| from cradle to early grave: juvenile mortality in european shags phalacrocorax aristotelis results from inadequate development of foraging proficiency. | in most long-lived animal species, juveniles survive less well than adults. a potential mechanism is inferior foraging skills but longitudinal studies that follow the development of juvenile foraging are needed to test this. we used miniaturized activity loggers to record daily foraging times of juvenile and adult european shags phalacrocorax aristotelis from fledging to the following spring. juveniles became independent from their parents 40 days post-fledging. they compensated for poor foragin ... | 2007 | 17504733 |
| developmental plasticity of physiology and morphology in diet-restricted european shag nestlings (phalacrocorax aristotelis). | growing animals may exhibit developmental plasticity as an adaptation to variability in the environmental conditions during development. we examined physiological and morphological responses to short-term food shortage of 12-16-day-old european shag nestlings kept under laboratory conditions. after 4 days on a weight maintenance diet, the resting metabolic rate (rmr) of diet-restricted nestlings was 36.5% lower compared with control fed nestlings, after controlling for body mass. this response w ... | 2004 | 15498952 |
| yolk pcb and plasma retinol concentrations in shag (phalacrocorax aristotelis) hatchlings. | to evaluate the possibilities of applying plasma retinol as a biomarker of response in seabirds exposed to chronic low levels of organochlorines, the relationship between yolk content of polychlorinated biphenyls (pcbs) and plasma retinol levels were studied in newly hatched shag chicks (phalacrocorax aristotelis) from the coast of central norway. the mean concentration of 29 pcb-congeners (sigmapcb) in the yolk sac was 1.22 microgram/g ww (wet weight basis) (sd = 0.57, n = 10), or 17.99 ng/g lw ... | 1999 | 10047599 |
| reproductive performance of resident and migrant males, females and pairs in a partially migratory bird. | quantifying among-individual variation in life-history strategies, and associated variation in reproductive performance and resulting demographic structure, is key to understanding and predicting population dynamics and life-history evolution. partial migration, where populations comprise a mixture of resident and seasonally migrant individuals, constitutes a dimension of life-history variation that could be associated with substantial variation in reproductive performance. however, such variati ... | 2017 | 28502109 |
| ten years after the prestige oil spill: seabird trophic ecology as indicator of long-term effects on the coastal marine ecosystem. | major oil spills can have long-term impacts since oil pollution does not only result in acute mortality of marine organisms, but also affects productivity levels, predator-prey dynamics, and damages habitats that support marine communities. however, despite the conservation implications of oil accidents, the monitoring and assessment of its lasting impacts still remains a difficult and daunting task. here, we used european shags to evaluate the overall, lasting effects of the prestige oil spill ... | 2013 | 24130877 |
| stay-at-home strategy brings fitness benefits to migrants. | in focus: lok, t., veldhoen, l., overdijk, o., tinbergen, j. m., & piersma, t. (2017). an age-dependent fitness cost of migration? old trans-saharan migrating spoonbills breed later than those staying in europe, and late breeders have lower recruitment. journal of animal ecology, 86, 998-1009. in focus: grist, h., daunt, f., wanless, s., burthe, s. j., newell, m. a., harris, m. p., & reid, j. m. (2017). reproductive performance of resident and migrant males, females and pairs in a partially migr ... | 2017 | 28797137 |
| a broad cocktail of environmental pollutants found in eggs of three seabird species from remote colonies in norway. | eggs of 3 seabird species, common eider (somateria mollisima), european shag (phalacrocorax aristotelis aristotelis), and european herring gull (larus argentatus), were surveyed for a broad range of legacy and emerging pollutants to assess chemical mixture exposure profiles of seabirds from the norwegian marine environment. in total, 201 chemical substances were targeted for analysis ranging from metals, organotin compounds, polycyclic aromatic hydrocarbons (pahs), polychlorinated biphenyls (pcb ... | 2015 | 25728907 |
| anisakid infection in the european shag phalacrocorax aristotelis aristotelis. | a total of 100 specimens of the european shag phalacrocorax aristotelis aristotelis were examined for anisakid infections in the south-east north atlantic. the taxonomic status of the anisakid nematodes was studied by structural analysis using light and scanning electron microscopy. two species, contracaecum septentrionale and c. rudolphii a (nematoda: ascaridoidea), occurred in the european shag with high values of prevalence and mean intensities of infection. these constitute new host records ... | 2001 | 11551308 |
| permanent genetic resources added to molecular ecology resources database 1 april 2010 - 31 may 2010. | this article documents the addition of 396 microsatellite marker loci to the molecular ecology resources database. loci were developed for the following species: anthocidaris crassispina, aphis glycines, argyrosomus regius, astrocaryum sciophilum, dasypus novemcinctus, delomys sublineatus, dermatemys mawii, fundulus heteroclitus, homalaspis plana, jumellea rossii, khaya senegalensis, mugil cephalus, neoceratitis cyanescens, phalacrocorax aristotelis, phytophthora infestans, piper cordulatum, pte ... | 2010 | 21565124 |
| perfluorinated and other persistent halogenated organic compounds in european shag (phalacrocorax aristotelis) and common eider (somateria mollissima) from norway: a suburban to remote pollutant gradient. | samples of two marine bird species, european shag (phalacrocorax aristotelis) and common eider (somateria mollissima) sampled at a remote coastal site in norway were analysed for pops and pfcs. additionally samples of common eider were analysed from two other locations in norway, representing a gradient from "densely populated" to "remote". the variety, concentration and distribution of lipophilic pops in comparison to pfcs were investigated. pcbs were the dominating group of contaminants in the ... | 2009 | 19836057 |
| molecular evidence for the occurrence of contracaecum rudolphii a (nematoda: anisakidae) in shag phalacrocorax aristotelis (linnaeus) (aves: phalacrocoracidae) from sardinia (western mediterranean sea). | specimens of contracaecum rudolphii hartwich, 1964 (nematoda: anisakidae) from phalacrocorax aristotelis (linnaeus) from the archipelago of la maddalena (sardinia, western mediterranean sea) were characterised genetically and compared with c. rudolphii a sensu d'amelio et al. 1990 and c. rudolphii b sensu d'amelio et al. 1990 from phalacrocorax carbo sinensis (blumenbach) from north-eastern italy, and with c. rudolphii c sensu d'amelio et al. 2007 from phalacrocorax auritus (lesson) from west-ce ... | 2008 | 18571974 |
| exposure and effects of persistent organic pollutants in european shag (phalacrocorax aristotelis) hatchlings from the coast of norway. | although the coast of norway is relatively clean regarding contaminants compared to areas of europe with higher density of both people and industry, levels of persistent organic pollutants (pops) exist in the marine ecosystem that may cause chronic exposure effects in wildlife. in this study, polychlorinated biphenyls (pcbs), some organochlorinated pesticides (ocps), polybrominated diphenyl ethers (pbdes), and hexabromocyclododecane (hbcd) were analyzed in yolk sac of european shag (phalacrocora ... | 2006 | 16494241 |
| energetic costs of diving and thermal status in european shags (phalacrocorax aristotelis). | diving is believed to be very costly in cormorants (phalacrocoracidae) when compared with other avian divers because of their poor insulation and less-efficient foot propulsion. it was therefore suggested that cormorants might employ a behavioural strategy to reduce daily energy expenditure by minimizing the amount of time spent in water. however, european shags (phalacrocorax aristotelis) have been observed to spend up to 7 h day(-1) diving in water of around 5-6 degrees c. to gain a better und ... | 2005 | 16155218 |
| genetic evidence for the existence of sibling species within contracaecum rudolphii (hartwich, 1964) and the validity of contracaecum septentrionale (kreis, 1955) (nematoda: anisakidae). | specimens of contracaecum rudolphii sensu lato (s.l.) (nematoda: anisakidae) from phalacrocorax carbo sinensis from northeastern and central italy were characterised genetically and compared with those from phalacrocorax aristotelis from galician coasts, spain (identified as c. rudolphii a by multilocus enzyme electrophoresis) and with specimens of c. septentrionale from alca torda from the galician coasts, spain. the first (its-1) and second (its-2) internal transcribed spacers (its) of ribosom ... | 2005 | 15928905 |
| longitudinal bio-logging reveals interplay between extrinsic and intrinsic carry-over effects in a long-lived vertebrate. | carry-over effects have major implications for individual fitness and population and evolutionary dynamics. the strength of these effects is dependent on an individual's intrinsic performance and the environmental conditions it experiences. however, understanding the relative importance of environmental and intrinsic effects underpinning seasonal interactions has proved extremely challenging, since they covary. a powerful approach is longitudinal measurement of individuals across a range of cond ... | 2014 | 25230460 |
| the metabolism of organochlorine compound by microsomal enzymes of the shag (phalacrocorax aristotelis). | 1. the activities of microsomal enzymes of adult male shags (phalacrocorax aristotelis) towards the organochlorine substrates hhdn, hce and heom were compred with those of microsomal enzymes of the adult male wistar rat. 2. liver homogenates showed similar epoxide hydrase activity to kidney homogenates in the shag, but in the rat liver preparations was much more active than the kidney preparation. 3. liver microsomes of the shag showed smaller than 8% of the epoxide hydrase activity and smaller ... | 1975 | 1140184 |
| factors affecting the foraging behaviour of the european shag: implications for seabird tracking studies. | seabird tracking has become an ever more popular tool to aid environmental procedures such as the designation of marine protected areas and environmental impact assessments. however, samples used are usually small and little consideration is given to experimental design and sampling protocol. european shags phalacrocorax aristotelis were tracked using gps technology over three breeding seasons and the following foraging trip characteristics: trip duration, trip distance, maximum distance travell ... | 2014 | 24882884 |
| long-term reproductive impairment in a seabird after the prestige oil spill. | large oil spills are dramatic perturbations on marine ecosystems, and seabirds are one of the worst affected organisms in such events. it has been argued that oil spills may have important long-term consequences on marine organisms, but supporting evidence remains scarce. the european shag (phalacrocorax aristotelis) was strongly impacted at population level by the prestige oil spill, the biggest spillage in the eastern north atlantic. in this paper, we report on the long-term consequences on re ... | 2014 | 24789139 |
| stress exposure in early post-natal life reduces telomere length: an experimental demonstration in a long-lived seabird. | exposure to stressors early in life is associated with faster ageing and reduced longevity. one important mechanism that could underlie these late life effects is increased telomere loss. telomere length in early post-natal life is an important predictor of subsequent lifespan, but the factors underpinning its variability are poorly understood. recent human studies have linked stress exposure to increased telomere loss. these studies have of necessity been non-experimental and are consequently s ... | 2014 | 24648221 |
| indirect effects of parasitism: costs of infection to other individuals can be greater than direct costs borne by the host. | parasitic infection has a direct physiological cost to hosts but may also alter how hosts interact with other individuals in their environment. such indirect effects may alter both host fitness and the fitness of other individuals in the host's social network, yet the relative impact of direct and indirect effects of infection are rarely quantified. during reproduction, a host's social environment includes family members who may be in conflict over resource allocation. in such situations, infect ... | 2015 | 26156765 |
| contrasting responses of male and female foraging effort to year-round wind conditions. | there is growing interest in the effects of wind on wild animals, given evidence that wind speeds are increasing and becoming more variable in some regions, particularly at temperate latitudes. wind may alter movement patterns or foraging ability, with consequences for energy budgets and, ultimately, demographic rates. these effects are expected to vary among individuals due to intrinsic factors such as sex, age or feeding proficiency. furthermore, this variation is predicted to become more mark ... | 2015 | 26283625 |
| european shags optimize their flight behavior according to wind conditions. | aerodynamics results in two characteristic speeds of flying birds: the minimum power speed and the maximum range speed. the minimum power speed requires the lowest rate of energy expenditure per unit time to stay airborne and the maximum range speed maximizes air distance traveled per unit of energy consumed. therefore, if birds aim to minimize the cost of transport under a range of wind conditions, they are predicted to fly at the maximum range speed. furthermore, take-off is predicted to be st ... | 2016 | 26847559 |
| between-individual variation in nematode burden among juveniles in a wild host. | parasite infection in young animals can affect host traits related to demographic processes such as survival and reproduction, and is therefore crucial to population viability. however, variation in infection among juvenile hosts is poorly understood. experimental studies have indicated that effects of parasitism can vary with host sex, hatching order and hatch date, yet it remains unclear whether this is linked to differences in parasite burdens. we quantified gastrointestinal nematode burdens ... | 2017 | 27873556 |
| helminth burden and ecological factors associated with alterations in wild host gastrointestinal microbiota. | infection by gastrointestinal helminths of humans, livestock and wild animals is common, but the impact of such endoparasites on wild hosts and their gut microbiota represents an important overlooked component of population dynamics. wild host gut microbiota and endoparasites occupy the same physical niche spaces with both affecting host nutrition and health. however, associations between the two are poorly understood. here we used the commonly parasitized european shag (phalacrocorax aristoteli ... | 2017 | 27983724 |
| genetic structure in the european endemic seabird, phalacrocorax aristotelis, shaped by a complex interaction of historical and contemporary, physical and nonphysical drivers. | geographically separated populations tend to be less connected by gene flow, as a result of physical or nonphysical barriers preventing dispersal, and this can lead to genetic structure. in this context, highly mobile organisms such as seabirds are interesting because the small effect of physical barriers means nonphysical ones may be relatively more important. here, we use microsatellite and mitochondrial data to explore the genetic structure and phylogeography of atlantic and mediterranean pop ... | 2017 | 28028864 |
| validating accelerometry estimates of energy expenditure across behaviours using heart rate data in a free-living seabird. | two main techniques have dominated the field of ecological energetics: the heart rate and doubly labelled water methods. although well established, they are not without their weaknesses, namely expense, intrusiveness and lack of temporal resolution. a new technique has been developed using accelerometers; it uses the overall dynamic body acceleration (odba) of an animal as a calibrated proxy for energy expenditure. this method provides high-resolution data without the need for surgery. significa ... | 2017 | 28258086 |
| climate influences fledgling sex ratio and sex-specific dispersal in a seabird. | climate influences the dynamics of natural populations by direct effects over habitat quality but also modulating the phenotypic responses of organisms' life-history traits. these responses may be different in males and females, particularly in dimorphic species, due to sex-specific requirements or constraints. here, in a coastal seabird, the european shag (phalacrocorax aristotelis), we studied the influence of climate (north atlantic oscillation, nao; sea surface temperature, sst) on two sex-r ... | 2013 | 23951144 |
| impacts of parasites in early life: contrasting effects on juvenile growth for different family members. | parasitism experienced early in ontogeny can have a major impact on host growth, development and future fitness, but whether siblings are affected equally by parasitism is poorly understood. in birds, hatching asynchrony induced by hormonal or behavioural mechanisms largely under parental control might predispose young to respond to infection in different ways. here we show that parasites can have different consequences for offspring depending on their position in the family hierarchy. we experi ... | 2012 | 22384190 |
| heterozygosity-fitness correlations in a declining seabird population. | loss of genetic diversity is thought to lead to increased risk of extinction in endangered populations due to decreasing fitness of homozygous individuals. here, we evaluated the presence of inbreeding depression in a long-lived seabird, the european shag (phalacrocorax aristotelis), after a severe decline in population size by nearly 70%. during three reproductive seasons, 85 breeders were captured and genotyped at seven microsatellite loci. nest sites were monitored during the breeding season ... | 2015 | 25626726 |
| pre-fledgling oxidative damage predicts recruitment in a long-lived bird. | empirical evidence has shown that stressful conditions experienced during development may exert long-term negative effects on life-history traits. although it has been suggested that oxidative stress has long-term effects, little is known about delayed consequences of oxidative stress experienced early in life in fitness-related traits. here, we tested whether oxidative stress during development has long-term effects on a life-history trait directly related to fitness in three colonies of europe ... | 2012 | 21865247 |
| seabird feathers as monitors of the levels and persistence of heavy metal pollution after the prestige oil spill. | we measured heavy metal concentrations in yellow-legged gulls (n = 196) and european shags (n = 189) in order to assess the temporal pattern of contaminant exposure following the prestige oil spill in november 2002. we analysed pb, cu, zn, cr, ni and v levels in chick feathers sampled at four colonies during seven post-spill years (2003-2009), and compared results with pre-spill levels obtained from feathers of juvenile shag corpses (grown in spring/summer 2002). following the prestige wreck, cu ... | 2011 | 21764195 |
| fluctuating wing asymmetry and hepatic concentrations of persistent organic pollutants are associated in european shag (phalacrocorax aristotelis) chicks. | in aquatic birds, high body burdens of persistent organic pollutants (pops) have been associated with developmental effects related to growth, increased fluctuating wing asymmetry, and disruption of the thyroid hormone, vitamin a (retinol) and vitamin e (tocopherol) homeostasis. the aim of the present study was to examine if morphological variables (body mass, liver mass, wing length, tarsus length and head length), fluctuating asymmetry of the wings and tarsus, growth rates and endocrine variab ... | 2010 | 19896702 |
| can ethograms be automatically generated using body acceleration data from free-ranging birds? | an ethogram is a catalogue of discrete behaviors typically employed by a species. traditionally animal behavior has been recorded by observing study individuals directly. however, this approach is difficult, often impossible, in the case of behaviors which occur in remote areas and/or at great depth or altitude. the recent development of increasingly sophisticated, animal-borne data loggers, has started to overcome this problem. accelerometers are particularly useful in this respect because they ... | 2009 | 19404389 |
| assessing the effects of the prestige oil spill on the european shag (phalacrocorax aristotelis): trace elements and stable isotopes. | the prestige oil spill resulted in the mortality of several seabird species on the atlantic nw coast of spain. shag casualties were particularly relevant, since populations are resident in the area the whole year round and because of several features which make them highly vulnerable to environmental hazards. ecological catastrophes give us the opportunity of collecting samples which, otherwise, would be difficult to obtain. we examine the potential of shag corpses as bioindicators of inorganic ... | 2008 | 18804260 |
| parasite treatment affects maternal investment in sons. | parasitism can be a major constraint on host condition and an important selective force. theoretical and empirical evidence shows that maternal condition affects relative investment in sons and daughters; however, the effect of parasitism on sex ratio in vertebrates is seldom considered. we demonstrate experimentally that parasitism constrains the ability of mothers to rear sons in a long-lived seabird, the european shag phalacrocorax aristotelis. the effect contributes to the decline in offspri ... | 2008 | 18687923 |
| the demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird. | 1. most scenarios for future climate change predict increased variability and thus increased frequency of extreme weather events. to predict impacts of climate change on wild populations, we need to understand whether this translates into increased variability in demographic parameters, which would lead to reduced population growth rates even without a change in mean parameter values. this requires robust estimates of temporal process variance, for example in survival, and identification of weat ... | 2008 | 18557956 |
| site fidelity and individual variation in winter location in partially migratory european shags. | in partially migratory populations, individuals from a single breeding area experience a range of environments during the non-breeding season. if individuals show high within- and among- year fidelity to specific locations, any annual environmental effect on individual life histories could be reinforced, causing substantial demographic heterogeneity. quantifying within- and among- individual variation and repeatability in non-breeding season location is therefore key to predicting broad-scale en ... | 2014 | 24892676 |
| model selection for integrated recovery/recapture data. | catchpole et al. (1998, biometrics 54, 33-46) provide a novel scheme for integrating both recovery and recapture data analyses and derive sufficient statistics that facilitate likelihood computations. in this article, we demonstrate how their efficient likelihood expression can facilitate bayesian analyses of these kinds of data and extend their methodology to provide a formal framework for model determination. we consider in detail the issue of model selection with respect to a set of recapture ... | 2002 | 12495138 |
| the importance of hatching date for dominance in young shags. | in birds, conditions and experience in the nest may influence the social rank of juveniles after they become independent. three main factors may be involved: (1) mass at fledging, larger birds being better able to compete; (2) brood hierarchy, dominance in the brood continuing after the birds leave the nest; and (3) hatching date, birds hatching earlier having more experience and a greater ability to compete. i studied the effect of these factors on the agonistic behaviour of juvenile european s ... | 2000 | 10973719 |
| andracantha tunitae (acanthocephala) in the shag (phalacrocorax aristotelis) from shetland, scotland. | following the wreck of the oil tanker braer on the coast of shetland, scotland, in january 1993, many shags (phalacrocorax aristotelis) were killed. sixty-nine per cent of these birds were found to harbor a sexually mature acanthocephalan (5 +/- 4.3 [se] worms per infected bird) in their small intestines. the acanthocephalan has been identified as andracantha tunitae (= corynosoma tunitae) on the basis of its characteristic fields of trunk spines and their distribution in the region of the genit ... | 1995 | 7776143 |
| observations on the subgenus argas (ixodoidea: argasidae: argas). 19. description of the larva of the palearctic cormorant parasite a. (a.) macrostigmatus. | larvae of 19 of the 21 species of the argas subgenus argas are already described. one of the two exceptions is a. (a.) macrostigmatus; we describe the larva of this species from wet nests of the crested cormorant, phalacrocorax aristotelis, from corsica, france. as in the adult and nymphal stages, this larva has an uncovered haller's organ, a character shared in palearctic members of this large genus only with a. (a.) polonicus, a central european parasite of rock pigeons. available larval sampl ... | 1984 | 6470892 |
| global monitoring of persistent organic pollutants (pops) using seabird preen gland oil. | situated at high positions on marine food webs, seabirds accumulate high concentrations of persistent organic pollutants (pops), such as polychlorinated biphenyls (pcbs), dichlorodiphenyltrichloroethane and its metabolites (ddts), and hexachlorocyclohexanes (hchs). our previous studies proposed the usefulness of seabirds preen gland oil as a nondestructive biomonitoring tool. the present study applied this approach to 154 adult birds of 24 species collected from 11 locations during 2005-2016 to ... | 2018 | 30232531 |
| halogenated natural products in birds associated with the marine environment: a review. | halogenated natural products (hnps) are widespread compounds found at high concentrations in top predators such as seabirds. this paper reviews available data on methoxylated polybrominated diphenyl ethers (meo-bdes), heptachloro-1'-methyl-1,2'-bipyrrole (q1) and 1,1'-dimethyl-2,2'-bipyrroles (hdbps) in these animals. in all, 25 papers reported such hnps in seabirds. white tailed sea eagle from sweden was the seabird species with higher meo-bdes levels in eggs and blood, while in liver the europ ... | 2020 | 32062248 |
| social information use and collective foraging in a pursuit diving seabird. | individuals of many species utilise social information whilst making decisions. while many studies have examined social information in making large scale decisions, there is increasing interest in the use of fine scale social cues in groups. by examining the use of these cues and how they alter behaviour, we can gain insights into the adaptive value of group behaviours. we investigated the role of social information in choosing when and where to dive in groups of socially foraging european shags ... | 2019 | 31545848 |
| microplastics in special protected areas for migratory birds in the bay of biscay. | plastic pollution is a major ecological catastrophe that endangers vulnerable species. small plastic fragments and filaments enter the food web in the ocean threatening marine species health. here microplastics between 0.5 and 5 mm were quantified from eight beaches of southwest bay of biscay (spain) within natura-2000 special protection areas for birds. sand samples were taken using a randomized quadrat-based protocol. between 145 and 382 particles per kg of dry sand were found, which is relati ... | 2019 | 31426247 |
| the use of european shag pellets as indicators of microplastic fibers in the marine environment. | microplastic particles are abundant marine pollutants that are ingested by many seabirds. some seabirds regurgitate non-digestible materials in the form of pellets and their analysis may be useful to study the abundance of plastic debris at the local scale. here, we aimed to provide baseline data for the presence of microplastics in pellets regurgitated by european shags (phalacrocorax aristotelis) (n = 41) in the iberia peninsula (nw spain). we found microplastic fibers in 63% of pellets, sugge ... | 2018 | 30503453 |
| parasitism in early life: environmental conditions shape within-brood variation in responses to infection. | parasites play key ecological and evolutionary roles through the costs they impose on their host. in wild populations, the effect of parasitism is likely to vary considerably with environmental conditions, which may affect the availability of resources to hosts for defense. however, the interaction between parasitism and prevailing conditions is rarely quantified. in addition to environmental variation acting on hosts, individuals are likely to vary in their response to parasitism, and the combi ... | 2014 | 25535557 |
| the role of parasitism in the energy management of a free-ranging bird. | parasites often prompt sub-lethal costs to their hosts by eliciting immune responses. these costs can be hard to quantify but are crucial to our understanding of the host's ecology. energy is a fundamental currency to quantify these costs, as energetic trade-offs often exist between key fitness-related processes. daily energy expenditure (dee) comprises of resting metabolic rate (rmr) and energy available for activity, which are linked via the energy management strategy of an organism. parasitis ... | 2018 | 30397174 |
| the energetic cost of parasitism in a wild population. | parasites have profound fitness effects on their hosts, yet these are often sub-lethal, making them difficult to understand and quantify. a principal sub-lethal mechanism that reduces fitness is parasite-induced increase in energetic costs of specific behaviours, potentially resulting in changes to time and energy budgets. however, quantifying the influence of parasites on these costs has not been undertaken in free-living animals. we used accelerometers to estimate energy expenditure on flying, ... | 2018 | 29848646 |
| a new method to quantify prey acquisition in diving seabirds using wing stroke frequency. | to understand the foraging strategies of free-ranging diving animals, time series information on both foraging effort and foraging success is essential. theory suggests that wing stroke frequency for aerial flight should be higher in heavier birds. based on this premise, we developed a new methodology using animal-borne accelerometers to estimate fine-scale temporal changes in body mass of a pursuit-diving, piscivorous seabird, the european shag, phalacrocorax aristotelis. we hypothesized that v ... | 2008 | 18083733 |
| regulation of stroke and glide in a foot-propelled avian diver. | bottom-feeding, breath-hold divers would be expected to minimize transit time between the surface and foraging depth, thus maximizing the opportunities for prey capture during the bottom phase of the dive. to achieve this they can potentially adjust a variety of dive parameters, including dive angle and swim speed. however, because of predictable changes in buoyancy with depth, individuals would also be expected to adjust dive behavior according to dive depth. to test these predictions we deploy ... | 2005 | 15939764 |
| does food shortage delay development of homeothermy in european shag nestlings (phalacrocorax aristotelis)? | nestlings seem to face a trade-off between reducing the basal level of energy metabolism, as an energy-saving response, and maintaining thermogenic capacity during temporal food shortage. in the present study we examined developmental responses to short-term diet restriction of 12-16 day old nestling european shags kept under laboratory conditions and tested whether temporal food shortage delay the development of homeothermy. during food shortage the european shag nestlings substantially reduced ... | 2005 | 15565309 |
| breeding density, fine-scale tracking, and large-scale modeling reveal the regional distribution of four seabird species. | population-level estimates of species' distributions can reveal fundamental ecological processes and facilitate conservation. however, these may be difficult to obtain for mobile species, especially colonial central-place foragers (ccpfs; e.g., bats, corvids, social insects), because it is often impractical to determine the provenance of individuals observed beyond breeding sites. moreover, some ccpfs, especially in the marine realm (e.g., pinnipeds, turtles, and seabirds) are difficult to obser ... | 2017 | 28653410 |
| telomere loss in relation to age and early environment in long-lived birds. | shortening of telomeres, specific nucleotide repeats that cap eukaryotic chromosomes, is thought to play an important role in cellular and organismal senescence. we examined telomere dynamics in two long-lived seabirds, the european shag and the wandering albatross. telomere length in blood cells declines between the chick stage and adulthood in both species. however, among adults, telomere length is not related to age. this is consistent with reports of most telomere loss occurring early in lif ... | 2004 | 15306302 |
| no evidence for fitness signatures consistent with increasing trophic mismatch over 30 years in a population of european shag phalacrocorax aristotelis. | as temperatures rise, timing of reproduction is changing at different rates across trophic levels, potentially resulting in asynchrony between consumers and their resources. the match-mismatch hypothesis (mmh) suggests that trophic asynchrony will have negative impacts on average productivity of consumers. it is also thought to lead to selection on timing of breeding, as the most asynchronous individuals will show the greatest reductions in fitness. using a 30-year individual-level dataset of br ... | 2020 | 33070317 |
| among-individual and within-individual variation in seasonal migration covaries with subsequent reproductive success in a partially migratory bird. | within-individual and among-individual variation in expression of key environmentally sensitive traits, and associated variation in fitness components occurring within and between years, determine the extents of phenotypic plasticity and selection and shape population responses to changing environments. reversible seasonal migration is one key trait that directly mediates spatial escape from seasonally deteriorating environments, causing spatio-seasonal population dynamics. yet, within-individua ... | 2020 | 32693718 |
| interactions between environmental contaminants and gastrointestinal parasites: novel insights from an integrative approach in a marine predator. | environmental contaminants and parasites are ubiquitous stressors that can affect animal physiology and derive from similar dietary sources (co-exposure). to unravel their interactions in wildlife, it is thus essential to quantify their concurring drivers. here, the relationship between blood contaminant residues (11 trace elements and 17 perfluoroalkyl substances) and nonlethally quantified gastrointestinal parasite loads was tested while accounting for intrinsic (sex, age, and mass) and extrin ... | 2020 | 32551599 |
| complex demographic heterogeneity from anthropogenic impacts in a coastal marine predator. | environmental drivers, including anthropogenic impacts, affect vital rates of organisms. nevertheless, the influence of these drivers may depend on the physical features of the habitat and how they affect life history strategies depending on individual covariates such as age and sex. here, the long-term monitoring (1994-2014) of marked european shags in eight colonies in two regions with different ecological features, such as foraging habitat, allowed us to test several biological hypotheses abo ... | 2018 | 29297945 |
| avian diving, respiratory physiology and the marginal value theorem. | behavioural studies of diving birds have reported that the ratio of dive duration to the duration of the subsequent period on the surface displays a characteristic relation to dive duration. for short dives, the dive to surface ratio increases with dive duration, whereafter the relation peaks, and for longer dives decreases with increasing dive duration. such a relationship is not a general prediction of existing marginal value models which have been used to predict optimal diving behaviour. thi ... | 1998 | 9710474 |
| comparing marine distribution maps for seabirds during the breeding season derived from different survey and analysis methods. | understanding how seabirds use the marine environment is key for marine spatial planning, and maps of their marine distributions derived from transect-based surveys and from tracking of individual bird's movements are increasingly available for the same geographic areas. although the value of integrating these different datasets is well recognised, few studies have undertaken quantitative comparisons of the resulting distributions. here we take advantage of four existing distribution maps and co ... | 2018 | 30157191 |
| mercury exposure in birds linked to marine ecosystems in the western mediterranean. | mercury (hg), particularly as methylmercury (mehg), is a nonessential, persistent, and bioaccumulative toxic element with high biomagnification capacity and is considered a threat to marine environments. we evaluated total hg concentrations in liver, kidney, and brain in 62 individuals of 9 bird species linked to marine ecosystems from western mediterranean admitted in a wildlife rehabilitation center (wrc) (alicante, spain, 2005-2020). age- and sex-related differences in hg levels, as well as t ... | 2020 | 33106911 |