Análisis de las recuperaciones de Gaviota Tridáctila (Rissa tridactyla) en la Península Ibérica

S'estudien les recuperacions de gavineta de tres dits a la península Ibèrica a partir de l'anàlisi de les dades d'Espanya i Portugal. Un percentatge important de les recuperacions 60,9% (n=41) es produeixen al golf de Biscaia; la majoria de les recuperacions són d'ocells juvenils i es produeixen en el període novembre-gener. En aquesta àrea una part dels ocells moren a causa de les xarxes de pesca i caça. Al llarg de la costa atlàntica 11 recuperacions indicaren dispersió més enllà del golf de Biscaia, mentre que a la costa mediterrània només s'han produït quatre recuperacions. Al voltant d'un 80% de les recuperacions són d'ocells britànics amb un nombre important de gavines procedents de la colònia de les illes Farne

Benefits and costs of parental care

This chapter summarizes important advances in the understanding of the mechanisms underlying the costs and benefits of parental care. It starts by analysing the nature of parental resources, addressing also the possibility of cost-free resources. It then reviews short and long-term benefits of parental care and how parents adjust offspring phenotypes to attain such benefits. Similarly, it reviews physiological and non-physiological costs of parental care and the current support for a link with fitness. It concludes that, despite important recent advances, the integration of proximate mechanisms into ultimate explanations is still far from successful.Peer Reviewe

Population modelling of European shags ("Phalacrocorax aristotelis") at their southern limit: conservation implications

The European shag ("Phalacrocorax aristotelis") population at Cíes Islands (the most important breeding area in its southern limit) increased rapidly from 1986 to 1992, and afterwards the population suffered a slight decline. This study analyzed population data obtained from ringing recoveries and reproductive monitoring between 1993 and 1997. The reproductive success was highly variable and associated with adverse weather events. Adult survival rate was very low compared with other colonies, probably due to high accidental capture in gill-nets. In recent years, the fishing effort with gill-nets increased in the study area. Sensitivity analysis of parameters showed that the population is more affected by changes in adult survival than in reproductive success. When dynamic simulations were run with an increase in shag mortality of 5% above the present level, population extinction occurred in all simulations. In contrast, when a reduction of mortality of 5% was introduced in the simulations, the population increased in all cases. The main lines of action to study and protect this population should be: (1) ringing schemes to obtain better estimates of survival variability; (2) studies on the interaction of feeding areas and fishing vessels; (3) regulations on gill-netting; and (4) the incorporation of population models as an adaptive management tool to synthesize assessment work and management scenario

Colony Foundation in an Oceanic Seabird

Seabirds are colonial vertebrates that despite their great potential for long-range dispersal and colonization are reluctant to establish in novel locations, often recruiting close to their natal colony. The foundation of colonies is therefore a rare event in most seabird species and little is known about the colonization process in this group. The Cory’s shearwater (Calonectris diomedea) is a pelagic seabird that has recently established three new colonies in Galicia (NE Atlantic) thus expanding its distribution range 500 km northwards. This study aimed to describe the establishment and early progress of the new Galician populations and to determine the genetic and morphometric characteristics of the individuals participating in these foundation events. Using 10 microsatellite loci, we tested the predictions supported by different seabird colonization models. Possibly three groups of non-breeders, adding up to around 200 birds, started visiting the Galician colonies in the mid 2000’s and some of them eventually laid eggs and reproduced, thus establishing new breeding colonies. The Galician populations showed a high genetic diversity and a frequency of private alleles similar to or even higher than some of the large historical populations. Most individuals were assigned to several Atlantic populations and a few (if any) to Mediterranean colonies. Our study suggests that a large and admixed population is settling in Galicia, in agreement with predictions from island metapopulation models of colonization. Multiple source colonies imply that some birds colonizing Galicia were dispersing from very distant colonies (> 1500 km). Long-distance colonizations undertaken by relatively large and admixed groups of colonizers can help to explain the low levels of genetic structure over vast areas that are characteristic of most oceanic seabird speciesThis study was funded annually (2010–2013) by the Organismo Autónomo de Parques Nacionales of Spain (http://www.magrama.gob.es/es/parques-nacionales-oapn/programa-investigacion/) through the research project 079/2009. Financial support for the fieldwork in Azores, Madeira, Selvagens and Berlengas was provided by the EU project LIFE04NAT/PT/000213, coordinated by SPEA (Sociedade Portuguesa para o Estudo das Aves), the BirdLife International partner in Portugal. HP acknowledges the support given by the Fundação para a Ciência e Tecnologia (Portugal, SFRH/BD/21557/2005 and SFRH/BPD/85024/2012). Financial support for the fieldwork in Cima Islet was provided by the EU project LIFE09NAT/PT/000041. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Santiago Barciela, Álvaro Barros, Paula Domínguez and David Álvarez were contracted for field data collection in GaliciaS

Parental Age and Lifespan Influence Offspring Recruitment: A Long-Term Study in a Seabird

Recent studies of wild populations provide compelling evidence that survival and reproduction decrease with age because of senescence, a decline in functional capacities at old ages. However, in the wild, little is known about effects of parental senescence on offspring quality. We used data from a 21-year study to examine the role of parental age on offspring probability of recruitment in a long-lived bird, the blue-footed booby (Sula nebouxii). Offspring probability of recruiting into the breeding population varied over the life of parents and effects age were similar in mothers and fathers. Offspring recruitment was high when parents were roughly 6–12 years old and low before and after then. Effects of parental age on offspring recruitment varied with lifespan (parental age at last reproduction) and previous breeding experience. Offspring recruitment from young and old parents with long reproductive lifespans was greater than that of offspring from parents with short lifespans at young and old ages. For parents with little previous breeding experience recruitment of offspring decreased with their hatch date, but experienced parents were no similarly affected. We found evidence of terminal effects on offspring recruitment in young parents but not in older parents, suggesting that senescence is more likely a gradual process of deterioration than a process of terminal illness. Failure to recruit probably reflects mortality during the first years after independence but also during the fledgling transition to full independence. Our results show effects of parental age and quality on offspring viability in a long-lived wild vertebrate and support the idea that wild populations are composed of individuals of different quality, and that this individual heterogeneity can influence the dynamics of age-structured populations

Changes in plasma biochemistry and body mass during incubation in the Yellow-legged Gull

The >Incubatory Reserves Constancy> hypothesis asserts that incubation could be a departure from breeding stress that allows for the maintenance or recovery of body reserves after laying effort (females) or territory defense (males) in those species with bi-parental incubation such as gulls. The plasma composition and body mass of incubating Yellow-legged Gulls (Larus cachinnans) were analyzed and related to the number of days after egg-laying. Female gulls showed an increase in uric acid and cholesterol levels, whereas males showed only an increase in uric acid values throughout this period. Moreover, females increased while males maintained their body masses. These results could reflect a recovery process after the laying effort supporting the Incubatory Reserves Constancy hypothesis in females. Uric acid and urea levels are positively correlated to body condition in Yellow-legged Gulls, which could be the result of a change in diet composition. This disagrees with recent findings on body composition in incubating gulls and could be related to variations in food availability among populations or years, and could reflect flexibility in the investment devoted by each sex.Peer Reviewe

Light received by embryos promotes postnatal junior phenotypes in a seabird

Light is a salient and variable ecological factor that can impact developmental trajectories of vertebrate embryos, yet whether prenatal light environment can act as an anticipatory cue preparing organisms to cope with postnatal conditions is still unclear. In asynchronous birds, last-laid eggs are particularly exposed to sunlight as parental incubation behavior becomes intermittent after the hatching of senior chicks. Here, we explore whether natural variations in prenatal light exposure shape the distinctive phenotype showed by last-hatched chicks of a semi-precocial seabird, the yellow-legged gull (Larus michahellis), potentially preparing them to cope with the postnatal competitive context. To do this, we manipulated the amount of light received by last-laid eggs (within a natural range) during last stages of embryonic development. Prenatal exposure to light cues promoted the development of the resilient “junior phenotype” exhibited by last-hatched gull chicks, characterized by accelerated hatching, increased begging behavior and a slower growth rate. These developmental and behavioral adjustments were accompanied by down-regulation of genes involved in metabolism and development regulation (SOD2 and TRalpha), as well as changes in the HPA-axis functioning (lower baseline corticosterone and robust adrenocortical response). Junior chicks exposed to light cues during the embryonic development showed longer telomeres during the early postnatal period, suggesting that light-induced adjustments could allow them to buffer the competitive disadvantages associated with hatching asynchrony. Our study provides evidence that postnatal junior phenotypes are, at least in part, prenatally shaped by light cues that act during a critical temporal window of developmental sensitivity.Agencia Estatal de Investigación | Ref. PGC2018-095412-B-I00Agencia Estatal de Investigación | Ref. FJC2018-037157-

Redox-regulation and life-history trade-offs: scavenging mitochondrial ROS improves growth in a wild bird

It has been proposed that animals usually restrain their growth because fast growth leads to an increased production of mitochondrial reactive oxygen species (mtROS), which can damage mitochondrial DNA and promote mitochondrial dysfunction. Here, we explicitly test whether this occurs in a wild bird by supplementing chicks with a mitochondria-targeted ROS scavenger, mitoubiquinone (mitoQ), and examining growth rates and mtDNA damage. In the yellow-legged gull Larus michahellis, mitoQ supplementation increased the early growth rate of chicks but did not reduce mtDNA damage. The level of mtDNA damage was negatively correlated with chick mass, but this relationship was not affected by the mitoQ treatment. We also found that chick growth was positively correlated with both mtDNA copy number and the mitochondrial enzymatic activity of citrate synthase, suggesting a link between mitochondrial content and growth. Additionally, we found that MitoQ supplementation increased mitochondrial content (in males), altered the relationship between mtDNA copy number and damage, and downregulated some transcriptional pathways related to cell rejuvenation, suggesting that scavenging mtROS during development enhanced growth rates but at the expense of cellular turnover. Our study confirms the central role of mitochondria modulating life-history trade-offs during development by other mechanisms than mtROS-inflicted damage.Ministerio de Economía y Competitividad | Ref. CGL2015-69338-C2-1-

Glucocorticoids modulate gastrointestinal microbiome in a wild bird.

It has recently been hypothesized that stress exposure (e.g. via glucocorticoid secretion) may dysregulate the bacterial gut microbiome, a crucial \u27organ\u27 in animal health. However, whether stress exposure (e.g. via glucocorticoid secretion) affects the bacterial gut microbiome of natural populations is unknown. We have experimentally altered the basal glucocorticoid level (corticosterone implants) in a wild avian species, the yellow-legged gul

Maternal effect senescence via reduced DNA repair ability in the three‐spined stickleback

Maternal effect senescence, a decline in offspring viability with maternal age, has been documented across diverse animals, but its mechanisms remain largely unknown. Here, we test maternal effect senescence and explore its possible molecular mechanisms in a fish. We compared the levels of maternal mRNA transcripts of DNA repair genes and mtDNA copies in eggs and the levels of DNA damage in somatic and germline tissues between young and old female sticklebacks. We also tested, in an in vitro fertilization experiment, whether maternal age and sperm DNA damage level interactively influence the expression of DNA repair genes in early embryos. Old females transferred less mRNA transcripts of DNA repair genes into their eggs than did young females, but maternal age did not influence egg mtDNA density. Despite a higher level of oxidative DNA damage in the skeletal muscle, old females had a similar level of damage in the gonad to young females, suggesting the prioritization for germline maintenance during ageing. The embryos of both old and young mothers increased the expression of DNA repair genes in response to an increased level of oxidative DNA damage in sperm used for their fertilization. The offspring of old mothers showed higher rates of hatching, morphological deformity and post‐hatching mortality and had smaller body size at maturity. These results suggest that maternal effect senescence may be mediated by reduced capacity of eggs to detect and repair DNA damages, especially prior to the embryonic genomic activation.Agencia Estatal de Investigación | Ref. PGC2018-095412-B-I00Universidade de Vigo/CISU