of April, mid May and end of June. Most nests were located less than 100 meters from the nearest active nest. The dimen- sions (breadth and volume) of the eggs from late clutches were significantly smaller than those from eggs of early and intermediate clutches. Nesting success was 32% (12.3% using the Mayfield method). There were significant differences in nesting success between the four studied beaches (56% of all clutches produced chicks in Gala while only 18% of all clutches produced chicks in Costinha). Despite the lower success of in- termediate clutches no significant difference in nesting success was found between early, intermediate and late clutches. There was a higher probability of finding nest-sites near objects and in areas with a higher cover of sparse vegetation and objects than were random points. Successful nests were placed farther from the nearest mammal footprint, were closer to the nearest vehicle sandmark and had a lower cover of shells and pebbles than did unsuccessful nests. Nesting success was highly variable for both natural and man-made coastal ha- bitats and affected mainly by predation and flooding. In terms of conservation it seems important to maintain habitat diversity for Kentish PloversObjetivos: Se estudia la selección de nido y la biología reproductiva del Chorlitejo Patinegro en playas de la costa oeste de Portugal. Métodos: Las características del emplazamiento de nidos tanto exitosos como fracasados se comparan con las características de puntos tomados al azar. Se analizaron variables descriptoras de la reproducción tales como, fecha de puesta, éxito y tamaño de los huevos. Así mismo, se utilizaron los datos obtenidos además de datos procedentes de la bibliografía para realizar una comparación de la reproducción en hábitats naturales (playas y lagos salinos) y en hábitats artificiales (salinas y piscifactorías). Resultados y conclusiones: Se distinguieron tres máximos temporales durante la reproducción: finales de abril, mediados de mayo y finales de junio. La mayor parte de los nidos se situaron a menos de 100 metros de otro nido ocupado. Los huevos de las puestas tardías fueron significativamente más pequeños (anchura y vo- lumen) que los huevos procedentes de puestas tempranas o intermedias. El éxito reproductivo fue del 32% (12,3% utilizando el método de Mayfield). Se encontraron diferencias significativas en el éxito de los nidos en- tre las cuatro playas estudiadas (el 56% de las puestas produjeron pollos en Gala mientras que solo el 18% de las puestas produjeron pollos en Costinha). A pesar del bajo éxito de las puestas intermedias no se encontraron diferencias significativas entre las puestas tempranas, intermedias o tardías. Los nidos se situaron con una ma- yor probabilidad en la proximidad de objetos o en zonas con una menor cobertura de vegetación en compara- ción con los puntos tomados al azar. Los nidos exitosos se situaron en los lugares más alejados de huellas de mamíferos, estuvieron más cerca de lugares donde se encontraron huellas de vehículos y tuvieron una menor cobertura de piedras y/o conchas que los nidos fracasados. El éxito reproductor fue muy variable tanto en los hábitats naturales como en los artificiales, y fueron afectados fundamentalmente por depredación e inundación. En relación a la conservación del Chorlitejo Patinegro, parece importante conservar hábitats diverso

Contamination level and spatial distribution of heavy metals in water and sediments of El Guájaro Reservoir, Colombia

Heavy metals have become a subject of special concern worldwide, mainly due to high persistence in the environment, toxicity, biogeochemical recycling and ecological risk. Therefore, the objective of this investigation was to analyze the spatial–temporal distribution of heavy metals in water and sediments to determine the environmental status of El Guájaro Reservoir, where such studies have not been developed. Two measurement campaigns (dry and wet period) were carried out and eight sampling stations were selected. A comparison of water and sediment quality parameters with existing national and international regulations was done. Also, heavy metal distribution maps were generated, and the geoaccumulation index was calculated to identify sources and sediments contamination level. Based on the obtained results, agriculture and mining activities are the main causes of the reservoir contamination. This metals levels could be a potential risk for the aquatic life and the populations that are supplied from this water body

Oxidative Stress Mediates Physiological Costs of Begging in Magpie (Pica pica) Nestlings

[Background] Theoretical models predict that a cost is necessary to guarantee honesty in begging displays given by offspring to solicit food from their parents. There is evidence for begging costs in the form of a reduced growth rate and immunocompetence. Moreover, begging implies vigorous physical activity and attentiveness, which should increase metabolism and thus the releasing of pro-oxidant substances. Consequently, we predict that soliciting offspring incur a cost in terms of oxidative stress, and growth rate and immune response (processes that generate pro-oxidants substances) are reduced in order to maintain oxidative balance. [Methodology/Principal Findings] We test whether magpie (Pica pica) nestlings incur a cost in terms of oxidative stress when experimentally forced to beg intensively, and whether oxidative balance is maintained by reducing growth rate and immune response. Our results show that begging provokes oxidative stress, and that nestlings begging for longer bouts reduce growth and immune response, thereby maintaining their oxidative status. [Conclusions/Significance] These findings help explaining the physiological link between begging and its associated growth and immunocompetence costs, which seems to be mediated by oxidative stress. Our study is a unique example of the complex relationships between the intensity of a communicative display (begging), oxidative stress, and life-history traits directly linked to viability.GM-R was supported by the Spanish Government (Ministerio de Ciencia y Tecnología, “Juan de la Cierva” program), and TR was supported by the Consejo Superior de Investigaciones Científicas (CSIC; Proyectos Intramurales Especiales)

Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits

Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species – the great tit Parus major – at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), using 22 microsatellite markers. Overall we found a low but significant genetic differentiation among sites (FST = 0.008). Genetic differentiation was higher, and genetic diversity lower, in south-western Europe. These regional differences were statistically best explained by winter temperature. Overall, our results suggest that great tits form a single patchy metapopulation across Europe, in which genetic differentiation is independent of geographical distance and gene flow may be regulated by environmental factors via movements related to winter severity. This might have important implications for the evolutionary trajectories of sub-populations, especially in the context of climate change, and calls for future investigations of local differences in costs and benefits of philopatry at large scales

Interaction of climate change with effects of conspecific and heterospecific density on reproduction

We studied the relationship between temperature and the coexistence of great titParus majorand blue titCyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.Peer reviewe

Effects of interspecific coexistence on laying date and clutch size in two closely related species of hole-nesting birds

Coexistence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole‐nesting taxa, constitutes a classic example of species co‐occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variations in coexistence and its consequences for competition remain poorly understood. We used an extensive database on reproduction in nest boxes by great and blue tits based on 87 study plots across Europe and Northern Africa during 1957–2012 for a total of 19,075 great tit and 16,729 blue tit clutches to assess correlative evidence for a relationship between laying date and clutch size, respectively, and density consistent with effects of intraspecific and interspecific competition.In an initial set of analyses, we statistically controlled for a suite of site‐specific variables. We found evidence for an effect of intraspecific competition on blue tit laying date (later laying at higher density) and clutch size (smaller clutch size at higher density), but no evidence of significant effects of intraspecific competition in great tits, nor effects of interspecific competition for either species.To further control for site‐specific variation caused by a range of potentially confounding variables, we compared means and variances in laying date and clutch size of great and blue tits among three categories of difference in density between the two species. We exploited the fact that means and variances are generally positively correlated. If interspecific competition occurs, we predicted a reduction in mean and an increase in variance in clutch size in great tit and blue tit when density of heterospecifics is higher than the density of conspecifics, and for intraspecific competition, this reduction would occur when density of conspecifics is higher than the density of heterospecifics. Such comparisons of temporal patterns of means and variances revealed evidence, for both species, consistent with intraspecific competition and to a smaller extent with interspecific competition.These findings suggest that competition associated with reproductive behaviour between blue and great tits is widespread, but also varies across large spatial and temporal scales.</div

The great tit HapMap project: a continental‐scale analysis of genomic variation in a songbird

A major aim of evolutionary biology is to understand why patterns of genomic diversity vary within taxa and space. Large-scale genomic studies of widespread species are useful for studying how environment and demography shape patterns of genomic divergence. Here, we describe one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning ~30 degrees of latitude and 40 degrees of longitude – almost the entire geographical range of the European subspecies. Genome-wide variation was consistent with a recent colonisation across Europe from a South-East European refugium, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear ‘islands of differentiation’, even among populations with very low levels of genome-wide differentiation. Low local recombination rates were a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination causes highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, probably as a result of recent directional selection at the species' range edges. Haplotype-based measures of selection were related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into spatio-temporal evolutionary dynamics

Variation in clutch size in relation to nest size in birds

Peer reviewe

Color aerial photography and contour drawing lines of known reduced space for orienteering activity in 2–3-year-olds children: exploratory study

As crianças conseguem orientar-se procurando objetos escondidos com uma fotografia aérea a cores. Fomos verificar se crianças de 2-3 anos o conseguiriam através de desenho de contornos. 15 crianças (2,6±0,5 anos, 2 anos=6; meninas=8), procuraram individualmente botões parcialmente escondidos em 5 móveis da sua sala, à sua esquerda, direita e centro; divididas em 2 grupos: fotografia (F)- com fotografia aérea a cores (2,6±0,5 anos, 2 anos=3; meninas=3); contornos (C)- com desenho de contornos dos móveis e paredes da F (2,6±0,5 anos, 2 anos=3; meninas=5). No C, 50% precisou ajuda da educadora para interpretar a imagem; na F, 87,5%, não careceu de qualquer ajuda. As do C, consultaram significativamente mais vezes a imagem (p=,024), mas houve um menino (2 anos) que só consultou uma vez e teve sucesso total. No F, 85,7% das crianças procurou 1º os botões mais próximos, associado significativamente às 87,5% que iniciou pelo botão à sua esquerda (p=,008). Em F e C, não houve diferença entre géneros. No F, as de 2 anos encontraram significativamente menos botões, que as de 3 anos, que encontraram todos (p=,028). As do F demoraram ≈2min a realizar a atividade de orientação (O). Como mapa para O, com crianças de 2-3 anos, F foi mais fácil de usar que C. Pode haver crianças de 2 anos com elevada capacidade de uso de C como mapa. Para O, com crianças de 2 anos, sugere-se usar objetos a encontrar de dimensão não pequena e mais destacáveis visivelmente.Children can find their way around looking for hidden objects with a color aerial photograph. We went to see if 2–3-year-olds could do it through contour drawing. 15 children (2.6±0.5 years, 2 years=6; girls=8), individually looked for partially hidden buttons on 5 pieces of furniture in their living room, on their left, right and center; divided into 2 groups: photograph (F)- with aerial color photograph (2.6±0.5 years, 2 years=3; girls=3); contours (C) - with drawing of furniture and walls contours of F (2.6±0.5 years, 2 years=3; girls=5). In C, 50% needed help from the educator to interpret the image; in F, 87.5% did not need any help. Those in C consulted the image significantly more times (p=.024), but there was a boy (2 years old) who only consulted it once and was completely successful. In F, 85.7% of the children looked for the nearest buttons first, significantly associated with the 87.5% who started with the button on their left (p=.008). In F and C, there was no difference between genders. In F, the 2-year-olds found significantly fewer buttons than the 3-year-olds, who found all of them (p=.028). Those from F took ≈2min to perform the orientation activity (O). As a map for O, with 2–3-year-olds, F was easier to use than C. There may be 2-year-olds with a high ability to use C as a map. For O, with 2-year-old children, it is suggested to use objects to find that are not small in size and more visibly detachable.info:eu-repo/semantics/publishedVersio