This dataset was used to analyze survival probabilities of adult Audouin’s gull depending on early conditions (density-dependence and Winter NAO) experienced by the individuals., Capture mark recapture data of Audouin gulls breeding from 1995 until 2009 in Mediterranean locations including Ebro Delta, Chafarinas Islands,
Columbretes Islands and Mallorca islets in the Balearic Islands. Individuals are shown in rows and years in columns followed by the cohort on which they were born, and the environmental covariates associated to that year. This data set has been used for the publication: Payo-Payo, A.; Sanz-Aguilar, A. and Oro, D. (2022) Long-lasting effects of harsh early-life conditions on adult survival of a long-lived vertebrate. OIKOS., We acknowledge financial support through projects RESET (CGL2017-85210-P), IBISES (ref. CGL2013-42203-R) and MINOW (ref. H2020- 634495)., This work was funded through projects RESET (CGL2017-85210-P) and IBISES (ref. CGL2013-42203-R).
APP was supported by a predoctoral fellowship of the Ministry of Education (FPU-AP 2012-0869).
ASA is supported by a postdoctoral contract co-funded by the Regional Government of the Balearic Islands and the European Social Fund (ref. PD/003/2016) and a Ramón y Cajal fellowship ( Ref. RYC-2017- 22796)., The data file contains resight histories of Audouin’s gulls born at Ebro Delta and observed during breeding seasons 1995 to 2009. This file contains one line per individual; one column per encounter occasion (from column 1 to 15 were code 1 indicate resight at Ebro Delta colony and code 2 resight at other colony); one line indicating the number of individual capture histories (column 16); and three further columns indicating the standardized values of early life individual covariates (columns 17, 18, and 19; for DD, WNAO, and DD*WNAO, respectively)., No

Disentangling the influence of demographic parameters and the role of density dependence on species’ population dynamics may be challenging, especially when there are fractions of the population that are unobservable (e.g. dispersers, non-breeders). Additionally, due to the difficulty of gathering data at large spatial scales, most studies ignore the global dynamic of a species, which would integrate heterogeneity in local dynamics and remove the noise of dispersal. We developed a global scale, integrated population model (IPM), to disentangle the main demographic drivers of population dynamics in a long-lived colonial seabird. We used 28 years of Audouin’s gull demographic data encompassing 69 local patches (90% of the world population). Importantly, we took into account the unobservable fraction of non-breeders and also assessed the strength of density dependence for this fraction of the population. As predicted by life histories of long-lived organisms, temporal random variation in survival was highest for immatures (), and lowest for adults (). Large temporal fluctuations in the probability of taking a sabbatical from reproduction would partly explain constancy in adult survival, adults probably refraining from breeding when environmental conditions were harsh. Thus, skipping breeding would be a bet hedging strategy for long-lived organisms having many reproductive chances during their lifespan. Immature survival and fertility were the main drivers of population dynamics during the study period (r2= 0.83 (0.77-0.87) and 0.73 (0.63-0.79) respectively). We found strong evidence of density dependence, not only due to the number of breeders (r2= -0.34 (-0.43 -0.24)) but also to that of sabbaticals (r2= -0.18 (-0.33 -0.01)). Even though population dynamics of long-lived organisms are very sensitive to changes in adult survival, we show here that in the absence of strong environmental perturbations affecting this life history trait, fluctuations in population density in those species may be driven by variations of immature survival and fertility. The species is showing a 5% of annual global decrease during the last ten years, and we propose an updated species conservation status. Integrated models based on long term monitoring at a global scale may enhance our ecological and evolutionary understanding of how demographic drivers influence population dynamics., No

Disentangling the influence of demographic parameters and the role of density dependence on species’ population dynamics may be challenging, especially when there are fractions of the population that are unobservable (e.g. dispersers, non-breeders). Additionally, due to the difficulty of gathering data at large spatial scales, most studies ignore the global dynamic of a species, which would integrate heterogeneity in local dynamics and remove the noise of dispersal. We developed a global scale, integrated population model (IPM), to disentangle the main demographic drivers of population dynamics in a long-lived colonial seabird. We used 28 years of Audouin’s gull demographic data encompassing 69 local patches (90% of the world population). Importantly, we took into account the unobservable fraction of non-breeders and also assessed the strength of density dependence for this fraction of the population. As predicted by life histories of long-lived organisms, temporal random variation in survival was highest for immatures (), and lowest for adults (). Large temporal fluctuations in the probability of taking a sabbatical from reproduction would partly explain constancy in adult survival, adults probably refraining from breeding when environmental conditions were harsh. Thus, skipping breeding would be a bet hedging strategy for long-lived organisms having many reproductive chances during their lifespan. Immature survival and fertility were the main drivers of population dynamics during the study period (r2= 0.83 (0.77-0.87) and 0.73 (0.63-0.79) respectively). We found strong evidence of density dependence, not only due to the number of breeders (r2= -0.34 (-0.43 -0.24)) but also to that of sabbaticals (r2= -0.18 (-0.33 -0.01)). Even though population dynamics of long-lived organisms are very sensitive to changes in adult survival, we show here that in the absence of strong environmental perturbations affecting this life history trait, fluctuations in population density in those species may be driven by variations of immature survival and fertility. The species is showing a 5% of annual global decrease during the last ten years, and we propose an updated species conservation status. Integrated models based on long term monitoring at a global scale may enhance our ecological and evolutionary understanding of how demographic drivers influence population dynamics., M. Genovart is supported by a postdoctoral contract co‐funded by the Regional Government of the Balearic Islands and the European Social Fund. Funds were partially provided by the Spanish Ministry of Economy (ref. CGL2013‐42203‐R and CGL2017‐85210‐P) and the European Union (H2020 RIA‐ MINOUW Grant, ref. H2020‐ 634495)., Peer reviewed

Data are organized in three independent files. (1) Breeding_parameters_Espartar_2014_2018.csv records the reproductive parameters (hatching success (HS), fledgling success (FS) and breeding success (BS)) of all accessible nests of storm petrels at s’Espartar islet (Ibiza, Balearic Islands) during breeding seasons 2014 to 2018. First columns correspond to year (2014 to 2018), colony, nest number and zone of the study nests. Zone was coded as “C” = Chambers and “E” = Entrance. Last three columns (F, G and H) gather reproductive parameters HS, FS and BS being 0 if fails and 1 if successful. (2) Data_nestlings_BC_ticks_Espartar_2018.csv contains the state, the number of ticks attached to nestlings, their maximum number, biometric measurements and the estimated age of nestlings of storm petrels at s’Espartar (Ibiza, Balearic Islands) during breeding season in 2018. This file may contain more than one record (line) per individual because some nestlings were inspected multiple times. First column indicates the zone of the nest (“C” = Chambers and “E” = Entrance), next column corresponds to the nest number (= nestling number) followed by state and the state of the next inspection (state_t+1) of the nestling; these columns indicate if nestling is alive or dead. Columns F and G correspond to the number of ticks in each inspection and the maximum number of ticks found among all inspections respectively; last columns are the measurements of the wing length (mm), tarsus (mm), body mass (g) and estimated age of each nestling inspection. (3) Data_Adults_Espartar2018.csv contains the information about breeding adults of storm petrels from the entrance and chambers of the s’Espartar cave (Ibiza, Balearic Islands) during the breeding season in 2018. This file contains one line per individual being the first column the date of inspection, followed by the zone of the nest, the number of nest, and the ring code of the each individual; and the last three columns (E, F, G) correspond to the biometric measurements of tarsus, wing length and body mass (weight). Missing values in all datasets were coded as “NA”., Dataset (1) was used to analyze reproductive parameters of Storm petrels at S’Espartar islet (Ibiza, Balearic Islands) from 2014 to 2018. Dataset (2) was used to study the number of ticks (tick load) attached on nestlings and how affect them to their body condition depending on the zone where they are found during the breeding season in 2018. Dataset (3) was used to study if exists differences between adults of the different zones of the study area during the breeding season in 2018., This project was partially funded by the Govern Balear (Acciones Especiales, AAEE031/2017) and the Spanish Ministry of innovation and Universities (RESET, ref: CGL2017-85210-P)., No

Ticks can negatively affect their host by direct effects as blood feeding causing anaemia or discomfort, or by pathogen transmission. Consequently, ticks can have an important role in the population dynamics of their hosts. However, specific studies on the demographic effects of tick infestation on seabirds are still scarce. Seabird ticks have also the potential to be responsible for the circulation of little known tick-borne agents, which could have implications for non-seabird species. Here, we report the results of investigations on potential associations between soft tick Ornithodoros maritimus load and reproductive parameters of storm petrels Hydrobates pelagicus breeding in a large colony in a cave of Espartar Island, in the Balearic archipelago. We also investigated by molecular analyses the potential viral and bacterial pathogens associated with O. maritimus ticks present at the colony. Lower nestling survival was recorded in the most infested area, deep in the cave, compared to the area near the entrance. The parasite load was negatively associated with the body condition of the nestlings. One pool of ticks tested positive for West Nile virus and 4 pools tested positive for a Borrelia species which was determined by targeted nested PCR to have a 99% sequence identity with B. turicatae, a relapsing fever Borrelia. Overall, these results show that further investigations are needed to better understand the ecology and epidemiology of the interactions between ticks, pathogens and Procellariiform species., This Project was partially funded by the Govern Balear (Acciones Especiales, AAEE031/2017) and the Spanish Ministry of Innovation and Universities (RESET, ref: CGL2017-85210-P). ASA was funded by the Spanish Ministry of Innovation and Universities Innovation and Universities, the Agencia Estatal de Investigación and the European Social Found (RYC-2017- 22796)., Peer reviewed

Identifying important foraging areas is fundamental to detecting the demographic drivers of a species and ultimately to plan conservation measures. For some species, such as small pelagic seabirds, foraging grounds are difficult to locate and remain largely unknown. We used miniaturised GPS devices (∼0.95g) to study foraging movements of Mediterranean Storm-petrels Hydrobates pelagicus melitensis during the incubation period. A total of 43 individuals at Benidorm colony (southwestern Mediterranean Sea) were tracked during a single foraging trip. We first assessed potential negative effects of the tracking devices. We recorded 22 complete foraging trips and measured home-range, foraging areas and the degree of overlap among individuals. We used first passage time analyses (FPT) to differentiate foraging/resting from flying/travelling activities and to infer potential foraging areas. All tracked birds returned to the colony. On average, individual body weight slightly decreased after foraging trips, suggesting a small immediate negative effect of the device. Tracked birds had high breeding success (0.71). Foraging trips lasted between 1 and 4.5 days with the total distance travelled ranging between 303.14 and 1,726.53km. The visited areas covered the whole south-western part of the Mediterranean Sea. Tracked individuals shared more than 50% of their home-range areas. Foraging areas were located further from the colony than previously thought (from 240 to 469km away) on deep sea areas of the Alboran Sea and Cartagena Canyons. Further studies are needed to locate foraging grounds during other life-cycle periods and to evaluate repeatability yearly, in order to determine the important marine areas for the species.—Rotger, A., Sola, A., Tavecchia, G. & Sanz-Aguilar, A. (2021). Foraging far from home: GPS-tracking of Mediterranean Storm-petrels Hydrobates pelagicus melitensis reveals long-distance foraging movements. Ardeola, 68: 3-16., Funds were provided by the project CNME19/0301/39 from the Generalitat Valenciana and the project CGL2017-85210-P from the Spanish Minister of Science, Innovation and Universities. ASA was supported by a “Ramon y Cajal” fellowship (RYC-2017-22796) and GT was supported by I. Hendriks.

The datasets contain measures of length and width of the egg of three species of Seabirds., Measures of egg volume of three seabirds: the Scopoli's shearwater Calonectis diomedea, the Sandwich tern Thalasseus sandvicensis and the Audouin’s gull Ichthyaetus audouinii in three colonies of the Western Mediterranean., No

The Strait of Gibraltar has some of the highest maritime activity in the world. Its populations of cetaceans are threatened by noise, chemical pollution, and collisions by the many boats crossing the strait. One of the greatest threats identified in cetaceans in the Mediterranean are epizootics that severely affect the most sensitive vital rate in long-lived species: adult survival. By a multi-event analysis of a 16-year database of long-finned pilot whale photo identification capture–recapture data, we analysed adult survival in the Strait of Gibraltar’s resident population and evaluated the possible effects of epizootics on this vital rate. We identified the large effect of a morbillivirus epizootic that occurred in 2006–2007, but we also revealed a second collapse in survival in 2011, probably due to another morbillivirus epizootic. These episodes seem to affect sexes differently, with females being less affected than males. Interestingly, the morbillivirus epizootic not only sharply decreased survival after the episode, but the effect extended over time, probably showing post-epizootic sequelae. These disease outbreaks have increased during the last decades worldwide and could be linked to anthropogenic threats such as organochlorine contamination. This may explain the high frequency of epizootics in the Gibraltar area. We warn about the conservation status of this long-finned pilot whale population and recommend the application of measures to reduce contamination on this nutrient-rich area to improve conditions for many marine species inhabiting this area., We thank Lionel Minvielle Sebastia for his help on the genetic analysis that were supported by grants from the CNRS, the Ministère de la Recherche Scientifique and La Fondation pour la Recherche Médicale/Fondation BNP-Paribas. Data have been presented previously as a poster at the World Marine Mammal Conference in 2019. https://www.wmmconference.org/wp-content/uploads/2020/02/WMMC-Book-of-Abstracts-3.pdf. Funding were partially provided by the AEI, MCIN and FEDER funds (CGL2017-85210), Fundacion Loro Parque, Fundación Biodiversidad, and by Agence Erasmus+ France.
Funding: Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This study was funded by the Spanish Ministry of Science (CGL2017-85210) and by Agence Erasmus + France., Peer reviewed

[EN] Egg size data for breeding Audouin's Gulls in the Ebro Delta during 1992-2021, with details on the age of the adults and clutch size., [ES] Datos de tamaño de huevo para la gaviota de Audouin nidificante en el Delta del Ebro durante 1992-2021, con detalles sobre la edad de los reproductores y tamaño de puesta., CIRIT (Generalitat de Catalunya, ACOM92/3051//10), ICONA, EU (LIFE projects (LIFE96/NAT/E/3118-B4-3200/96/502, LIFE NAT 2002/0502), Ministerio de Ciencia y Tecnología BOS2000-0569-C02-02, BOS2003-01960, CGL2006-04325/BOS, CGL2013-42203-R, CGL2017-85210-P), EU (Programme Quality of Life and Management of Living Resources, QLRT-2000-00839)., Peer reviewed

20 pages, 6 figures, 4 tables, 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), en-vironmental stochasticity over time, and space-use variability across species ranges must be considered, and their effects identified and corrected, to produce accurate estimates of spatial distribution using tracking data.
Innovation: We developed R functions to detect the effect of these sources of vari-ability in the distribution of animal groups when inferred from individual tracking data. These procedures can be adapted for their use in most tracking datasets and tracking techniques. We demonstrated our procedures with simulated datasets and showed their applicability on a real-world dataset containing 1346 year- round migratory trips from 805 individuals of three closely related seabird species breeding in 34 colonies in the Mediterranean Sea and the Atlantic Ocean, spanning 10 years. We detected an effect of ISF in one of the colonies, but no effect of the environmental stochasticity on the distribution of birds for any of the species. We also identified among-colony variability in nonbreeding space use for one species, with significant effects of popu-lation size and longitude.
Main conclusions: This work provides a useful, much- needed tool for researchers using animal tracking data to model species distributions or establish conservation measures. This methodology may be applied in studies using individual tracking data to accurately infer the distribution of a population or species and support the deline-ation of important areas for conservation based on tracking data. This step, designed to precede any analysis, has become increasingly relevant with the proliferation of studies using large tracking datasets that has accompanied the globalization process in science driving collaborations and tracking data sharing initiatives, We thank the following institutions for funding: EU H2020 pro-gramme through grant 634495; Seventh Framework Programme (Research Executive Agency) through Marie Curie Career Integration Grant 618841 (FP7-PEOPLE-2013- CIG); ESFRI LifeWatch Project; LIFE programme of the European Commission through projects LIFE10 NAT/MT090 and LIFE11 NAT/IT/000093; Ministerio de Ciencia e Innovación/Ministerio de Economia y Competitividad (Spain) through projects CGL2009- 11278/BOS, CGL2013-42585-P, C G L 2 0 1 3 - 4 2 2 0 3 - R , C G L 2 0 16 - 7 8 5 3 0 - R a n d C G L 2 0 17- 8 52 10 - P ; Organismo Autónomo de Parques Nacionales (Spain) through pro-ject 1248/2014; Fundação para a Ciência e a Tecnologia (MCTES, Portugal) through projects MARE-UID/MAR/04292/2019; IF/00502/2013/CP1186/CT0003, PTDC/BIA-ANM/3743/2014, PTDC/MAR-PRO/0929/2014, UID/AMB/50017/2019 and UIDP/50017/2020 + UIDB/50017/2020 (to CESAM); Office Français de la Biodiversité (France), through the Programme PACOMM, Natura2000 en mer; Hellenic Bird Ringing Centre; MSDEC (Malta). VMP was supported by pre-doctoral contract BES-2014- 068025 of the Spanish Ministerio de Industria, Economía y Competitividad; MM by grant SFRH/BPD/47047/2008 from the Portuguese Foundation for Science and Technology; JMRG by Ph.D. grant AP2009-2163 from the Spanish Ministerio de Educación; GDO and MMü by Ornis italica and by the Regione Siciliana and Assessorato Risorse Agricole e Alimentari thoriugh a grant to the Ringing Unit of Palermo; VHP by grant SFRH/BPD/85024/2012 from the Portuguese Foundation for Science and Technology; VN by grant SFRH/BPD/88914/2012 from the Portuguese Foundation for Science and Technology; and JN by the Spanish National Programme Ramón y Cajal (RYC-2015- 17809); GK and SX were partially funded by the Operational Program “Environment and Sustainable Development” (EPPERAA) of the National Strategic Reference Framework (NSRF) 2007-2013, co- financed by the ERDF and Greek EDP; FdF by a Ph.D. grant from the Coordination for the Improvement of Higher Education Personnel (CAPES—Brazilian government agency; Bex Process 1307/13-4); ZZ by a PhD grant from the University of Barcelona (APIF/2012); MCF by a PhD grant from the University of Barcelona; and RR by post-doctoral contracts of the PLEAMAR programme from MINECO and Fundación Biodiversidad (2017/2349), and Ministerio de Ciencia, in-novación y Universidades (RYC-2017- 22055). This publication is part of the project I+D+i/PID2020-117155GB-I00, funded by MCIN/ AEI/10.13039/501100011033, With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), Peer reviewed

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Prospecting in active breeders occurred in 85.7% of studied species, across 61.3% of sampled populations. Prospecting was more common in populations with frequent inter-annual changes of breeding sites and among females. These results contradict theoretical models which predict that prospecting is expected to evolve in relatively predictable and stable environments. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and understand the consequences of prospecting on fitness at the individual and population level., The study on black-legged kittiwakes in Norway was funded by the French Polar Institute (IPEV, programme no. 333 PARASITOARCTIQUE and OSU-OREME) and in France by Eoliennes Offshores du Calvados, Eoliennes Offshores des Hautes Falaises and the French Agency for Marine Protected Areas. Tracking of black-legged and red-legged kittiwakes in Alaska was supported by the North Pacific Research Board. The studies on Mediterranean gulls and gull-billed terns in Italy were funded by agreements between ISPRA and the Italian Ministry for the Ecological Transition (MiTE), formerly Ministry for Environment, Land and Sea Protection (MATTM); Decreti Min. Prot. 0004799-04/03/2016 and Prot. 34751-30/12/2019. The study of Audouin's gull in Spain was funded by the Spanish Ministry of Science, AEI/FEDER and UE (grants re. CGL2016-80963-R and CGL2017-85210-P), Project LIFE + INDEMARES (2009–2014; LIFE07NAT/E/000732), and was conducted by SEO/BirdLife. The study of Audouin's gull in Corse was founded by French Ministry of the Environment and CEN de Corse and in Italy by the Arcipelago Toscano National Park (‘The BIG FIVE’ project), under the LIFE project ‘Resto con Life’ (LIFE13 NAT/IT/0000471) and by ISPRA. Tagging of Audouin's and yellow-legged gulls in Croatia was funded under LIFE Artina project (LIFE17 NAT/HR/000594). Tracking of western gulls in Oregon was funded by the Bureau of Ocean Energy Management M14AC00026 and in California by several sources including SJSU RSCA and CSU COAST. Funds to monitor yellow-legged gull movements in the Balearic Islands were provided by Agencia Estatal de Investigación (AEI) and the EU found for regional development (FEDER), project n. CGL2017-85210-P. The survey of the yellow-legged gull in the province of Gipuzkoa (Basque Country, Spain) was funded by the Gipuzkoa Deputation. Tracking of gulls in Germany was funded mainly by the projects WINDBIRD (Grant no. 0325281, German Federal Ministry for Economic Affairs and Energy according to a decision of the German Bundestag), STopP (grant no. 03F672B, German Federal Ministry of Research and Education), and BIRDMOVE and TRACKBIRD (Grant nos. 3515822100 and 3519861400), Federal Agency for Nature Conservation, with funds from the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The study on lesser black-backed gulls in Bristol, United Kingdom, was funded by European Research Council under the European Union's Horizon 2020 research and innovation programme (Grant number 679355), the University Research Committee (URC)/Institute for Advanced Studies (IAS) Interdisciplinary Research Internship Scheme (IRIS) 2018, and the EPSRC Centre for Doctoral Training in Future Autonomous and Robotic Systems (FARSCOPE) at the Bristol Robotics Laboratory. Tagging of common terns in Croatia and Slovenia was founded by the Cooperation Programme Interreg V-A Slovenia – Croatia (Grant SLO-HR347). Tracking sandwich terns in the Netherlands was part of PMR-NCV, a program to study the effects of the extension of Rotterdam Harbour, and WOZEP, a program to study the effects of offshore wind farm developments in the Dutch coastal zone. Both programs were commissioned by Rijkswaterstaat WVL. The study of Aleutian terns in Alaska was funded by the National Fish and Wildlife Foundation Pacific Seabird Program (Grant ID 61777), the U.S., Peer reviewed

[Aim] To analyse the role of non-frugivorous birds on seed dispersal, seed dispersal by gulls is expected to be especially instrumental in island ecosystems, as these have a smaller subset of frugivores when compared to the mainland, and because long-distance dispersal is required for plant colonisation. Here, we investigated the seed dispersal of olives by gulls among 10 islands of the same archipelago to reveal if gulls contribute to long-distance seed dispersal including different islands, and how gulls' adaptation to domestic olives and individual differences in foraging activities affect their seed dispersal pattern., [Location] Balearic Islands in the Western Mediterranean Sea, Spain., [Taxon] Yellow-legged gulls (Larus michahellis), Domestic and wild Olives (Olea europaea and O. europaea var. sylvestris)., [Methods] We developed seed dispersal models of the two ecotypes of olives dispersed by gulls across an archipelago, based on GPS tracking data, gut passage time and seed viability., [Results] Mean dispersal distances were 7.67 (±12.48) km in wild and 12.57 (±13.08) km in domestic olives. 7.1% of wild and 8.5% of domestic olives were dispersed among islands. Among these, 8.2% of domestic seeds were transported from large to small islands where gull colonies are located, whereas wild olives were dispersed in more variable directions. Such dispersal pattern of two olive ecotypes was consistent despite the differences in dispersal distances among individuals., [Main Conclusions] Gulls contributed to long-distance olive seed dispersal including different islands. The seed dispersal of domestic olives to longer distances with specific directions may facilitate colonisation and expansion of that variant if the conditions of seed deposition sites are suitable. Our findings indicate that gulls are relevant vectors for long-distance dispersal of large fleshy fruits in island ecosystems where specialist large frugivores are absent., Gull monitoring was partially funded by the CGL2017-85210-P project from the Spanish Government (EUFEDER funds). We thank ‘Parque Natural de Sa Dragonera’ for their help with logistics and granting the permission to monitor and capture gulls, the Cabrera National Park for their support and permission to collect gull pellets and fruits (CGL2017-88122-P) and ‘Centro de Estudio y Protección del Medio Natural La Granja’ (Valencia) for allowing us to perform seed retention experiments. We thank CEIP Son Oliva and the Institute La Salle for their support in capturing gulls in Palma city. Many thanks go to the Conselleria de Medi Ambient of the Balearic Government for their permission to capture and mark gulls at different sites., Peer reviewed

Seasonal migration has evolved as an adaptation for exploiting peaks of resource abundance and avoiding unfavourable climatic conditions. Differential migratory strategies and choices of wintering areas by long-distance migratory species may impose varying selective pressures and mortality risks with fitness consequences. Recently developed tracking technologies allow wintering movements of migratory species to be studied. However, these technologies typically involve a limited number of tracked individuals, which gives low statistical power for any robust estimate of survival probabilities. Additionally, when utilising geolocators, data become accessible only upon individual recapture, presenting a potential source of bias. We used multievent modelling to include information of 147 identified wintering tracks in the analysis of 1104 long-term individual capture histories (2000-2022) of migratory seabird Calonectris diomedea and then test if individual preferences for wintering areas may drive heterogeneity in adult survival. We also examined individual fidelity to wintering areas and tested if climatic and oceanographic conditions, as represented by the wNAO and SOI climatic indices, influenced survival and fidelity. The probability of fidelity to a wintering area was ca. 0.79. Annual changes between areas were influenced by environmental variability driven by the wNAO. Survival probability was influenced by the SOI and differed between wintering areas; these differences coupled with high wintering site fidelity, generated individual heterogeneity in adult survival. Our study reveals that, over the last two decades, some individuals wintered in less suitable areas, with nonnegligible consequences on adult survival, the parameter to which the population growth rate is most sensitive in long-lived species. Winter oceanographic conditions such as stormy weather or the proximity to upwellings probably play a relevant role in driving survival heterogeneity. Further research is needed to enhance our understanding of how the interlinked effects of climate, local selective pressures and individual condition shape population dynamics in migratory species., The collection of the long-term demographic data was partially supported by several grants from the Spanish Ministerio de Ciencia e innovación/AEI and EU-FEDER funds (PID2021-124731NB-I00, PID2020-117155GB-I00/AEI/ 10.13039/501100011033, CGL2017-85210-P, CGL2016-78530-R, PIE202230I133) and through the ‘Maria de Maeztu Centre of Excellence’ accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198). RR was funded by postdoctoral contract RYC-2017-22,055 from the Ministerio de Ciencia, Innovación y Universidades, JGS was funded by an ICREA Academia award, and ASA received grant RYC-2017-22,796 funded by MCIN/AEI/ 10.13039/501100011033 and by ESF Investing in your future., With funding from the Spanish government through the "Maria de Maeztu Centre of Excellence" accreditation (CEX2021-001198)., Peer reviewed

15 pages, 5 figures, 2 tables, supporting information https://doi.org/10.1111/ddi.70013.-- Peer Review: The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1111/ddi.70013.-- Data Availability Statement: The novel code developed for this manuscript and the tracking data necessary to perform the analyses can be downloaded via Dryad at https://datadryad.org/stash/share/4hv2ejVbZcgyRvgBUj9Ah_34pIg2m_D0lxjRXxLZnao. The data on colony locations and breeding populations is available in Appendix S1 of Morera-Pujol et al. (2023). Methods to detect spatial biases in tracking studies caused by differential representativeness of individuals, populations and time. Diversity and Distributions, 29, 19–38. https://doi.org/10.1111/ddi.13642, Aim: In highly mobile species, Migratory Connectivity (MC) has relevant consequences in population dynamics, genetic mixing, conservation and management. Additionally, in colonially breeding species, the maintenance of the breeding geographical structure during the non-breeding period, that is, a strong MC, can promote isolation and population divergence, which ultimately can affect the process of lineage sorting. In geographically structured populations, studying the MC and differences in environmental preferences among colonies, populations, or taxa can improve our understanding of the ecological divergence among them.
Location: Atlantic Ocean and Mediterranean Sea.
Methods: We investigated the MC and non-breeding ecological niche of three seabird taxa from the genus Calonectris (n = 805 individuals). Using 1346 year-round trips from 34 different breeding colonies, we assess the level (from taxa to colony) at which MC and non-breeding spatial and environmental segregation emerge.
Results: At a taxon level, we found a clear difference in the non-breeding distributions between Cory's (C. borealis) and Scopoli's (C. diomedea) shearwaters, and a clear ecological divergence between Cory's and Cape Verde (C. edwardsii) shearwaters. At an intermediate aggregation level, we found that birds breeding in proximity had similar non-breeding habitat preferences, while birds breeding in very distant colonies (and therefore classified in different populations) had different non-breeding habitat preferences. Furthermore, within each taxon, we found more structure (i.e. stronger MC) and non-breeding divergence at an intermediate aggregation level than at the colony scale, where MC was weak.
Main Conclusions: These results suggest that conspecifics from nearby colonies mix in common non-breeding areas, but not with birds from more distant colonies or different taxa. These results support the need for management and conservation strategies that take into account this structure when dealing with migratory species with high connectivity, EU H2020 programme through grant 634,495; Seventh Framework Programme (Research Executive Agency) through Marie Curie Career Integration Grant 618,841 (FP7-PEOPLE-2013-CIG); ESFRI LifeWatch Project; LIFE programme of the European Commission through projects LIFE10 NAT/MT090 and LIFE11 NAT/IT/000093; Ministerio de Ciencia e Innovación/Ministerio de Economia y Competitividad (Spain) through projects CGL2009–11278/BOS, CGL2013-42585-P, CGL2013-42203-R, CGL2016-78530-R and CGL2017-85210-P; Organismo Autónomo de Parques Nacionales (Spain) through project 1248/2014; Fundação para a Ciência e a Tecnologia (MCTES, Portugal) through projects MARE-UID/MAR/04292/2019; IF/00502/2013/CP1186/CT0003, PTDC/BIA-ANM/3743/2014, PTDC/MAR-PRO/0929/2014, UID/AMB/50017/2019 and UIDP/50017/2020 + UIDB/50017/2020 (to CESAM); Office Français de la Biodiversité (France), through the Programme PACOMM, Natura2000 en mer; Hellenic Bird Ringing Centre; MSDEC (Malta). VMP was supported by pre-doctoral contract BES-2014-068025 of the Spanish Ministerio de Industria, Economía y Competitividad; MM by grant SFRH/BPD/47047/2008 from the Portuguese Foundation for Science and Technology; JMRG by Ph.D. grant AP2009-2163 from the Spanish Ministerio de Educación; GDO and MMü by Ornis italica and by the Regione Siciliana and Assessorato Risorse Agricole e Alimentari through a grant to the Ringing Unit of Palermo; VHP by grant SFRH/BPD/85024/2012 from the Portuguese Foundation for Science and Technology; VN by grant SFRH/BPD/88914/2012 from the Portuguese Foundation for Science and Technology; and JN by the Spanish National Programme Ramón y Cajal (RYC-2015-17,809); GK and SX were partially funded by the Operational Program “Environment and Sustainable Development” (EPPERAA) of the National Strategic Reference Framework (NSRF) 2007–2013, co-financed by the ERDF and Greek EDP; FdF by a Ph.D. grant from the Coordination for the Improvement of Higher Education Personnel (CAPES—Brazilian government agency; Bex Process 1307/13–4); ZZ by a PhD grant from the University of Barcelona (APIF/2012); MCF by a PhD grant from the University of Barcelona; and RR by postdoctoral contracts of the PLEAMAR programme from MINECO and Fundación Biodiversidad (2017/2349), and Ministerio de Ciencia, innovación y Universidades (RYC-2017-22,055). This publication is part of the project I + D + i/PID2020-117155GB-I00, funded by MCIN/AEI/, With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), Peer reviewed

Seabirds' distribution is generally influenced by the ecological dynamics of marine environments. Understanding how oceanographic features shape seabird foraging behaviour remains a challenge. We combined GPS tracking locations (n = 2883) of 39 European Storm-petrels (Hydrobates pelagicus) breeding in four West Mediterranean colonies during incubation over multiple years (2019–2021) with near-real-time remotely sensed oceanographic drivers. We model habitat selection using GPS tracking data from one colony, Benidorm Island, and use data from other three colonies for validation. We show that suitable foraging areas are strongly characterized by low sea surface temperature, high chlorophyll concentration and eddy kinetic energy. Based on this model, we predict habitat suitability maps for 2018–2022. Cross-validation using data from the other three colonies highlights that the identified suitable areas are universally applicable across other Storm-petrel colonies in the Western Mediterranean. We identified the Alboran Sea, the North African coast, the Gulf of Lion and the Ebro River Delta as the most suitable regions. These areas are characterized by high mesoscale variability, suggesting the importance of dynamic oceanographic features in determining foraging habitat. Identified main foraging areas are largely outside of Marine Protected Areas (MPAs), thus vulnerable to anthropogenic threats such as overfishing and energy infrastructure development. The critical foraging areas identified for this species underscore the need to expand the MPA network and/or adopt sustainable resource extraction in unprotected marine areas., Also thank Autoritat Portuaria de Balears, the Conselleria de Medi Ambient i Territori del Govern de les Illes Balears, Sant Lluis Town Council. Additional funds were provided by the Government of Balearic Islands, Generalitat Valenciana (CnME19/0301/39), and the Spanish Minister of Science, Innovation and Universities (CGL2017–85210-P). AR was supported by a “Vicenç Mut” fellowship (PD/004/2022). ASA was supported by a “Ramon y Cajal” fellowship (RyC-2017-22,796). This research was funded by Biodiversa+, the European Biodiversity Partnership under the 2022–2023 BiodivMon joint call for research proposals, co-funded by the European Commission (GA N°101,052,342) and Fundación Biodiversidad as funding organisations (project SEAGHOSTS).
This work was conducted within the framework of the activities of the Spanish Government through the “Maria de Maeztu Centre of Excellence” accreditation to IMEDEA (CSIC-UIB) (CEX2021–001198)., With funding from the Spanish government through the "Maria de Maeztu Centre of Excellence" accreditation (CEX2021–001198)., Peer reviewed

Sudden changes in populations are ubiquitous in ecological systems, especially under perturbations. The agents of global change may increase the frequency and severity of anthropogenic perturbations, but complex populations' responses hamper our understanding of their dynamics and resilience. Furthermore, the long-term environmental and demographic data required to study those sudden changes are rare. Fitting dynamical models with an artificial intelligence algorithm to population fluctuations over 40 y in a social bird reveals that feedback in dispersal after a cumulative perturbation drives a population collapse. The collapse is well described by a nonlinear function mimicking social copying, whereby dispersal made by a few individuals induces others to leave the patch in a behavioral cascade for decision-making to disperse. Once a threshold for deterioration of the quality of the patch is crossed, there is a tipping point for a social response of runaway dispersal corresponding to social copying feedback. Finally, dispersal decreases at low population densities, which is likely due to the unwillingness of the more philopatric individuals to disperse. In providing the evidence of copying for the emergence of feedback in dispersal in a social organism, our results suggest a broader impact of self-organized collective dispersal in complex population dynamics. This has implications for the theoretical study of population and metapopulation nonlinear dynamics, including population extinction, and managing of endangered and harvested populations of social animals subjected to behavioral feedback loops.

[eng] Identifying important foraging areas is fundamental for understanding the demographic drivers shaping species dynamics and for planning effective conservation measures. However, for small pelagic seabirds such as the Mediterranean Storm-petrel (<em>Hydrobates pelagicus melitensis</em>), foraging grounds are difficult to locate and remain largely unknown. We used miniaturised GPS devices (~0.95 g) to study foraging movements during the incubation period, tracking 43 individuals from the Benidorm colony (south-western Mediterranean Sea) over a single foraging trip. Potential negative effects of the devices were first assessed, and 22 complete foraging trips were obtained, allowing the estimation of home ranges, foraging areas and the degree of spatial overlap among individuals. First passage time (FPT) analyses were used to distinguish foraging or resting behaviour from travelling flights and to infer potential foraging areas. All tracked birds returned to the colony, and although body mass slightly decreased after foraging trips—suggesting a small immediate negative effect of the device—breeding success of tracked individuals was high (0.71). Foraging trips lasted between 1 and 4.5 days, with total distances travelled ranging from 303.14 to 1,726.53 km, covering most of the south-western Mediterranean Sea. Individuals shared more than 50% of their home-range areas, and foraging grounds were located much farther from the colony than previously thought (240–469 km), mainly over deep-sea areas of the Alboran Sea and the Cartagena Canyons. Further studies are required to identify foraging areas during other life-cycle stages and to assess interannual repeatability, in order to robustly determine the most important marine areas for the conservation of this species.