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- Year-round variation in the isotopic niche of Scopoli's shearwater (Calonectris diomedea) breeding in contrasting sea regions of the Mediterranean SeaPublication . Campioni, Letizia; Dell'Omo, Giacomo; Vizzini, Salvatrice; De Pascalis, Federico; Badalamenti, Fabio; Massa, Bruno; RUBOLINI, DIEGO; Cecere, Jacopo G.Top marine predators are key components of marine food webs. Among them, long-distance migratory seabirds, which travel across different marine ecosystems over the year, may experience important year-round changes in terms of oceanographic conditions and availability of trophic resources. We tested whether this was the case in the Scopoli’s shearwater (Calonectris diomedea), a trans-equatorial migrant and top predator, by sampling birds breeding in three environmentally different regions of the Mediterranean Sea. The analysis of positional data and stable isotopes (δ13 C and δ15N) of target feathers revealed that birds from the three regions were spatially segregated during the breeding period while they shared non-breeding areas in the Atlantic Ocean. Isotopic baseline levels of N and C (meso-zooplankton) were significantly different among marine regions during breeding. Such variation was reflected at the higher trophic levels of pelagic and demersal fish muscles as well as in shearwater feathers grown in the Mediterranean. δ15N- and δ13C-adjusted values of shearwaters were significantly different among populations suggesting that birds from different breeding areas relied on prey species from different trophic levels. Conversely, the non-breeding spatial and isotopic niches overlapped greatly among the three populations. Shearwater trophic niches during breeding were narrower and segregated compared to the non-breeding period, revealing a high plasticity in trophic resource use. Overall, this study highlights seasonal and region-specific use of trophic resources by Scopoli’s shearwater, suggesting a broad trophic plasticity and possibly a high adaptability to environmental changes.
- Habitat preferences, foraging behaviour and bycatch risk among breeding sooty shearwaters Ardenna grisea in the Southwest AtlanticPublication . Bonnet-Lebrun, Anne-Sophie; Catry, Paulo; Clark, Tyler J.; Campioni, Letizia; Kuepfer, Amanda; Tierny, Megan; Kilbride, Elizabeth; Wakefield, Ewan D.Pelagic seabirds are important components of many marine ecosystems. The most abundant species are medium/small sized petrels (<1100 g), yet the sub-mesoscale (<10 km) distribution, habitat use and foraging behaviour of this group are not well understood. Sooty shearwaters Ardenna grisea are among the world’s most numerous pelagic seabirds. The majority inhabit the Pacific, where they have declined, partly due to bycatch and other anthropogenic impacts, but they are increasing in the Atlantic. To evaluate the sub-mesoscale habitat preferences (i.e. the disproportionality between habitat use and availability), diving behaviour and bycatch risk of Atlantic breeders, we tracked sooty shearwaters from the Falkland Islands during late incubation and early chick-rearing with GPS loggers (n = 20), geolocators (n = 10) and time-depth recorders (n = 10). These birds foraged exclusively in neritic and shelf-break waters, principally over the Burdwood Bank, ~350 km from their colony. Like New Zealand breeders, they dived mostly during daylight, especially at dawn and dusk, consistent with the exploitation of vertically migrating prey. However, Falkland birds made shorter foraging trips, shallower dives, and did not forage in oceanic waters. Their overlap with fisheries was low, and they foraged at shallower depths than those targeted by trawlers, the most frequent fishing vessels encountered, indicating that bycatch risk was low during late incubation/early chick-rearing. Although our results should be treated with caution, they indicate that Atlantic and Pacific sooty shearwaters may experience markedly differing pressures at sea. Comparative study between these populations, e.g. combining biologging and demography, is therefore warranted.
- An ontogenetic perspective on migratory strategy of a long-lived pelagic seabird: Timings and destinations change progressively during maturationPublication . Letizia, Campioni; Dias, Maria P.; Granadeiro, José Pedro; Catry, PauloThe processes that drive the ontogeny of migratory strategies in long-lived animals with slow maturation remain enigmatic. While some short-lived migrants are known or believed to repeat the same migratory patterns throughout their lives, little is known on the time required for immature long-lived migrants to progressively acquire adult-like migratory behaviours, or which aspects take longer to refine during the maturation process. Here, we studied the ontogeny of long-distance migratory strategies and related patterns of spatial distribution in a long-lived seabird species during the annual cycle. To do so, we deployed light-level geolocators on 4- to 9-year-old immature Cory's shearwaters (Calonectris borealis) and on breeding adults. We revealed that migratory timings and destinations of young shearwaters progressively changed with age. The effect of ageing was remarkably evident on spring migratory performance and phenology. Birds gradually shortened the duration of the non-breeding period by advancing departure date and reducing travelling time, which resulted in a sequential arrival at the colony of the various age contingents. Ageing immatures gradually changed from a more exploratory strategy to a more conservative way of exploiting resources, reducing both their year-round spatial spread across oceanic domains and the total distance travelled. Immatures always performed a trans-equatorial migration to the Southern Hemisphere, contrasting with 17% of the adults which remained in the North Atlantic year-round. Finally, during the breeding season immatures were widely dispersed through the North Atlantic reducing their overlap with breeding adults. Our long-term study provides empirical support to the hypothesis that in long-lived species, the refinement of migratory behaviour and year-round spatial distribution is a progressive process mediated by age and experience, where life stage constraints and competition for resources may also play a role. The emerging pattern suggests that for some avian taxa, the ontogeny of migratory strategy is a prolonged, complex and dynamic process.
- Mud-puddling on roadsides: a potential ecological trap for butterfliesPublication . Campioni, Letizia; Marengo, Ilaria; Román, Jacinto; D'Amico, MarcelloRoad-kill represents a major threat for butterflies and more generally for pollinators. Here we report an observation of conspicuous aggregations of butterflies mud-puddling on roadsides and, for this reason, being massively road-killed by farm vehicles.
- Exposure of an endangered seabird species to persistent organic pollutants: Assessing levels in blood and link with reproductive parametersPublication . Campioni, Letizia; Oró-Nolla, Bernat; Granadeiro, José P.; Silva, Monica C.; Madeiros, Jeremy; Gjerdrum, Carina; Lacorte, SilviaOcean contamination, particularly from persistent organic pollutants (POPs), remains a significant threat to marine predators that occupy high trophic positions. Long-lived procellariform seabirds are apex predators in marine ecosystems and tend to accumulate contaminants. Prolonged exposure to pollutants negatively affects their fitness including reproductive success. Low breeding success may represent a hurdle for the restoration of small and endangered seabird populations, including several highly threatened gadfly petrels. Here we investigated the annual variation (2019 and 2022) in organochlorine pesticide (OCP), polychlorinated biphenyl ether (PCB), polybrominated diphenyl ether (PBDE), and polycyclic aromatic hydrocarbon (PAH) exposure in the endangered Bermuda petrel (Pterodroma cahow), and the relationship between female contaminant burden and breeding parameters. We found that petrels were exposed to a wide range of pollutants (33 out of 55 showed
- Citizen science data reveal possible multi-decadal phenological changes in the arrival time of a migratory tropical seabird species at the breeding groundPublication . Letizia, Campioni; Madeiros, Jeremy; Becciu, Paolo· Changes in climate and weather variability are having global impacts on the lives of organisms, particularly on upper trophic-level predators such as pelagic seabirds. In the North Atlantic, migratory seabirds are expected to respond to climate variability by adjusting their seasonal events, including the timing of migration and arrival at the breeding site. The timing of these events may be infuenced by large-scale atmospheric phenomena such as the North Atlantic Oscillation (NAO) and the Atlantic Multi-decadal Oscillation (AMO) that gauge temporal and spatial variation in environmental conditions across the North Atlantic. In the Bermuda Islands (32° 17′ 58″ N, 64° 47′ 25″ W), the White-tailed tropicbird (Phaethon lepturus catsbyii) is one of the few breeding seabird species which returns every year between February and March after migration. According to local belief their return announces the arrival of Spring, and this cultural importance means that the event is noticed. Only recently, early tropicbird returns have been recorded and associated with unusual climate/weather conditions experienced across the region. This raised the question of whether the species is showing some change in its phenology and whether it might be afected by changing climatic conditions. To answer this question, we investigated tropicbird arrival dates at Bermuda using current and historic observation data retrieved from the eBird citizen science platform. After accounting for biases inherent to opportunistic data collection, we selected and used the frst annual observation as a proxy for bird arrival time at the Bermuda breeding ground from 1953 to 2023. We found that tropicbird observation dates advanced substantially over the past 70 years suggesting that arrival time has been likely shifting of ca. 20–25 days. However, frst observation dates were not related to the variation in annual or winter NAO and AMO Indices, and further investigation is required to understand the underlying causes of these progressively early arrivals. Overall, the study highlights that citizen-science data can be used to unveil hidden phonological patterns when a standardized long-term data collection is missing.
- Size-assortative mating in a long-lived monogamous seabirdPublication . Visalli, Francesca; De Pascalis, Federico; Morinay, Jennifer; Campioni, Letizia; Imperio, Simona; Catoni, Carlo; Maggini, Ivan; Benvenuti, Andrea; Gaibani, Giorgia; Pellegrino, Irene; Ilahiane, Luca; Chamberlain, Dan; RUBOLINI, DIEGO; Cecere, Jacopo G.Mate choice is a key process in animals to optimize the ftness benefts of reproduction, and it is generally guided by phenotypic features of potential partners that mirror reproductive abilities. Assortative mating occurs when there is within-pair selection for specifc functional traits that can confer ftness benefts. Assortative mating can be positive if mates are more similar, and negative if they are more dissimilar than expected by chance. Mate choice is particularly important in long-lived species with biparental care, such as procellariforms that form long term monogamous bonds. We assessed the mating strategy of a sexually dimorphic Mediterranean procellariform, the Scopoli’s Shearwater (Calonectris diomedea), by testing for assortative mating according to bill (in accordance with previous studies on a sister species) and tarsus size (proxy of body size). We found that shearwaters adopted a positive size-assortative mating by tarsus length, while mating for bill size was random. Moreover, tarsus length was positively correlated with the duration of incubation shifts, when individuals are fasting on eggs. The observed assortative mating could be the results of choice by similarity between individuals, likely because partners with similar relative size have similar tolerance to fasting. Alternatively, the observed pattern could be the product of mutual mate choice, with a selection for large size that could confer competitive abilities in nest selection, defense, foraging aggregations and fasting ability. While our data suggest strong assortative mating in the Scopoli’s Shearwater (R=0.4), we cannot fully disentangle the multiple processes at play acting on mate choice.
- Trace elements’ reference levels in blood of breeding black-browed albatrosses Thalassarche melanophris from the Falkland IslandsPublication . Furtado, Ricardo; Granadeiro, J. P.; Campioni, Letizia; Silva, Mónica; Pereira, Eduarda; Catry, PauloTrace elements' concentration in the ocean is fast growing and is a source of major concern. Being charismatic and at the top of food chains, seabirds are often used as biological monitors of contaminants. We studied the concentration of trace elements in blood of black-browed albatross from the Falklands Islands, which we here show, by tracking with geolocators, forage over most of the Patagonian Shelf. Levels of trace elements were measured in males and females from two different islands. Blood concentrations of trace elements were not significantly different between islands, which is consistent with observations from foraging behavior revealing that birds from both islands foraged in broadly the same areas in the months before sampling. Arsenic and selenium concentrations in females were higher than in males. Sex-related differences in the concentration of these elements may be related to unknown slight differences in diet or to differences in assimilation between sexes. These results provide reference values for monitoring elemental contamination in the Patagonian Shelf Large Marine Ecosystem using black-browed albatrosses, one of the most abundant top predators and a suitable sentinel for the region's environmental health.
- Coastal connectivity of marine predators over the Patagonian Shelf during the highly pathogenic avian influenza outbreakPublication . Riaz, Javed; Orben, Rachael; Gamble, Amandine; Catry, Paulo; Granadeiro, Carlos; Campioni, Letizia; Tierney, Megan; Baylis, AlastairAnimal movement and population connectivity are key areas of uncertainty in efforts to understand and predict the spread of infectious disease. The emergence of highly pathogenic avian influenza (HPAI) in South America poses a significant threat to globally significant populations of colonial breeding marine predators in the South Atlantic. Yet, there is a poor understanding of which species or migratory pathways may facilitate disease spread. Compiling one of the largest available animal tracking datasets in the South Atlantic, we examine connectivity and inter-population mixing for colonial breeding marine predators tagged at the Falkland Islands. We reveal extensive connectivity for three regionally dominant and gregarious species over the Patagonian Shelf. Black-browed albatrosses (BBA), South American fur seals (SAFS) and Magellanic penguins (MAG) used coastal waters along the Atlantic coast of South America (Argentina and Uruguay). These behaviours were recorded at or in close proximity to breeding colonies and haul-out areas with dense aggregations of marine predators. Transit times to and from the Falkland Islands to the continental coast ranged from 0.2–70 days, with 84% of animals making this transit within 4 days - a conservative estimate for HPAI infectious period. Our findings demonstrate BBA, SAFS and MAG connectivity between the Falkland Islands and mainland South America over an expansive spatial network and numerous pathways, which has implications for infectious disease persistence, transmission and spread. This information is vital in supporting HPAI disease surveillance, risk assessment and marine management efforts across the region.
- A framework for mapping the distribution of seabirds by integrating tracking, demography and phenologyPublication . Carneiro, Ana Paula B.; Pearmain, Elizabeth J.; Oppel, Steffen; Clay, Thomas A.; Phillips, Richard A.; Bonnet‐Lebrun, Anne‐Sophie; Wanless, Ross M.; Abraham, Edward; Richard, Yvan; Rice, Joel; Handley, Jonathan; Davies, Tammy E.; Dilley, Ben J.; Ryan, Peter G.; Small, Cleo; Arata, Javier; Arnould, John P. Y.; Bell, Elizabeth; Bugoni, Leandro; Letizia, Campioni; Catry, Paulo; Cleeland, Jaimie; Deppe, Lorna; Elliott, Graeme; Freeman, Amanda; Gonzalez-Solis, Jacob; Granadeiro, José Pedro; Grémillet, David; Landers, Todd J.; Makhado, Azwianewi; Nel, Deon; Nicholls, David G.; Rexer‐Huber, Kalinka; Robertson, Christopher J. R.; Sagar, Paul M.; Scofield, Paul; Stahl, Jean‐Claude; Stanworth, Andrew; Stevens, Kim L.; Trathan, Philip N.; Thompson, David R.; Torres, Leigh; Walker, Kath; Waugh, Susan M.; Weimerskirch, Henri; Dias, Maria P.1. The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life-history stages even though they can represent a substantial proportion of the total population. 2. Here we develop a methodological framework for estimating populationlevel density distributions of seabirds, integrating tracking data across the main life-history stages (adult breeders and non-breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life-history stage. 3. We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non-breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population-level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all lifehistory stages. 4. Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data-poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at-sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations.