Raül Ramos

University of Barcelona | UB · Department of Evolutionary Biology, Ecology and Environmental Sciences

The conservation status and taxonomy of the three gadfly petrels that breed in Macaronesia is still discussed partly due to the scarce information on their spatial ecology. Using geolocator and capture-mark-recapture data, we examined phenology, natal philopatry and breeding-site fidelity, year-round distribution, habitat usage and at-sea activity...

Human activities have serious impacts on marine apex predators. Inadequate knowledge of the spatial and trophic ecology of these marine animals ultimately compromises the viability of their populations and impedes our ability to use them as environmental biomonitors. Intrinsic biogeochemical markers, such as stable isotopes, fatty acids, trace elem...

Aim Apical pelagic species forage in predictable habitats, and their movements should signal biologically and ecologically significant areas of the marine ecosystem. Several countries are now engaged in identifying these areas based on animal tracking, but this is often limited to a few individuals from one breeding population, which may result in...

Aim Our current understanding of migratory strategies and the reasons for their high variability along the phylogenetic tree remains relatively poor. Most of the hypotheses relating to migration have been formulated for terrestrial taxa; classically, oceanic migrations were considered as merely dispersive because of the scarcity of observations in...

Although little studied in natural populations, the persistence of immunoglobulins may dramatically affect the dynamics of immunity and the ecology and evolution of host-pathogen interactions involving vertebrate hosts. By means of a multiple-year vaccination design against Newcastle disease virus, we experimentally addressed whether levels of spec...

For vulnerable and endangered migratory species, an important and often overlooked aspect of conservation is their non-breeding distributions. For long-lived species, an additional constraint is the lack of data on juvenile movements. Individual relationships between age, movement ecology, and habitat preference for long-lived migratory birds remai...

Relationships between individual's age and the movement ecology and habitat preference of long-lived migratory birds still remain understudied. According to the exploration-refinement hypothesis it is thought that adults would select better and more productive areas for foraging than inexperienced juvenile birds would do. Additionally, age-related...

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are h...

La reproducción y la migración son dos procesos cruciales en el ciclo anual de cualquier especie migratoria, ya que ambos suponen una alta inversión energética. En especies longevas, como las aves marinas, ambos procesos están estrechamente relacionados de forma que pueden interaccionar entre sí, es decir, lo que ocurre en una etapa puede afectar a...

Aim Over the last decades, the study of movement through tracking data has grown exceeding the expectations of movement ecologists. This has posed new challenges, specifically when using individual tracking data to infer higher‐level distributions (e.g. population and species). Sources of variability such as individual site fidelity (ISF), environm...

Climate change has repeatedly been shown to impact the demography and survival of marine top predators. However, most evidence comes from single populations of widely distributed species, limited mainly to polar and subpolar environments. Here, we aimed to evaluate the influence of environmental conditions on the survival of a tropical and migrator...

Determining the non‐breeding distribution and activity patterns of migratory animals is essential to understand the trade‐offs across breeding, moulting and migratory periods and to evaluate the differential levels of exposure of these animals to threats throughout the year. By taking advantage of the current miniaturisation of geolocators, during...

In colonial seabirds, ecological divergence may occur in the absence of physical barriers, driven by the isolation of populations due to distance, or the adaptation to local environment. In migratory seabirds, the geographic segregation among breeding populations can persist year round (i.e., strong migratory connectivity) when populations breeding...

For centuries, human activities have altered the population dynamics of wildlife. New anthropogenic food sources provide a predictable and abundant food supply that often induces very significant changes in the size, distribution, and behaviour of many populations, with ultimate consequences on the structure and functioning of natural ecosystems. H...

Light‐level geolocators are popular bio‐logging tools, with advantageous sizes, longevity and affordability. Biologists tracking seabirds often presume geolocator spatial accuracies between 186 and 202 km from previously innovative, yet taxonomically, spatially and computationally limited, studies. Using recently developed methods, we investigated...

The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population da...

Costs of reproduction on survival have captured the attention of researchers since life history theory was formulated. Adults of long-lived species may increase survival by reducing their breeding effort or even skipping reproduction. In this study, we aimed to evaluate the costs of current reproduction on survival and whether skipping reproduction...

Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of nation...

Sexual segregation in foraging strategies has been little studied in marine species with slight sexual size dimorphism (SSD), particularly regarding the role of environmental conditions and fishery activities. Sexual differences in fishery attendance are of particular concern because uneven mortality associated with bycatch may exacerbate impacts i...

Las actividades pesqueras y acuícolas representan uno de los mayores impactos antropogénicos sobre los ecosistemas marinos. En España, durante la pasada década, se creó una amplia Red de Áreas Marinas Protegidas (RAMPE) para minimizar dicho impacto; sin embargo, su eficacia todavía está por determinar. Aquí evaluamos el papel de la actual RAMPE en...

Seabirds inhabiting vast water masses provide numerous examples where opposing phenomena, such as natal and breeding philopatry vs. vagility have dug cryptic taxonomic boundaries among closely related taxa. The taxonomy of little shearwaters of the North Atlantic Ocean (Little–Audubon’s shearwater complex, Puffinus assimilis–lherminieri) still rema...

Despite its importance for ecology and conservation, we are still far from understanding how environmental variability interacts with intrinsic factors and individual specialization to determine trophic strategies of long-lived taxa, mostly due to difficulties in studying the same animals over extended periods. Here, by yearly consistently sampling...

ABSTRACT: Insights into the year-round movements and behaviour of seabirds are essential to better understand their ecology and to evaluate possible threats at sea. The Atlantic petrel Pterodroma incerta is an Endangered gadfly petrel endemic to the South Atlantic Ocean, with virtually the entire population breeding on Gough Island (Tristan da Cun...

In the present publication we analyzed the migration and foraging ecology of Bulwer’s petrel (Bulweria bulwerii) in one locality at Canary Islands, based in the results obtained by the University of Barcelona in the framework of different research and conservation seabird projects. This monograph describes the foraging ecology and the year-round...

Sexual segregation (SS) is widespread among animal taxa, with males and females segregated in distribution, behavior, or feeding ecology but so far, most studies on birds have focused on the breeding period. Outside this period, the relevance of segregation and the potential drivers of its persistence remain elusive, especially in the marine enviro...

In the past few decades, several species of gulls have increased their population dramatically. Among these, the yellow-legged gull (Larus michahellis) has become a serious public health problem because they are carriers of zoonotic bacteria such as Campylobacter spp. and interact with human populations. These gulls present wide feeding plasticity...

Many generalist species are composed of individuals varying in the size of their realized niches within a population. To understand the underlying causes and implications of this phenomenon, repeated samplings on the same individuals subjected to different environmental conditions are needed. Here, we studied individual specialization of feeding st...

Using geolocator-immersion loggers, we tracked for the first time the migration of one Cory’s Shearwater Calonectris borealis fledgling, from its breeding colony in the Canary Islands, and along its first year of life. The juvenile bird initially followed the same migratory path as the adults but visited different areas of the Central and the South...

Non-breeding movement strategies of migratory birds may be expected to be flexibly adjusted to the distribution and quality of habitat, but few studies compare movement strategies among populations using distinct migration routes and wintering areas. In our study, individual movement strategies of red-necked phalaropes (Phalaropus lobatus), a long-...

Variability in long‐distance migration strategies is still poorly understood due to the fact that individuals are often tracked from a single colony/population. Transoceanic migrations of Scopoli's shearwaters (Calonectris diomedea) across the Strait of Gibraltar (SoG) have been tracked from several breeding colonies isolatedly, and factors related...

Shearwaters and petrels (hereafter petrels) are highly adapted seabirds that occur across all the world’s oceans. Petrels are a threatened seabird group comprising 124 species. They have bet-hedging life histories typified by extended chick rearing periods, low fecundity, high adult survival, strong philopatry, monogamy and long-term mate fidelity...

Efficiently tracking and anticipating the dynamics of infectious agents in wild populations requires the gathering of large numbers of samples, if possible at several locations and points in time, which can be a challenge for some species. Testing for the presence of specific maternal antibodies in egg yolks sampled on the colonies could represent...

In predator populations, changes in foraging behaviour in response to spatio-temporal variability of prey are expected. Prey depletion might cause trophic niche widening in generalist species, but not in specialists, which are expected to increase their foraging effort without diet shifts. In sympatric species feeding on similar resources, reduced...

Foraging distributions of colonial central place foragers are shaped not only by environmental factors but also by population parameters: larger colonies will deplete resources around the colony and will therefore have larger foraging areas, but parapatric competition will often cause spatial segregation, leading to little overlap among foraging ar...

Life history theory states that individual fitness in one stage of life is conditioned by what occurred in previous stages. In migratory species, reproductive effort during breeding has often been found to influence body condition, molt schedule, self‐provisioning and migration of individuals in subsequent seasons (i.e., carryover effects of breedi...

Studying the movements of oceanic migrants has been elusive until the advent of several tracking devices, such as the light-level geolocators. Stable isotope analysis (SIA) offers a complementary approach to infer areas used year-round, but its suitability in oceanic environments remains almost unexplored. To evaluate SIA as a tool for inferring mo...

Total number of GLS loggers deployed and recovered by colony, and number of GLS loggers included in the present study. Only GLS loggers with data for the last non-breeding period before recovering were included in this study, in order to relate the non-breeding areas with the feathers moulted during the non-breeding period and sampled at GLS logger...

Biplots of δ15N and δ13C values for P1 (a), S8 (b) and R6 (c) feathers sampled from tracked individuals of Bulwer’s petrel. In each plot, we show isotopic values and Standard Bayesian Ellipses by non-breeding areas (depicted in triangles and discontinuous contours for birds wintering in the Central Atlantic, and in circles and continuous contours f...

Accepted values of the standard material used in the stable isotopic analysis performed in this study, mean measured (±standard deviation) in the samples of standards materials used, minimum and maximum values for all runs, and number of samples (n). (DOCX)

Boxplots of δ15N (a) and δ13C (b) values for the 1st (P1), 3rd (P3), 5th (P5), 7th (P7) and 10th (P10) primary feathers, the 1st (S1), 12th (S12) and 8th (S8) secondary feathers of Bulwer’s petrels found dead at each colony: Vila (in blue, n = 8), M. Clara (green, n = 8), Raso (orange, n = 9) and Cima (red, n = 4). The 6th rectrix (R6) of corpses a...

Isotopic data of corpses and tracked Bulwer’s petrels included in the article. (DOCX)

Reproductive timing in many taxa plays a key role in determining breeding productivity ¹, and is often sensitive to climatic conditions ² . Current climate change may alter the timing of breeding at different rates across trophic levels, potentially resulting in temporal mismatch between the resource requirements of predators and their prey ³ . Thi...

This book has been published by the Spanish Society of Ornithology (SEO/BirdLife) in the framework of the MIGRA programme. In this work we analyse the movement ecology and at-sea behaviour of two related seabird species under conservation concern: the Scopoli's and the Cory's Shearwater. It focuses on Spanish populations, covering the entire distri...

1. Many studies in disease and immunological ecology rely on the use of assays that quantify the amount of specific antibodies (immunoglobulin) in samples. Enzyme-Linked Immuno Sorbent Assays (ELISAs) are increasingly used in ecology due to their availability for a broad array of antigens and the limited amount of sampling material they require. Tw...

La dieta y las áreas de alimentación son aspectos básicos de la ecología de cualquier especie, y conocerlos es imprescindible para su adecuado manejo y conservación. Sin embargo, sólo con los avances tecnológicos recientes, es posible abordarlos en aves marinas de pequeño porte como el petrel de Bulwer (Bulweria bulwerii). De 2015 a 2017 en Montaña...

Many studies in disease and ecological immunology rely on the use of assays that quantify the amount of specific antibodies (immunoglobulin) in samples. Enzyme‐linked immunosorbent assays ( ELISA s) are increasingly used in ecology due to their availability for a broad array of antigens and the limited amount of sampling material they require. Two...

Aim: Anthropogenic activities alter and constrain the structure of marine ecosystems with implications for wide-ranging marine vertebrates. In spite of the environmental importance of vast oceanic ecosystems, most conservation efforts mainly focus on neritic areas. To identify relevant oceanic areas for conservation, we assessed the year-round spat...

Conservation policies for the protection of marine biodiversity are being implemented in many international management treaties worldwide. The process of identification of Marine Protected Areas (MPAs) is often based on the spatial preference of threatened species, such as many marine predators. Multi-colony tracking studies comprising a wide geogr...

Wildlife is a natural reservoir of Salmonella and Campylobacter, the most important human foodborne pathogens worldwide. Free-living birds have the potential to transport, over large distances, such zoonotic bacteria that may harbor antimicrobial resistance traits. On the northeastern Iberian coast, we assessed the role of Yellow-legged Gulls ( Lar...

It is well known that colonial breeders are spatially constrained by their need to return to the colony to attend their rearing duties. This behaviour results in a decreasing density of foraging birds with the distance to the colony. In addition, the effect of intraspecific competition, which grows with colony size, also increases the length of for...

Geolocators are revealing new aspects of seabird migratory dynamics, but its price and size and some constraints about bird recapture limit their use. Alternatively, stable isotope analysis (SIA) on feathers may allow inferring non-breeding distributions of seabirds, but its suitability in tropical and subtropical species remains unexplored. Here,...

Geolocators are revealing new aspects of the migratory dynamics of seabirds, but due to price, size, or limitations in recapturing birds, geolocators are not always feasible to use. In this regard, stable isotope analyses (SIA) on feathers have emerged as an alternative tool to infer their non-breeding areas. In the marine environment, the majority...

Research on sexual segregation is essential to understand the role of sexual differences on distribution, migration and reproduction over the annual cycle of migratory species. Sexual differences in seabird ecology have been often reported during the breeding period, yet little is known about sex effects out of that period. We evaluated the degree...

Foraging strategies of colonial central-place foragers, such as breading seabirds, are spatially constrained by their need to return to the colony to attend to their rearing duties and by a denso-dependent competition for resources that increases with colony size. Moreover, in areas where the foraging ranges of several breeding colonies potentially...

Long-distance dispersal events and their derivable increases of genetic diversity have been highlighted as important ecological and evolutionary determinants that improve performances of range-expanding species. In the context of global environmental change, specific dispersal strategies have to be understood and foreseen if we like to prevent gene...

Chemical signals may be the basis of interspecific recognition and speciation in many animals. To test whether a chemical label allowing recognition between closely related species exists in seabirds, we investigated two closely related taxa breeding sympatrically at some localities: Cory's and Scopoli's shearwaters. Procellariiform seabirds are id...

In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Medit...