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SummaryPelagic seabird populations have declined strongly worldwide. In the North Atlantic there was a huge reduction in seabird populations following the European colonization of the Azores, Madeira and Canary archipelagos but information on seabird status and distribution for the subtropical region of Cabo Verde is scarce, unavailable or dispersed in grey literature. We compiled and compared the historical and current distribution of all seabird species breeding in the Cabo Verde archipelago, updated their relative abundance, investigated their inland habitat preferences, and reviewed their threats. Currently, the breeding seabird community in Cabo Verde is composed of Bulwer’s Petrel Bulweria bulwerii, White-faced Storm-petrel Pelagodroma marina aedesorum, Cape Verde Shearwater Calonectris edwardsii, Cape Verde Storm-petrel Hydrobates jabejabe, Cape Verde Petrel Pterodroma feae, Boyd's Shearwater Puffinus lherminieri boydi, Brown Booby Sula leucogaster, and Red-billed Tropicbird Phaethon aethereus. One breeding species is currently extinct, the Magnificent Frigatebird Fregata magnificens. The relative abundance of Cape Verde Shearwater, Boyd’s Shearwater, Cape Verde Petrel, and Cape Verde Storm-petrel was determined from counts of their nocturnal calls in Santo Antão, São Vicente, Santa Luzia, Branco, Raso and São Nicolau. Cape Verde Petrel occurred only on mountainous islands (Santo Antão, São Nicolau, Santiago, and Fogo) from mid-to high elevations. Larger species such as the Cape Verde Shearwater and Boyd’s Shearwater exhibited a wider distribution in the archipelago, occurring close to the coastline but at lower densities on populated islands. Small procellariforms such as the Cape Verde Storm-petrel occurred at high densities only on rat-free islets and in steep areas of main islands where introduced cats and rats are unlikely to occur. The main threats to seabird populations in Cabo Verde range from predation by introduced predators, habitat alteration or destruction, and some residual human persecution.

French Guiana region is one of the most productive in the world and hosts a wide variety of marine vertebrates. In the same time, anthropogenic activities are a growing concern in French Guiana, both in coastal and offshore areas. However, few studies are published on marine mammals, seabirds and potential interactions. Twenty-three marine mammal species are known to occur in the Exclusive Economic Zone (EEZ) and important seabird breeding sites are located in the area. Most of the existing literature relates to breeding birds and coastal cetaceans, but the continental slope appears to be an essential habitat for marine mammals and seabirds. Between October 22 and November 23, 2017, an oceanographic survey was conducted on the Guiana slope to study the quality of sediments and water. Three marine fauna observers (MFOs) were onboard to record sightings of marine mammals and seabirds opportunistically. During 462 h of visual effort in good sighting conditions, 313 sightings (824 individuals) were recorded: 61 marine mammals (501 individuals) and 252 seabirds (323 individuals). Seven seabird families were observed: Laridae (42%), Fregatidae (26%), Procellariidae (12%), Stercorariidae (10%), Hydrobatidae (4%), Sulidae (2%) and Phaethontidae (1%). 3% concerned wader species. The most frequently observed seabird species was the magnificent frigatebird ( Fregata magnificens ), as well as the common tern ( Sterna hirundo ), Cory’s shearwater ( Calonectris diomedea ) and the pomarine jaeger ( Stercorarius pomarinus ). Many Delphinidae species were observed ( Stenella longirostris , Stenella attenuata , Stenella frontalis , Delphinus delphis , Tursiops truncatus ) in addition to sperm whales ( Physeter macrocephalus ) and humpback whales ( Megaptera novaeangliae ). Only a few sightings of humpback whales have been previously recorded in this area. Sighted individuals were mainly mother-calf pairs suggesting that the area may be an extended part of a calving ground for humpback whales.

Compensating for wind drift can improve goalward flight efficiency in animal taxa, especially among those that rely on thermal soaring to travel large distances. Little is known, however, about how animals acquire this ability. The great frigatebird ( Fregata minor ) exemplifies the challenges of wind drift compensation because it lives a highly pelagic lifestyle, travelling very long distances over the open ocean but without the ability to land on water. Using GPS tracks from fledgling frigatebirds, we followed young frigatebirds from the moment of fledging to investigate whether wind drift compensation was learnt and, if so, what sensory inputs underpinned it. We found that the effect of wind drift reduced significantly with both experience and access to visual landmark cues. Further, we found that the effect of experience on wind drift compensation was more pronounced when birds were out of sight of land. Our results suggest that improvement in wind drift compensation is not solely the product of either physical maturation or general improvements in flight control. Instead, we believe it is likely that they reflect how frigatebirds learn to process sensory information so as to reduce wind drift and maintain a constant course during goalward movement.

Climate change affects every crevice and corner of the ecological world. Already we see seasonal effects on important ecosystems such as the marine habitats of the Galápagos Archipelago. This paper looks at the year 2100 in the IPCC scenario A1B, looking specifically at Chelonia mydas agassizii and seeing whether it will be a “winner” or a “loser” under climate change. We discover that while neonate hatchlings may benefit from a compressed laying period that offers them protection by way of numbers, and speed from the increased ocean temperatures (SST), they lose out many other places. Frigatebird and reef fish predation will increase, hatchling size and fitness may decrease, and a surplus of female hatchlings will be produced, or none at all as nest temperatures rise above the thermal mortality limit. Chelonia mydas agassizii will need serious conservation help if we wish to keep it on this earth by the year 2100 even if we opt for the A1B strategy.

International audience; Since 2005, we have recorded annual episodes of alphaherpesvirus outbreaks in chicks of magnificent frigatebird Fregata magnificens on the Ile du Grand Connétable Nature Reserve in French Guiana. In 2009, we found sooty terns, Onychoprion fuscatus, that live sympatrically with frigatebirds, with visible clinical signs of a potential viral infection. To determine if the symptoms observed in sooty terns could be associated with an alphaherpesvirus previously identified in frigatebirds, we carried out molecular screening of samples collected from seven individuals. We identified and characterized a novel viral sequence from five birds. BLAST searches, pairwise nucleotide, and amino acid sequence comparisons, as well as phylogenetic analyses confirmed that the sequence belonged to the Herpesviridae family, of the Alphaherpesvirinae subfamily. We observed that it clustered with strains isolated from Podargidae (Caprimulgiformes), Columbiformes, and Falconiformes, but was distinct from the frigatebird herpesvirus. We have tentatively named it Onychoprion fuscatus alphaherpesvirus 1, (OfusAHV1). These two sequences, although found syntopic on the Ile du Grand Connétable, belong to two distinct alphaherpesvirus strains. Thus, the clinical symptoms showed by sooty terns do not likely result from a cross-species transmission event. Future work is needed to better characterize the virus and to investigate herpesvirus prevalence in healthy, free-ranging sooty terns, and to assess the impact of the virus on population viability.

Tracking of seabirds has been used to identify foraging hotspots, migratory routes and to assess at-sea threats facing populations. One such threat is the potential negative interaction between sea...

The work on Ascension Island was partly funded by a Darwin Grant (# 19026) to Ascension Island Government and the University of Exeter (A.B. and B.G.), managed on-island by N.W. and S.W. Nigel Butcher and Andrew Asque assisted with preparation of loggers and equipment, and Elizabeth Marsden kindly provided the base station to download data.

Species that inhabit spatially-distinct regions at different stages of their lifecycle pose challenges to conservation managers, particularly when distributions span international or jurisdictional boundaries. Despite the importance of non-breeding habitat to the persistence of individuals and species, there remains limited information on the habitat requirements of many species during the non-breeding period. We used Global Positioning System tracking devices to determine the non-breeding movements of Great Frigatebirds, Fregata minor, and Lesser Frigatebirds, F. ariel, across much of Southeast Asia. These data were analysed with MaxEnt modelling to identify important habitat features for non-breeding frigatebirds and inform priorities for targeted conservation measures. Models with the greatest predictive performance were influenced strongly by bathymetry. Predicted habitat suitability was greatest in shallow waters. Similarly, warmer waters had greater predicted suitability during the wet season. We also identify 45 roosting sites that form an important component of the habitat used by non-breeding frigatebirds in this region. The existing marine protected area (MPA) network contains only a small proportion of habitat identified as suitable or optimum for non-breeding frigatebirds. This is of particular concern given that some parts of the region’s marine environment are among the most heavily human-impacted in the world. Our findings can be used to implement spatially-targeted conservation measures such as education campaigns focusing on bycatch reduction and subsidies for bycatch reduction methods (e.g., streamer lines) for fisheries operating in suitable and optimum habitat. They could also inform placement of additional MPAs to maintain habitat integrity in areas we identified as suitable or optimum habitat, particularly when these habitats occur in close proximity to roosting sites. Such approaches will likely provide benefits to frigatebird populations tracked in the present study as well as those dispersing to the study region from other ocean basins.

In this paper, we describe the skulls of Magnificent Frigatebird Fregata magnificens (Fregatidae) and Brown Booby (Sulidae) Sula leucogaster, with focus on the structures associated with the Musculi mandibulae. We discuss the results in the context of the feeding biology of the two species, which feed mainly on flying fish and squids. Frigatebirds capture prey from just above, or just below, the water surface in flight. The hook-shaped Apex maxillae in F. magnificens can be viewed as an adaptation for grasping prey from near the water surface. Boobies catch prey by plunging; thus, the dorsoventrally flattened skull and conical bill of S. leucogaster may reduce water resistance when it dives, or swims underwater. The bill is long in both species, such that it is on average 70% of the whole skull length in F. magnificens and 60% in S. leucogaster. Consequently, the Mm. mandibulae in the two species are more posteriorly positioned relative to the Apex rostri. This results in low mechanical advantage for the mandible opening-closing lever, indicating adaptations for a fast, rather than a strong, bite. Fast-moving mandibles would be advantageous for ‘mandibulating’ prey while swallowing. The Fossa musculorum temporalium and the Palatum osseum in both species provide a broad area for origins of the Musculus adductor mandibulae externus (all parts) and the Musculus pterygoideus. The Processus orbitalis quadrati is longer and thicker in F. magnificens than in S. leucogaster, and so is the Musculus pseudotemporalis profundus. We suggest that Mm. adductores mandibulae are relatively well developed in the two species; therefore, their mandibulae are still probably capable of a powerful adduction. In both species there is a mechanisms that contribute to protect the jaws from disarticulation and damage. Such mechanism involves the incorporation of a ‘flange-like’ Crista intercotylare on the Margo medialis cotylae medialis fossae articularis quadratica that grips the Condylus medialis quadrati. In S. leucogaster, the retractor-stop ‘notch’ formed by Ossa lacrimale et nasale also serves to protect the jaws against sudden external forces when birds are diving or swimming underwater for prey. A more detailed hypothesis for the jaw movements and strength in F. magnificens and in S. leucogaster and their relation with feeding habits should necessarily incorporate data on the jaw and anterior neck musculatures.

Flight traits mediated by symmetry should be constrained by mechanical or aerodynamic effects. Natural asymmetry and external tail feather length could have unfavorable effects on aerodynamic performance and affect the survival of highly aerial birds. The Magnificent Frigatebird, Fregata magnificens , is a long-lived, highly aerial seabird with a deeply forked tail, and an extraordinary division of labor between sexes. Its flight pattern is soaring and dynamic, it also has fast active flight and acrobatic maneuvers. We explore the possible effect of tail streamer asymmetry and tail length on annual apparent survival of Magnificent Frigatebirds by using 6 years (2000-2005) of capture-mark-resighting of live-encounter data analysis. Male frigatebirds showed significant differences between left and right tail streamer length, and tail asymmetry differences between sexes. Models did not find a clear effect of tail streamer asymmetry and tail length, as individual covariates, on annual apparent survival by sex. Natural variation in a secondary sexual trait like those explored here likely does not affect apparent survival. Life-history strategies such as flight pattern, breeding behavior, and tail moult may constrain any negative effects. Longer mark-resighting studies and additional modelling could answer conclusively the association between survival and flight traits in Magnificent Frigatebirds.

International audience; Outbreaks of wildlife diseases are occurring at an unprecedented rate. In French Guiana, recurrent episodes of frigatebird chicks’ mortality due to a viral disease that first appeared in 2005 have recently turned into massive mortality episodes (85–95%) of chicks. One of the suggested hypotheses behind the appearance of the disease is food limitation due to the recent decline of local shrimp fishery boats on which frigatebirds rely for opportunistic feeding. We therefore experimentally fish‐supplemented frigatebird chicks with and without clinical signs of the disease. Food supplementation protected all chicks from the appearance of clinical signs of the disease and increased survival perspectives of sick chicks. These results suggest that food shortage might decrease resistance of chicks to infectious diseases and that using a specifically tailored food supplementation regime could be a complimentary tool to protect frigatebirds and other endangered birds from disease outbreaks threatening them with extinction.

International audience; 1. Diet quality may have an important effect on the regulation of oxidative statusand the immune system during an infectious disease. However, the relationshipamong intake of specific dietary molecules, an individual’s oxidative status and theoccurrence and progress of a viral disease remains almost unexplored in free‐livingorganisms.2. Here, we study a wild, long‐lived animal, the Magnificent frigatebird Fregata magnificensto investigate: (a) the differences in a number of physiological traits (biomarkersof blood oxidative status, corticosterone (CORT), immunity andinflammation) between sick and healthy nestlings; and (b) whether experimentallyincreased intake of resveratrol (a polyphenol with antioxidant and antiviral properties)affects these physiological markers during the progress of a severe viraldisease.3. Birds with visible clinical signs showed higher oxidative damage, haemolysis andhaemagglutination scores and lower antioxidant defences in comparison withbirds without clinical signs. At the end of the experiment, supplemented birdsshowed the following: (a) increased plasma haptoglobin levels and circulating antioxidantdefences; (b) reduced generation of lipid oxidative damage; and (c) negligibleto no influence on immune markers, baseline CORT levels and activity ofantioxidant enzymes.4. Our work illustrates how the availability of specific organic molecules in the dietmay constrain the individuals’ capacity to cope with viral infections in free‐livinganimals

In recent decades, several seabird populations have declined globally due to anthropogenic activities. In Brazil, 14 seabird species breed at four oceanic islands and one atoll: the Abrolhos, Fernando de Noronha, and Sao Pedro and Sao Paulo (SPSPA) archipelagos; the Trindade/Martin Vaz Islands; and the Atol das Rocas. Seven species are listed as nationally threatened by extinction. This study aimed to present new information on breeding seabird populations in Brazilian oceanic islands, compile all available data previously published and, when possible, to provide updated information on population estimates from censuses carried out sporadically at different islands between 2006 and 2013. Based on new data and the thorough review provided here, of the 35 seabird breeding populations analysed, 14% were increasing (as Red-billed Tropicbird Phaethon aethereus , Magnificent Frigatebird Fregata magnificens and Brown Noddy Anous stolidus in Abrolhos), 11% were decreasing (as Brown Booby Sula leucogaster in Atol das Rocas and Great Frigatebird Fregata minor in Trindade Island), 23% were stable (as White-tailed Tropicbird Phaethon lepturus in Fernando de Noronha and Brown Noddy and Black Noddy Anous minutus in Sao Pedro and Sao Paulo Archipelago), and the remaining 49% were unknown or not possible to evaluate. The Red-footed Booby ( Sula sula ) is locally extinct in Trindade Island, however there are colonies of only a few individuals of other species, such as the Audubon's Shearwater Puffinus lherminieri and Red- billed Tropicbird in Noronha, Black Noddy in Martin Vaz, and Great ( Fregata ariel trinitatis ) and Lesser ( F. m. nicoll i) Frigatebirds in Trindade, that may become extinct soon. Censuses at distinct periods of the breeding cycles and protocols were highly variable, making temporal comparisons difficult. These results indicate an urgent need for long-term studies to improve the scenario to assess seabird population trends based on comparable methodologies, in order to determine trends in the future.

We report a documented record of a Great Frigatebird Fregata minor at Fernando de Noronha, 360 km off the coast of northeast Brazil in the equatorial Atlantic. We presume that the bird at Fernando de Noronha originated from Trindade Island, c.1,800 km to the south, since it is the species' nearest breeding site, and we hypothesise that it moved with the south-east trade winds towards the north-east Brazilian coast.

Las diferentes anormalidades en el plumaje son resultado de múltiples factores ambientales y genéticos. En México se han reportado aberraciones en el plumaje de las aves, no obstante, todas se han clasificado como leucísticas (color blanco del plumaje debido a un gen recesivo). Otros tipos de aberraciones en el plumaje se han identificado, tales como el encanecimiento progresivo, el melanismo o las mutaciones, como la marrón, aún no reportadas para México. Durante trabajo de campo con aves en el estado de Nayarit, observamos individuos de seis especies de aves con plumajes anormales que caracterizamos como no leucísticos. Determinamos encanecimiento progresivo en pijije ala blanca (Dendrocygna autumnalis), zopilote aura (Cathartes aura), playero menor (Calidris minutilla) y golondrina tijereta (Hirundo rustica); plumaje marrón en avoceta americana (Recurvirostra americana) y plumaje ino en fragata magnífica (Fregata magnificens). El plumaje marrón y el ino involucran factores genéticos. El encanecimiento progresivo fue la aberración observada más frecuente, y diversos factores, que pueden ser genéticos, están involucrados en su expresión. Estas aberraciones, sin embargo, no habían sido previamente reportadas para aves en México.

This study used feathers of brown booby (Sula leucogaster) and magnificent frigatebird (Fregata magnificens) from Cagarras Archipelago, an area under strong anthropogenic influence, for evaluating the exposure of these seabirds to Cd, Sn, Mn, Cu and Se. Average concentrations (µg.Kg-1, dry weight) in feathers of brown booby were Cd 28.1, Sn 210.6, Cu 8233.4, Se 2343 and Mn 1635.7 and for frigatebird were Cd 82.9, Sn 319.6, Cu 8008.6, Se 3026 and Mn 5143. Regarding brown boobies, no significant difference was found between sexes or age (adults vs. juveniles) considering all measured elements. In addition, no significant correlation was observed between Sn, Cd and Cu concentrations and the following biometric parameters (BPs): body weight (BW) and tarsus (TrL), wing (WL), tail (TiL) and beak length (BL), for both species. However, significant negative correlations were observed between Se concentrations and TrL for magnificent frigatebird and brown booby. Concerning possible interspecific dissimilarities for juveniles, there was no significant difference for Sn, Se and Cd concentrations; however, significantly higher Cu and Mn concentrations were found in brown boobies. When adults were compared, significantly higher Cd and Mn concentrations were found in magnificent frigatebirds. These interspecific differences may occur due to dissimilarities in diet; however, the feeding habits of these seabirds around the study area are unknown. Additional studies on the diet of these species are necessary to shed further light on the interspecific differences verified. The concentrations found in the feathers of the seabirds in question do not denote a risk for the survival of the seabirds of the Cagarras Archipelago. DOI: http://dx.doi.org/10.17807/orbital.v10i2.1050

This study presents important morphometric and health parameters of 55 great frigatebirds from two locations on the Galápagos archipelago. All of the animals were robust, clinically healthy and behaving normally. This data adds to baseline health assessment values and provides reference blood parameter intervals., The great frigatebird, Fregata minor, is a widely distributed seabird native to the Galápagos archipelago. Haematology and blood chemistry parameters have been published for this species but not from the San Cristóbal and North Seymour great frigatebird breeding colonies. Analyses were run on blood samples drawn from 25 great frigatebirds captured by hand at their nests at Punta Pitt on San Cristóbal Island and 30 birds on North Seymour Island, Galápagos Islands. A portable blood analyser (iSTAT) was used to obtain near immediate field results for pH, pO2, pCO2, TCO2, HCO3−, haematocrit (Hct), haemoglobin (Hb), sodium (Na), potassium (K), chloride (Cl), ionized calcium (iCa), creatinine, urea nitrogen, anion gap and glucose. Blood lactate was measured using a portable Lactate Plus™ analyser. Average heart rate, respiratory rate, body weight, body temperature, biochemistry and haematology parameters were comparable to healthy individuals of other Fregatidae. The reported results provide baseline data that can be used for comparisons among populations and in detecting changes in health status among Galápagos great frigatebirds.

A humerus and a coracoid from the Early Eocene Wasatch Formation in the Washakie Basin of south-western Wyoming are the oldest materials (by ~2 million years) of the pelecaniform Limnofregata (Aves) and represent a new large species, Limnofregata hutchisoni sp. nov. This fossil is the oldest known member of the frigatebird lineage. Other than its large size relative to Limnofregata azygosternon and L. hasegawai, the new material is very similar morphologically to other known Limnofregata specimens. The size of this new species is comparable to the largest living species (e.g. Fregata minor and Fregata magnifiscens) and much larger than the two described species of Limnofregata. This fossil indicates that the hard minimum date previously advocated for molecular calibration of the split between Fregatidae and Suloidea is an underestimate by approximately two million years. The presence of early pelecaniform bird lineages (represented by Limnofregata and Masillastega) in limnic ecosystems prior to their known occurrences in marine deposits/habitats appears to indicate that some clades of pelecaniform birds may have undergone an evolutionary transition from freshwater to marine habitats in a pattern reminiscent of what has been suggested during the evolution of pinnipeds or that their palaeoecology included broader niches ranging across a variety of aquatic habitats. That transition in habitat occupation and the origin of many of the characteristic biological aspects present in the crown frigatebird clade likely occurred during a significant temporal gap (> 45 million years) in the fossil record of the frigatebird lineage after these earliest occurrences in the Early Eocene and before the oldest records of the extant Fregata species in the Pleistocene.

Migratory behavior varies extensively between bird taxa, from long distance migration to purely sedentary behavior. Variability in migratory behavior also occurs within taxa, where individuals within some species, or even populations, show mixed strategies. The same variability occurs in seabird species. We examined the migratory behavior of distinct populations of great frigatebirds Fregata minor in three distant oceanographic basins. Great frigatebird populations showed extensive variation in post-breeding migratory behavior. Birds from Europa Island (Mozambique Channel) made longdistance migration to numerous distinct roosting sites in the Indian Ocean, New Caledonia birds made shorter distance migrations to roosting sites in the southwestern Pacific Ocean, and Galapagos birds were resident within the archipelago year round. Juvenile birds from Europa Is. and New Caledonia dispersed widely whereas Galapagos juveniles were resident year round. The migratory behavior of Europa Is. and New Caledonia resulted in complete separation of foraging grounds between breeding adults, non-breeding adults, and juveniles, whereas in the Galapagos the overlap was complete. We suggest that population variability in migratory behavior may have arisen because of different environmental conditions at sea, and also depends on the availability of suitable roosting sites on oceanic islands. The results also highlight the capacity of frigatebirds to remain airborne most of the time even outside the breeding season when they have to molt.

The Magnificent Frigatebird (Fregata magnificens) is a monogamous, widespread, neotropical, pelagic seabird with low flight costs, high dispersal capacity, sex-biased dispersal, and female mate choice. Here, we adopt an integrative approach to evaluate the influence of behavior, male-biased philopatry, female choice, and geographic distance as non-physical barriers to dispersal acting on the genetic structure of magnificent frigatebirds in the 4 largest Mexican breeding colonies. We integrate ecological dispersal observations from tagging studies, analyses of maternally and biparentally inherited genetic markers, and group-structured population modeling. Mitochondrial DNA (matrilineal) and randomly amplified polymorphic DNA (biparental) data provided evidence of genetic differentiation between ocean basins, as well as among Eastern Pacific breeding colonies, and absence of a genetic pattern of isolation by distance. Our ecological, genetic, and modeling results are concordant with the expected effects of sex-biased philopatry and female mate choice as non-physical barriers to interbreeding, and suggest that geographic distance does not play a significant role in the genetic distinction of breeding colonies. The genetic differentiation found between Eastern Pacific and Caribbean, as well as that among Eastern Pacific breeding colonies is of consequence for the management plans and conservation measures of the Magnificent Frigatebird in the region.

Ecological segregation among coexisting seabird species can occur due to morpho- logical and behavioral differences. This segregation is especially important as it reduces competi- tion during the breeding season, when birds are central-place foragers. Furthermore, seasonal variation in oceanographic processes may change prey availability and shape seabird community trophic structure and species isotopic niche. We used stable isotope analyses of seabird whole blood and prey muscle in 5 tropical seabird communities representing 12 species (Charadri- iformes, Phaethontiformes, Procellariiformes and Suliformes) inhabiting 5 offshore islands off Brazil from 00°55' N to 20° 30' S and 65 to 1160 km from the coast. We evaluated how community trophic structure was correlated with morphology (body mass and bill length), and we verified seasonal variation in isotopic niche in 2 communities. Overall, seabird trophic position (TP) was positively correlated with body size, with frigatebirds and boobies occupying a higher TP than noddies and terns. Structuring of seabird communities according to body size probably occurred due to consumption of prey of different sizes and TP, which contributed to niche segregation by reducing interspecific competition during the breeding season. All species showed isotopic niche segregation at 2 islands, and ~60 to 70% of species segregated at the other islands, except at Atol das Rocas, where 43% of species segregated. Niche overlap occurred mainly among closely related species at Atol das Rocas, Fernando de Noronha and Trindade. The isotopic niche and TP changed across islands for all 3 boobies (red-footed Sula sula, brown S. leucogaster and masked S. dactylatra), brown noddy Anous stolidus and red-billed tropicbird Phaethon aethereus; these factors also changed seasonally in other species, such as in magnificent frigatebird Fregata mag- nificens, brown booby, both the red-billed P. aethereus and white-tailed P. lepturus tropicbirds and both the brown A. stolidus and black Anous minutus noddies. Such changes probably occurred due to differences in prey availability, opportunistic behavior (e.g. feeding on fishery dis- cards) and/or local foraging and diet specialization.

In the present study, trace elements and persistent organic pollutants (POPs) were quantified from Magnificent frigatebirds (Fregata magnificens) breeding at a southern Atlantic island. Stable isotope ratio of carbon (delta C-13) and nitrogen (delta N-15) were also measured to infer the role of foraging habitat on the contamination. For another group from the same colony, GPS tracks were recorded to identify potential foraging areas where the birds may get contaminated. Fourteen trace elements were targeted as well as a total of 40 individual POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The concentration of Hg in the blood was up to 6 times higher in adults (5.81 +/- 1.27 mu g g(-1) dw.) than in nestlings (0.99 +/- 0.23 mu g g(-1) dw.). A similar pattern was found for POPs. Sigma PCBs was the prevalent group both in adults (median 673, range 336 -2801 pg g(-1) ww.) and nestlings (median 41, range 19-232 pg g(-1) ww.), followed by the sum of dichlorodiphenyltrichloroethanes and metabolites (Sigma DDTs), showing a median value of 220 (range 75 -2342 pg g(-1) ww.) in adults and 25 (range 13-206 pg g(-1) ww.) in nestlings. The isotope data suggested that the accumulation of trace elements and POPs between adults and nestlings could be due to parental foraging in two different areas during incubation and chick rearing, respectively, or due to a shift in the feeding strategies along the breeding season. In conclusion, our work showed high Hg concentration in frigatebirds compared to non-contaminated seabird populations, while other trace elements showed lower values within the expected range in other seabird species. Finally, POP exposure was found generally lower than that previously measured in other seabird species. (C) 2016 Elsevier Ltd. All rights reserved.

We induced three adoptions during the period of biparental care by placing orphaned chicks of magnificent frigatebirds (Fregata magnificens) into nests of foster parents whose chick had died. Indirect parent-offspring recognition seemed to occur during the period of biparental care. A chick was adopted in one of our three trials; thus, adoption of orphaned chicks potentially could be used as a conservation strategy.

La asimetría de las rectrices exteriores en Fregata magnificens (rabihorcado) influye en su eficiencia de vuelo, mientras que la cola, profundamente bifurcada de esta especie sexualmente dimórfica, juega un papel crucial en su desempeño aerodinámico. Para evaluar la presión de la selección natural en la asimetría de la cola, modelamos el desempeño de rabihorcados machos y hembras simétricos y asimétricos adultos durante el vuelo de planeo en la colonia reproductiva de Isla Isabel, México, mediante la proporción levante:arrastre y las polares y superpolares de planeo. Encontramos diferencias significativas entre rabihorcados machos y hembras, simétricos y asimétricos cuando analizamos su desempeño en el vuelo de planeo y sus costos de compensación asociados. El modelo teórico indicó que la asimetría de la cola tendrá un efecto más grande en los machos que en las hembras durante el vuelo, y que los individuos asimétricos volarán menos eficientemente que los simétricos corrigiendo su asimetría en función de la velocidad al incorporar más costos de arrastre. Investigación futura para estimar las tasas de supervivencia de individuos simétricos y asimétricos, costos de construcción de nido y de éxito reproductivo podría revelar las ventajas de tener una cola simétrica en esta especie y elucidar si la asimetría tiene un costo en la adecuación.

Annual apparent survival rates from 323 marked immature Magnificent Frigatebirds (Fregata magnificens) were estimated using mark-recapture models for live encounter data in a six-year study (1998–2003) at Isla Isabel, the largest breeding colony in Western Mexico. A time and age immature apparent survival pattern was found: high and variable as yearling-juveniles (mean 1998–2000 = 9.78 ± 0.22) and, later, moderate and constant as juvenile-subadults and subadults (mean = 0.62 ± 0.11). Whereas resighting rate (p) increased with time (range = 0.00 [± 0.04] – 0.87 [± 0.11]). The results suggest variation in true survival and emigration during the juvenile life phase, high true survival and high site fidelity of juvenile-subadults and subadults during the interval after marking, and constant and either low true survival or high emigration in the subsequent intervals. Frigatebird apparent survival was predominantly higher in yearling juveniles than in subsequent age classes, an uncommon occurrence in ...

The Magnificent Frigatebird population breeding on Man-o-War Cay, Belize in 1980 laid their single eggs between mid-December and early April, and had a mean hatching date of mid- to late April. There were no differences between the sexes in the percent of time spent incubating eggs or brooding small chicks (males 48%, females 52%). However, males were not observed to feed larger (75–100 d) chicks. All 81 feedings of juvenile (approximately 1 year old) frigatebirds observed during 126 hr of observations were by females, and the majority of these feedings occurred at midday (46%) when approximately equal numbers of females and juveniles frequented the study area. Our data confirm Diamond's (1972, 1973) reports of unequal roles in chick rearing and post-fledging care between male and female F. magnificens, and support the hypothesis that males and successful females may breed at one- and two-year intervals, respectively.

Kleptoparasitism, the stealing of food from individuals of either the same or a different species, is a common behavior among seabirds. Little is known about the age-related differences in kleptoparasitism behaviors, which may elucidate how this behavior emerged and is maintained in populations. We observed the kleptoparasitic behavior of Fregata magnificens (Magnificent Frigatebirds) on the Dry Tortugas, a group of islands west of Key West, FL. For each kleptoparasitic event, we recorded whether an adult or a sub-adult frigatebird made the attack; whether the potential host was approached while it was in the air, in the water, or on the ground; the duration of the chase; and whether an individual or group of hosts was approached. Adult females most often approached potential hosts in the air (92% of recorded encounters), while sub-adults approached more potential hosts on the ground (61% of recorded encounters). Water approaches were rarely performed by sub-adults and never by adults. Adult fema...

The Gulf of Panama is a highly productive marine ecosystem at the southern edge of North America. Although the Gulf’s aquatic bird populations have been remarked upon by ornithologists for over 50 years, nesting populations have been neither systematically studied nor completely characterized. In 2005 and 2006, the entire Gulf of Panama was inventoried to document the nesting status of seabirds and other colonial waterbirds. Over 50,000 birds of 20 species nesting at 57 sites were documented. Seabirds nested during the dry season, the period of oceanographic upwelling. Coastal colonial waterbirds nested at the end of the dry season and in the early wet season, when inland feeding habitats were optimal. Brown Pelicans (Pelecanus occidentalis) were the most numerous seabird with over 4,800 nests and 10,000 individuals counted. Over 3,600 Neotropic Cormorant (Phalacrocorax brasilianus) nests and over 2,200 Magnificent Frigatebird (Fregata magnificens) nests were documented. Cattle Egrets (Bubulcus i...

The Xisha Archipelago, South China Sea, was surveyed for waterbirds in March-April 2003 and April-August 2004. Forty-five waterbird species were recorded, making a grand total of 53 species for the Archipelago when earlier published records are included. The Archipelago is of great importance for the Red-footed Booby (Sula sula), with an estimated 10% of the world population breeding on Dong Island. Other breeding seabird species were Great Frigatebird (Fregata minor), Great Crested Tern (Sterna bergii) and Sooty Tern (S. fuscata), and it is believed that Black-naped Tern (S. sumatrana) and Roseate Tern (S. dougallii) also breed there. Compared to 1926, the number of seabirds, and the islands on which they breed, has declined greatly. The data for Ardeidae and shorebirds provide information on migration and, possibly, wintering strategies of these species. Despite habitat degradation and human disturbance, the Xisha Archipelago is still important for breeding seabirds and there is an urgent need ...

Annual apparent survival rates of the Magnificent Frigatebird (Fregata magnificens) were estimated from 1998 to 2003 using a capture-resight model with 870 marked adult birds on Isla Isabel, Mexico (21°51’N, 105°54’W). The most parsimonious model was a time since marking model (or two age class model) with constant resighting rate for males and females (pm and pf), constant apparent survival rate for males in both age classes (ϕ1m and ϕ2+m), and time-dependent apparent survival rate for females (ϕ1f and ϕ2+f) in both age classes. We found higher resighting rates in males than in females, a tendency of higher apparent survival in females than in males in 1999, a clear higher apparent survival rates in females than in males in 2000, nearest the same apparent survival rates of the two age classes of males throughout, and differences in apparent survival between age classes of females showing considerable annual variation within age classes. The results suggest permanent emigration of females from th...

Male magnificent frigatebird (Fregata magnificens) ornamentation includes bright iridescent plumage and a red inflatable gular pouch. These signals are displayed during courtship, along with a drumming sound produced through specialized beak clackings resonating in the gular pouch. The extent of white in the plumage identifies three age classes of nonjuvenile male. Here we investigate how morphological and secondary sexual traits correlate with age class and mating status. Even though several age class-related differences in morphology and visual appearance can be identified, the only features that significantly predict mating success are acoustic components of courtship display. Specifically, males that mate drum at lower fundamental frequencies--that is, they have larger gular pouches--and have a quicker and more constant drumming cadence than unsuccessful males. The fundamental frequency decreases with age class, reflecting an increase in gular pouch size. This implies that females prefer older or possibly more experienced or viable males. Drumming cadence speed and stability might reflect male stamina. Apart from the acoustic differences with mating status, there is a nonsignificant tendency for back-feather iridescence to be of shorter reflectance wavelength spectra in mated than in unmated males, which, when combined with acoustic variables, improves prediction of age class and mating status.

The phylogenetic position of the order Spenisciformes in Aves remains unclear despite several independent analyses based on morphological and molecular data. To address this issue, we determined the complete mtDNA sequence of rockhopper penguins. The mitochondrial genome, excluding the region from the D-loop to 12SrRNA, was also sequenced for petrel, albatross, frigatebird, loon and grebe, which previous studies suggest are related to penguins. A maximum likelihood analysis of the phylogenetic placement of penguins with 23 birds, including 17 species whose mtDNA sequences were previously reported, suggested that storks are the closest extant relatives of penguins, with 78% and 56% bootstrap supports, depending on the choice of outgroup species. Thus, ciconiiform birds constitute new candidates as the closest extant relatives of penguins (previously proposed candidates were either gaviiform, podicipediform, or procellariiform birds). In addition to this new evidence, our analysis gave evidence to some of ambiguous relationships in the avian tree: our analysis supported a basal split between passerines and other neoavians within Neoaves, and rejected the monophyly of Falconiformes as well as that of loons and grebes.

Caribbean seabirds are subject to numerous threats, and population levels are thought to be at a fraction of historical levels. Despite being a well-known taxonomic group there is still a paucity of data for most seabird species on many of the Caribbean islands. We carried out detailed surveys of the seabird breeding populations in the British Virgin Islands (BVI) during the breeding seasons of 2004 and 2005. We surveyed 42 different islands and cays over the 2 yr with 60 and 63% of these having at least one breeding seabird species in 2004 and 2005, respectively. A total of 15 spe- cies of breeding seabird was recorded, one of which, the gull-billed tern Sterna nilotica, was pre- viously thought to have been extirpated. Two species, roseate tern Sterna dougallii and magnificent frigatebird Fregata magnificens, had globally significant colonies in the BVI and a further 8 species had a regionally significant population in the BVI. We discuss our findings within a global and regional conservation context and provide recommendations for ensuring the continued existence of BVI seabird populations.

We reviewed the status of the breeding marine birds on San Benedicto Island, Mexico, based on >100 years of published observations and seven of our own surveys conducted between 1978 and 2000. We found that there have been marked changes in the island avifauna with two main trends evident. First, a volcanic eruption destroyed much of the island in 1952. The Wedge-tailed Shearwater (Puffinus pacificus; estimated breeding population 1,000 pairs), Townsend's Shearwater (Puffinus auricularis; probable breeder, small numbers), and Red-footed Booby (Sula sula; 60 pairs) historically had much larger populations, but they apparently never fully recovered from the eruption. The Masked Booby (Sula dactylatra; 2,185 pairs), however, has become much more abundant perhaps due to changes in the vegetation. The second trend is that within the last three decades at least two, and possibly four, species from the central Pacific have colonized the island. The Laysan Albatross (Phoebastria immutabilis; 12 pairs) started breeding in the late 1980s; Black-footed Albatross (Phoebastria nigripes; 1 pair) in 2000. Red-tailed Tropicbirds (Phaethon rubricauda; probable breeder, 10 pairs) may have started breeding in the 1980s, and at least some of the breeding Brown Boobies (Sula leucogaster; 300 pairs) are from central Pacific populations. The reason(s) for this influx of central Pacific species is unknown, but likely involves changes in the marine environment. Other breeding species include the Red-billed Tropicbird (Phaethon aethereus; 200 pairs), Nazca Booby (Sula granti; 50 pairs), Great Frigatebird (Fregata minor; 165 pairs), and Magnificent Frigatebird (Fregata magnificens; 5 pairs).

In this study, we examined the pathophysiological consequences likely to be attributable to a herpesvirus infection for immune function, corticosterone, telomere length and inflammation. We found that the plasma concentration of haptoglobin was strongly associated with the observable clinical manifestation of disease and could predict probabilities of survival., Herpesvirus outbreaks are common in natural animal populations, but little is known about factors that favour the infection and its consequences for the organism. In this study, we examined the pathophysiological consequences of a disease probably attributable to herpesvirus infection for several markers of immune function, corticosterone, telomere length and inflammation. In addition, we assessed whether any markers used in this study might be associated with the occurrence of visible clinical signs of the disease and its impact on short-term survival perspectives. To address our questions, in spring 2015, we collected blood samples from nestlings of the magnificent frigatebird (Fregata magnificens) that were free of any clinical signs or showed visible signs of the disease. We found that the plasma concentration of haptoglobin was strongly associated with the infection status and could predict probabilities of survival. We also found that nestlings with clinical signs had lower baseline corticosterone concentrations and similar telomere length compared with healthy nestlings, whereas we did not find any association of the infection status with innate immune defenses or with nitric oxide concentration. Overall, our results suggest that the plasma concentration of haptoglobin might be a valuable tool to assess survival probabilities of frigatebird nestlings facing a herpesvirus outbreak.

Alcatrazes island and surrounding islets, 35 km from the mainland in southeastern Brazil, are a young archipelago created by rising sea levels around 7,000 years BP. The main island covers 135 ha and is the only to harbour forest, the four islets showing exposed rock, grasses and sedges. A total of 82 species, of which six breeding seabirds, has been recorded in the archipelago. Another 11 seabirds were documented in the waters surrounding the islands. Alcatrazes holds the largest Magnificent Frigatebird, Fregata magnificens, colony in the southern Atlantic, as well as the threatened Brazilian population of Royal Terns, Thalasseus maximus. The landbird community is impoverished, with few resident species but a large number of seasonal visitors, including Atlantic forest species and intertropical and southern migrants.

The Mozambique Channel (western Indian Ocean) is a dynamic environment characterised by strong mesoscale features, which influence all biological components of the pelagic ecosystem. We investigated the distribution, abundance and feeding behaviour of seabirds in the Mozambique Channel in relation to physical and biological environmental variables, with a specific interest in mesoscale features. Seabird censuses were conducted in summer and winter during 7 cruises in the southern and northern Mozambique Channel. Tropical species accounted for 49% of the 37 species identified and 97% of the individuals, and species from the sub-Antarctic region constituted 30% of the identifications. The typically tropical sooty tern (Onychoprion fuscata) was the dominant species during all cruises, and overall accounted for 74% of the species observations and 85% of counted birds. Outputs of Generalised Linear Models at the scale of the Mozambique Channel suggested that higher densities of flying and feeding birds occurred in areas with lower sea surface temperatures and lower surface chlorophyll a concentrations. Most of the flocks of feeding birds did not associate with surface schools of fish or marine mammals, but when they did, these flocks were larger, especially when associated with tuna. While tropical species seemed to favour cyclonic eddies, frontal and divergence zones, non-tropical species were more frequently recorded over shelf waters. Sooty terns foraged preferentially in cyclonic eddies where zooplankton, micronelcton and tuna schools were abundant. Among other major tropical species, frigatebirds (Fregata spp.) predominated in frontal zones between eddies, where tuna schools also frequently occurred and where geostrophic currents were the strongest. Red-footed boobies (Sula sub) concentrated in divergence zones characterised by low sea level anomalies, low geostrophic currents, and high zooplanlcton biomass close to the surface. Our results highlight the importance of mescoscale features in structuring the tropical seabird community in the Mozambique Channel, in addition to segregating tropical and non-tropical species. The mechanisms underlying the segregation of tropical seabirds seem to partially differ from that of other tropical regions, and this may be a consequence of the strong local mesoscale activity, affecting prey size and availability schemes. Beyond characterising the foraging habitats of the seabird community of the Mozambique Channel, this study highlights the importance of this region as a hot spot for seabirds; especially the southern part, where several endangered sub-Antarctic species over-winter.

International audience; Blood parasites of the sub-genus Haemoproteus have been reported in seabirds, in particular in species in the Suliformes order. These parasites are transmitted by hippoboscid flies of the genus Olfersia; strong specificity has been suggested between the vector and its vertebrate host. We investigated the prevalence of Haemoproteus infection in Suliformes and hippoboscid flies in two oceanic islands of the Western Indian Ocean: Europa and Tromelin. In total, 209 blood samples were collected from great frigatebirds (Fregata minor), masked boobies (Sula dactylatra) and red-footed boobies (Sula sula). Forty-one hippoboscid flies were also collected from birds. Seventeen frigatebirds and one fly collected on Europa tested positive for the presence of Haemoproteus parasites by polymerase chain reaction. Phylogenetic analyses based on partial sequences of the Cytochrome b gene showed that parasites were closely related to Haemoproteus iwa reported from frigatebirds in the Pacific Ocean and in the Caribbean. Plasmodium was also detected in a frigatebird on Europa; however, its placement on the phylogenetic tree could not be resolved. We provide strong support for transmission of blood parasites in seabirds in the Western Indian Ocean and suggest that migrations between the Pacific and the Indian oceans could favor the large-scale distribution of Haemoproteus iwa in frigatebird populations.

We discuss the problem of estimating the number of nests of different species of seabirds on North East Herald Cay based on the data from a 1996 survey of quadrats along transects and data from similar past surveys. We consider three approaches based on different plausible models, namely a conditional negative binomial model that allows for additional zeroes in the data, a weighting approach (based on a heteroscedastic regression model), and a transform-both-sides regression approach. We find that the conditional negative binomial approach and a linear regression approach work well but that the transform-both-sides approach should not be used. We apply the conditional negative binomial and linear regression approaches with poststratification based on data quality and availability to estimate the number of frigatebird nests on North East Herald Cay.

Adult female Great Frigatebirds (Fregata minor) were responsible for 64% of the predatory behaviors on Brown Noddy (Anous stolidus) chicks on Tern Island, French Frigate Shoals, Hawaii. Subadults with red orbital rings (presumably females) also preyed on Brown Noddy chicks, although they were observed hunting less frequently than adult females. No adult male frigatebirds were observed hunting in 118.3 hours of observation. Frigatebird predation likely accounted for 95% of mortality observed in Brown Noddy chicks less than 24 days of age. Chicks were as likely to survive to fledging regardless of nest location or down coloration; however, more chicks survived to fledging if hatched between mid-February and mid-May. Unequal sex ratios, sexual size dimorphism, resource partitioning, and breeding strategies of frigatebirds were evaluated to explain why sex differences in frigatebird predation behaviors were observed on Tern Island.

Food stolen from one individual by another, or kleptoparasitism, is known for a variety of bird species and is common in Fregatidae, Laridae, and Stercorariidae (Brockman and Barnard 1979, Furness 1987). Many observations of kleptoparasitism have been made near nesting colonies (Verner 1965, Amerson 1971, Diamond 1975, Nelson 1975, Brockman and Barnard 1979, Gochfeld and Burger 1983, Furness 1987, Osorno et al. 1992, Gilardi 1994, Vickery and Brooke 1994). Nelson (1975) showed for Great Frigatebirds in the Galapagos, Christmas Island, and elsewhere (Vickery and Brooke 1994, Gilardi 1994), that chases occurred close to seabird colonies when victims returned to their roosting sites with full crops. In Hawaii, female and juvenile Great Frigatebirds capture most of their food directly from the ocean and limited kleptoparasitism is generally thought to be a supplement to their diet (Harrison 1990). In this and other species of frigatebirds, success of kleptoparasitic robberies by adults and subadults is ambiguous. Some suggest the juvenile success rates have been lower or equivalent (Gochfeld and Burger 1983), no different (Osorno et al. 1992), or significantly different from that of the adults (Gilardi 1994). When kleptoparasitic behavior was examined by sex of adult frigatebirds, one sex overwhelmingly performed the attacks (Verner 1965, Nelson 1968, Diamond 1975, Gibbs and Gibbs 1987, Osorno et al. 1992). I examined sex bias of host selection and rates of success in kleptoparasitic robberies by Great Frigatebirds of Wedge-tailed Shearwaters (Puffinus pacificus) and Masked Boobies (Sula dactylatra). I also compared success rates between individual and group robberies.