Browsing by Author "Catry, Paulo"
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- Absence of haemosporidian parasite infections in the long-lived Cory’s shearwater: evidence from molecular analyses and review of the literaturePublication . Campioni, Letizia; Martínez-de la Puente, Josué; Figuerola, Jordi; Granadeiro, José P.; Silva, Mónica C.; Catry, PauloThe apparent scarcity or absence of blood parasites in some avian groups, such as seabirds, has been related to intrinsic and extrinsic factors including host immunological capacity, host-parasite assemblage, and ecological parameters, but also to reduced sensitivity of some methods to detect low parasite prevalence/intensities of infection. Here, we examined the haemosporidian parasite prevalence in a breeding population of Cory's shearwater Calonectris diomedea borealis, a long-distance migrant seabird, nesting in the Macaronesian region, in the Eastern Atlantic. Previous studies on Calonectris diomedea complex were based on small sample sizes providing weak evidence for a lack of infections by haemoparasites. Here, we investigated the presence of both parasite infections in C. d. borealis and larvae of potential mosquito vectors on the area. By employing a PCR-based assay, we extensively examined the prevalence of blood parasites belonging to the genera Plasmodium, Haemoproteus, and Leucocytozoon in 286 individuals from different life stages (i.e., chicks, immatures, sabbatical, and breeding adults), facing their specific energetic trade-offs (immunological functions vs. life history activities). We sampled immatures and adult shearwaters, of different sexes, ages, and migratory origins, from two sub-colonies. None of the sampled individuals were infected by these parasites, supporting the hypothesis that there was no in situ or ex situ transmission of vector-borne parasites in marine habitats irrespective of host's life stage and in spite of the presence of the potential Plasmodium vector Culiseta longiareolata breeding in the area. These results suggest that the lack of transmission of haemosporidian parasites on Selvagem Grande may be related to the lack of suitable dipteran vectors at the study sites, which may result from the geographic isolation of this area.
- Absence of haemosporidian parasite infections in the long-lived Cory’s shearwater: Evidence from molecular analyses and review of the literaturePublication . Campioni, Letizia; Martínez-de la Puente, Josué; Figuerola, Jordi; Granadeiro, José Pedro; Silva, Mónica C.; Catry, PauloThe apparent scarcity or absence of blood parasites in some avian groups, such as seabirds, has been related to intrinsic and extrinsic factors including host immunological capacity, host-parasite assemblage, and ecological parameters, but also to reduced sensitivity of some methods to detect low parasite prevalence/intensities of infection. Here, we examined the haemosporidian parasite prevalence in a breeding population of Cory's shearwater Calonectris diomedea borealis, a long-distance migrant seabird, nesting in the Macaronesian region, in the Eastern Atlantic. Previous studies on Calonectris diomedea complex were based on small sample sizes providing weak evidence for a lack of infections by haemoparasites. Here, we investigated the presence of both parasite infections in C. d. borealis and larvae of potential mosquito vectors on the area. By employing a PCR-based assay, we extensively examined the prevalence of blood parasites belonging to the genera Plasmodium, Haemoproteus, and Leucocytozoon in 286 individuals from different life stages (i.e., chicks, immatures, sabbatical, and breeding adults), facing their specific energetic trade-offs (immunological functions vs. life history activities). We sampled immatures and adult shearwaters, of different sexes, ages, and migratory origins, from two sub-colonies. None of the sampled individuals were infected by these parasites, supporting the hypothesis that there was no in situ or ex situ transmission of vector-borne parasites in marine habitats irrespective of host's life stage and in spite of the presence of the potential Plasmodium vector Culiseta longiareolata breeding in the area. These results suggest that the lack of transmission of haemosporidian parasites on Selvagem Grande may be related to the lack of suitable dipteran vectors at the study sites, which may result from the geographic isolation of this area.
- Age-related variation in foraging behaviour in the wandering albatross at south georgia : No evidence for senescencePublication . Froy, Hannah; Lewis, Sue; Catry, Paulo; Bishop, Charles M.; Forster, Isaac P.; Fukuda, Akira; Higuchi, Hiroyoshi; Phalan, Ben; Xavier, José C.; Nussey, Daniel H.; Phillips, Richard A.Age-related variation in demographic rates is now widely documented in wild vertebrate systems, and has significant consequences for population and evolutionary dynamics. However, the mechanisms underpinning such variation, particularly in later life, are less well understood. Foraging efficiency is a key determinant of fitness, with implications for individual life history trade-offs. A variety of faculties known to decline in old age, such as muscular function and visual acuity, are likely to influence foraging performance. We examine age-related variation in the foraging behaviour of a long-lived, wide-ranging oceanic seabird, the wandering albatross Diomedea exulans. Using miniaturised tracking technologies, we compared foraging trip characteristics of birds breeding at Bird Island, South Georgia. Based on movement and immersion data collected during the incubation phase of a single breeding season, and from extensive tracking data collected in previous years from different stages of the breeding cycle, we found limited evidence for age-related variation in commonly reported trip parameters, and failed to detect signs of senescent decline. Our results contrast with the limited number of past studies that have examined foraging behaviour in later life, since these have documented changes in performance consistent with senescence. This highlights the importance of studies across different wild animal populations to gain a broader perspective on the processes driving variation in ageing rates.
- Albatrosses bathe before departing on a foraging trip: implications for risk assessments and marine spatial planningPublication . Granadeiro, José Pedro; Campioni, Letizia; Catry, PauloTracking studies of seabirds have generally focused in identifying areas used for foraging, in the hope of highlighting regions of energy transfer which may be important for seabird and general ecosystem conservation and special management. However, some sea areas may serve functions other than providing nutritional resources, which may be equally relevant, particularly if used by large numbers of individuals. In this paper, based on a study of 4 breeding colonies in the Falkland Islands and on 314 individuals tracked, we show that virtually all (97.8%) black-browed albatrosses Thalassarche melanophris (BBA) bathe in the close vicinity of the colony, remaining in the area for nearly an hour, before departing on a foraging trip. This compares with only 20 to 40% of the individuals landing close to the colony at the end of a foraging trip. The observed utilization of marine areas by BBA in a radius of 1 to 5 km around the nesting colony is one order of magnitude higher than elsewhere, including foraging hotspots. Clearly, even long-range flying birds such as albatrosses can make an intensive use of the sea-surface in the immediate vicinity of the colonies, and therefore any threats to seabirds in these areas (disturbance, pollutants, collision with artificial structures and light attraction) can potentially have a major impact at the population level. As such, the close neighbourhood of seabird colonies are potentially highly sensitive areas, and this needs to be taken into account when carrying out risk assessments or during marine spatial planning exercises.
- Albatrosses following fishing vessels: How badly hooked are they on an easy meal?Publication . Granadeiro, José Pedro; Phillips, Richard A.; Brickle, Paul; Catry, PauloFisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km) showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit.
- Albatrosses prospect before choosing a home: Intrinsic and extrinsic sources of variability in visit ratesPublication . Campioni, Letizia; Granadeiro, José Pedro; Catry, PauloIn long-lived species with delayed maturity, prebreeders are expected to gather information by visiting and sampling the quality of potential nesting areas (prospecting), before they choose where to breed. In most seabirds, this process is important because, once recruited, individuals generally remain sitefaithful throughout their long reproductive life. As many seabirds are believed to display low levels of natal dispersal, it is possible that natal philopatry is an obligate strategy for most individuals, with prospecting being a negligible activity during the prebreeding stage. Using ringing information and GPS technology, we tracked breeding adults and prebreeder black-browed albatrosses, Thalassarche melanophris, from a colony of the Falkland Islands, during the breeding season. Breeding adults rarely engaged in prospecting, whereas prebreeders showed a high propensity to visit other colonies. Most prebreeders started prospecting ashore when 4e5 years old and most of the younger individuals prospected more than one breeding colony, with some prospecting up to five colonies in just 9 days. Prospecting activity did not differ between males and females and rapidly declined as prebreeders aged, by which time individuals had probably already selected their future nesting site. Nestling body mass at 60 days of age and hatching date did not influence prospecting behaviour later in life. Prospecting was mostly directed at colonies within 10 km from the natal place, but occurred regularly up to 55e65 km. While distance from the natal place was a strong predictor of the probability of a colony being prospected, colony size and growth rate were not. Our results provide new insights into the role of prospecting in the process of recruitment, showing that even for highly philopatric birds, recruitment to the natal colony (or to another nesting site) has the potential to be informed, not done blindly.
- Allochrony is shaped by foraging niche segregation rather than adaptation to the windscape in long-ranging seabirdsPublication . Ventura, Francesco; Granadeiro, José P.; Catry, Paulo; Gjerdrum, Carina; De Pascalis, Federico; Viveiros, Filipe; Silva, Isamberto; Menezes, Dilia; Paiva, Vítor H; Silva, MónicaBackground Ecological segregation allows populations to reduce competition and coexist in sympatry. Using as model organisms two closely related gadfly petrels endemic to the Madeira archipelago and breeding with a two month allochrony, we investigated how movement and foraging preferences shape ecological segregation in sympatric species. We tested the hypothesis that the breeding allochrony is underpinned by foraging niche segregation. Additionally, we investigated whether our data supported the hypothesis that allochrony is driven by species-specific adaptations to different windscapes. Methods We present contemporaneous tracking and stable isotopes datasets for Zino’s (Pterodroma madeira) and Desertas (Pterodroma deserta) petrels. We quantified the year-round distribution of the petrels, characterised their isotopic niches and quantified their habitat preferences using machine learning (boosted regression trees). Hidden- Markov-models were used to investigate the effect of wind on the central-place movement speed, and a simulation framework was developed to investigate whether each species breeds at times when the windscape is most favourable to sustain their trips. Results Despite substantial spatial overlap throughout the year, the petrels exhibited diverging isotopic niches and habitat preferences during breeding. Both species used a vast pelagic region in the North Atlantic, but targeted two different mesopelagic ecoregions and showed a preference for habitats mostly differing in sea surface temperature values. Based on our simulation framework, we found that both species would perform trips of similar speed during the other species’ breeding season. Conclusions The different breeding schedules between the species are underpinned by differences in foraging habitat preferences and adaptation to the local environment, rather than to the windscape. Nevertheless, the larger Desertas petrels exploited significantly windier conditions, potentially unsustainable for the smaller Zino’s petrels. Furthermore, due to larger mass and likely higher fasting endurance, Desertas petrels engaged in central-placeforaging movements that covered more ground and lasted longer than those of Zino’s petrels. Ultimately, patterns of ecological segregation in sympatric seabirds are shaped by a complex interplay between foraging and movement
- Allopreening in the Black‐browed Albatross (Thalassarche melanophris): an exploration of patterns and possible functionsPublication . Gillies, Natasha; Guilford, Tim; Catry, PauloThe functions of display between breeding pairs of animals have been given little attention outside of sexual selection. Yet evidence suggests that display between partners is in fact most commonly observed following mate choice, and is often just as elaborate. In many bird species, allopreening, when one member of a pair preens the other, is a major component of display both pre- and post-pair formation. Despite this, there has been little investigation into its functions. Explanations that have been put forward tend to focus on its role in feather hygiene, which has limited phylogenetic support, or its function in the maintenance of the pair bond, though how this might occur or indeed what this actually represents has not been adequately explained. Phylogenetic evidence reveals that allopreening is most commonly observed in those species exhibiting high levels of partner retention and biparental care, and it appears to be functional in maintaining cooperation in parental behaviour in at least one species. In our observational study, we explored the patterns and putative functions of allopreening during the nest-relief displays of breeding pairs of Black-browed Albatrosses Thalassarche melanophris during incubation and chick-provisioning. Allopreening was an important feature of displays, constituting 30% of display time. We found that the bird returning from its foraging trip usually initiated allopreening, and preened more than its partner prior to change-over of nesting duties. We further found a positive relationship between the amount of time the pair spent in display and the duration of the subsequent foraging trip, providing tentative support for a function in maintaining cooperative parental behaviour between the parents. Although we cannot be conclusive as to its exact functions, we add to a limited literature the first exploration of functions for this conspicuous behaviour in albatrosses.
- An holistic ecological analysis of the diet of Cory’s shearwaters using prey morphological characters and DNA barcodingPublication . Garcia Alonso, Hany Rafael de Drummond Ludovice Garcia; Granadeiro, José Pedro; Waap, Silke; Xavier, José C.; Symondson, William O. C.; Ramos, Jaime; Catry, PauloKnowledge of the dietary choices and trophic niches of organisms is the key to understanding their roles in ecosystems. In seabird diet studies, prey identification is a difficult challenge, often yielding results with technique-specific biases. Additionally, sampling efforts are often not extensive enough to reveal intrapopulational variation. Immature animals, which may constitute up to 50% of a population, may occupy a significantly different trophic niche to more experienced birds, but this remains largely unexplored. We investigated the diet of Cory’s shearwater (Calonectris diomedea) from Selvagem Grande, an island located off the northwest African coast, collecting a total of 698 regurgitate samples over three consecutive breeding seasons. The diet was assessed using two complementary approaches for prey identification: conventional morphological analysis (using fish vertebrae, otoliths and cephalopod beaks) and DNA barcoding of the 16S rRNA mitochondrial gene, in cases where a positive identification could not be retrieved. Species assignments employed BLAST and distance-based methods, as well as direct optimization of the tree length based on unaligned sequences in POY. This method resulted in robust tree estimates and species assignments, showing its potential for DNA barcoding of stomach contents using hypervariable markers such as the 16S. The molecular approach increased taxonomic resolution and revealed an additional 17 taxa. Diet differed significantly according to breeding status, sex, breeding phase (prelaying and chick rearing) and year. Such direct evidence of trophic segregation within the same population has rarely been shown in seabirds and highlights the importance of including such variables in ecosystem-based management approaches.
- 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.