Puffinus Opisthomelas Research Articles

The Isotopic Pattern Variability in the Breeding and Non-Breeding Black-Vented Shearwater

The Isotopic Pattern Variability in the Breeding and Non-Breeding Black-Vented Shearwater

Individual variability in diving behavior of the Black-vented Shearwater in an ever-changing habitat

Oceanic mesoscale systems are characterized by inherent variability. Climatic change adds entropy to this system, making it a highly variable environment in which marine species live. Being at the higher levels of the food chain, predators maximize their performance through plastic foraging strategies. Individual variability within a population and the possible repeatability across time and space may provide stability in a population facing environmental changes. Therefore, variability and repeatability of behaviors, particularly diving behavior, could play an important role in understanding the adaptation pathway of a species. This study focuses on characterizing the frequency and timing of different dives (termed simple and complex) and how these are influenced by individual and environmental characteristics (sea surface temperature, chlorophyll a concentration, bathymetry, salinity, and Ekman transport). This study is based on GPS and accelerometer-recorded information from a breeding group of 59 Black-vented Shearwater and examine consistency in diving behavior at both individual and sex levels across four different breeding seasons. The species was found to be the best performing free diver in the Puffinus genus with a maximum dive duration of 88 s. Among the environmental variables assessed, a relationship was found with active upwelling conditions enhancing low energetic cost diving, on the contrary, reduced upwelling and warmer superficial waters induce more energetically demanding diving affecting diving performance and ultimately body conditions. The body conditions of Black-vented Shearwaters in 2016 were worse than in subsequent years, in 2016, deepest and longest complex dives were recorded, while simple dives were longer in 2017–2019. Nevertheless, the species' plasticity allows at least part of the population to breed and feed during warmer events. While carry-over effects have already been reported, the effect of more frequent warm events is still unknown.

A novel combination of methods identifies priority conservation areas for an endemic California Current seabird

There are growing pressures on marine biodiversity. Seabirds in particular are one the most-threatened groups. The black-vented shearwater (Puffinus opisthomelas) is endemic to Mexican islands and the only shearwater living its entire life cycle in the California Current System, one of the most productive large marine ecosystems in the world. Marine Protected Areas (MPAs) in this region, however, were designed without consideration of accurate data on seabird distributions. Here, 57 black-vented shearwaters were GPS-tracked from their main breeding colony (95% of the global population) over four seasons (2016–2019) to estimate their at-sea distribution. Two methods were applied to identify priority conservation areas: the approach developed by BirdLife International to identify marine Important Bird and Biodiversity Areas and a method using expectation-maximization binary clustering to identify core foraging areas. One potential marine Important Bird and Biodiversity Area close to the breeding colony and five core foraging areas were identified. These priority conservation areas were largely beyond the bounds of the current MPA network in the region. Our results detail opportunities for improving the implementation of conservation and management measures in the California Current System region with respect to seabirds. The approach of combining site identification methods can be applied to other seabird species for which high-resolution tracking data are available and can help guide conservation action plans and MPA design.

Carry‐over effects of environmental stochasticity of the California Current on body condition and wing length of breeding Black‐vented Shearwaters (Puffinus opisthomelas)

Recent climatic variation has led to a change in size or mass in some species. The Black‐vented Shearwater Puffinus opisthomelas is endemic to the California Current System, a highly variable system, giving us cues as to the effects of interannual variability on predators. Here, we report the results of a comparison of biometrics measurement in the short term, 4 years, with different environmental conditions. We found that environmental variability has a direct effect on the body condition of the species, affecting not only body mass but also wing length, with shorter wings as a carry‐over effect of adverse conditions.

Mercury exposure in relation to foraging ecology and its impact on the oxidative status of an endangered seabird

Mercury is a natural element extensively found in the Earth's crust, released to the atmosphere and waters by natural processes. Since the industrial revolution, atmospheric deposition of Hg showed a three-to-five-fold enrichment due to human activities. Marine top predators such as seabirds are recognized valuable bioindicators of ocean health and sensitive victims of Hg toxic effects. Hg negatively affects almost any aspect of avian physiology; thus, birds prove valuable to study the effect of Hg exposure in vertebrates. The Black-vented Shearwater is endemic to the North-Eastern Pacific Ocean, where it forages along the Baja California Peninsula during the breeding period. The area has no industrial settlement and is in the southern portion of the California Current System (CCS). After observing possible contamination effects in eggshells, we decided to quantify the exposure of breeding birds to Hg and test for possible effects on oxidative status of the species. The concentration of Hg in erythrocytes averaged 1.84 μg/g dw and varied from 1.41 to 2.40 μg/g dw. Males and females had similar Hg concentrations. The individual trophic level (reflected by δ15N) did not explain Hg exposure. In contrast, individuals foraging inshore had higher Hg concentrations than those foraging more offshore (reflected by δ13C). Shearwaters having higher concentrations of Hg had lower activity of the antioxidant enzyme glutathione peroxidase and showed lower non-enzymatic antioxidant capacity. Levels of plasma oxidative damage, superoxide dismutase and catalase were not associated with Hg. Our results indicate that (i) the foraging habitat is the factor explaining Hg exposure and (ii) there is some evidence for potential harmful effects of Hg exposure to this seabird species of conservation concern. CapsuleThe foraging habitat is the factor explaining Hg exposure in seabirds and we observed potential harmful effects of Hg exposure in a seabird species of conservation concern.

Tracking reveals behavioural coordination driven by environmental constraints in the Black‐vented Shearwater Puffinus opisthomelas

AbstractDuring the breeding season, seabird foraging trips are constrained by nest attendance schedule and are necessarily colony centred. Oceanographic cues play a major role in the choice of foraging areas to minimize the time spent away from the nest. Here, we analysed the foraging tracks of Black‐vented Shearwaters Puffinus opisthomelas during the incubation and chick‐rearing periods of 2016 and 2017 at Isla Natividad (Mexico). We applied expectation‐maximization binary clustering to track data to clusterize different behaviour patterns during foraging flights. We then applied binary generalized linear mixed models to characterize of foraging areas based on of environmental variables. We finally used kernel estimation techniques to describe main foraging areas. In 2016, breeding shearwaters used two core areas for foraging and resting on the water; the core area delineated by males was located northward from the colony in the Vizcaino Bay and the core area for females was located southward from the colony at the entrance of San Ignacio Lagoon. In 2017, males and females used the same areas with no evident segregation. Our study provided the first information on Black‐vented Shearwater foraging areas during the breeding season and indicated that sexual segregation within coastal waters off the central Baja California Peninsula might be a foraging strategy during years of warmer ocean, likely less productive regimes. Factors including ocean‐climate‐mediated sexual segregation at sea, leading to interannual variation in foraging areas, should be considered when evaluating management actions intended to protect critical foraging habitats for Black‐vented Shearwaters.

A new use of technology to solve an old problem: Estimating the population size of a burrow nesting seabird.

Estimating the population of burrow-nesting seabirds is a challenging task, as human presence in the colony creates disturbances and can damage burrows and occupants. Here, we present a novel method using aerial photographs taken with Unmanned Aerial Vehicles (UAVs) to estimate the population size of a burrow-nesting seabird, the Black-vented Shearwater (Puffinus opisthomelas), on Natividad Island, Mexico. Our results provide a census of burrows in the colony, with very low detection error (5.6%). This is greater accuracy compared to other methods based on extrapolating results from sample plots to total colony area. We then combined this burrow census with ground truth data on occupancy to estimate population size. We obtained a population estimate of 37,858 and 46,322 breeding pairs for 2016 and 2017 respectively. The proposed method provides a cost effective and repeatable approach for monitoring numbers of burrows occupied in a colony, thereby enabling easier and faster estimates of population trends. We suggest this method can be valid for other burrow-nesting species in habitats without dense vegetation cover.

Observaciones de leucismo en cuatro especies de aves acuáticas en Guerrero Negro, Baja California Sur, México

We report the occurrence of plumage pigment aberrations in 4 species of waterbirds in Baja California Sur: Egretta rufescens, Larus occidentalis, Podiceps nigricollis, Puffinus opisthomelas. These observations represent the first leucistic records for these species for Mexico. The documentation of such cases can help to understand the impact of chromatic aberrations, and their variation between different groups of birds.

Shearwaters as ecosystem indicators: Towards fishery-independent metrics of fish abundance in the California Current

Shearwaters are ideal for monitoring ocean conditions in the California Current because these predators are abundant, conspicuous, and responsive to oceanographic variability. Herein we evaluated black-vented (Puffinus opisthomelas), Buller's (P. bulleri), flesh-footed (P. carneipes), pink-footed (P. creatopus), short-tailed (P. tenuirostris), and sooty (P. griseus) shearwaters as fishery-independent indicators of predatory or prey fish availability. We analyzed four years (1996, 2001, 2005, 2008) of monthly (August–November) National Oceanic and Atmospheric Administration seabird surveys, and United States Geological Survey Pacific Coast Fisheries Database catch, from the California coast to 200nm offshore. An ordination of shearwater abundance and fish catch revealed that the shearwaters and 11 fish/squid species were significantly correlated with one or more of three principal components, which explained 86% of the variation and revealed distinct species assemblages. We evaluated multiple linear regression models for 19 fisheries using five shearwater metrics: density, aggregation, and behavior (traveling, stationary, feeding), three oceanographic indices, and latitude. Eight of these models had a shearwater metric as the primary predictor. In particular, feeding black-vented shearwater abundance explained 75% of dolphinfish (Coryphaena hippurus) longline catch. This research illustrates the utility of shearwaters as ecosystem indicators, with direct application for predicting fishery catch of commercial importance.

Breeding biology and conservation of the Black‐vented Shearwater Puffinus opisthomelas

The Black‐vented Shearwater Puffinus opisthomelas is endemic to the Pacific coast of Baja California, Mexico. We studied the breeding biology of this species at Natividad Island in 1997 and 1998. The colony at Natividad Island covers approximately 2.5 km2 and we estimated there to be 114 455 (± 27 520 95% CI) burrows in the colony. In 1997 burrow occupancy was 66.9%, providing a population estimate of 76 570 (± 18 411 95% CI) breeding pairs, representing about 95% of the world's population of this species. In 1997 the peak in egg laying occurred in early March and hatching began on 7 May. The incubation period averaged 51 days (± 6 sd) and chick rearing averaged 69 days (± 3 sd). In 1998 burrow occupancy was lower (19.6%) and nest initiation was later (peak egg laying in mid‐April), perhaps a result of El Niño conditions that prevailed in the Eastern Pacific at that time. We calculated that the development of the town and roads on Natividad Island have destroyed over 15% (26 532 burrows) of the breeding habitat on the island.

The effect of feral cats on the population viability of black‐vented shearwaters (Puffinus opisthomelas) on Natividad Island, Mexico

AbstractInsular breeding seabirds are likely to be particularly vulnerable to introduced mammalian predators because they often lack behavioural, morphological and life‐history defenses against predation. We studied the life‐history of the black‐vented shearwater (Puffinus opisthomelas) on Natividad Island, Baja California Sur, Mexico, to examine its vulnerability to introduced feral cats. Using an allometric equation, we estimated that feral cats consumed 328 g of food day‐1 to satisfy their nutritional requirements. We used stable isotope analysis of cat scat to estimate that 90% of the cats' diet was composed of shearwaters. Using data from our focal species and from the closely related manx shearwater (Puffinus puffinus), we created a demographic model to evaluate the effects of cat population size on the annual growth rate (λ) of the shearwater. The annual growth rate for black‐vented shearwaters was estimated to be 1.006 in the absence of cat predation. With predation, we estimated that annual growth rate declined approximately 5% for every 20 cats in a population of 150,000 birds. Persistence times of bird colonies decreased both with an increase in the size of the feral cat population and with a decrease in the size of the initial bird population.

Dive Depth and Diet of the Black-Vented Shearwater (Puffinus opisthomelas)

Dive Depth and Diet of the Black-Vented Shearwater (Puffinus opisthomelas)

Dive Depth and Diet of the Black-vented Shearwater (Puffinus opisthomelas)

Dive Depth and Diet of the Black-vented Shearwater (Puffinus opisthomelas)

Dive Depth and Diet of the Black-vented Shearwater (Puffinus opisthomelas)

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History and Status of Introduced Mammals and Impacts to Breeding Seabirds on the California Channel and Northwestern Baja California Islands

-The California Channel Islands, U.S.A., and Northwestern Baja California Islands, Mexico, host important breeding populations of several seabird species, including the endemic Black-vented Shearwater (Puffinus opisthomelas) and Xanntus' Murrelet (Synthliboramphus hypoleucus). Mammals introduced to nearly all of the islands beginning in the late 1800s to early 1900s include: cats (Felis catus), dogs (Canisfamiliaris), Black Rats (Rattus rattus), rabbits and hares (Leporidae), goats (Capra hirca), sheep (Ovis aries), and other grazers. Cats, dogs and rats are seabird predators, grazers such as goats and sheep cause habitat degredation, and rabbits destroy habitat and compete with hole-nesting seabirds. Cats, which were introduced to at least 19 islands and currently occur on ten islands, have had the greatest impacts on seabirds, including the extinction of the endemic Guadalupe Storm-Petrel (Oceanodroma macrodactyla). Cats are known to have eliminated or severely reduced colonies of Black-vented Shearwaters, Cassin's Auklets (Ptychoramphus aleuticus) and Xantus' Murrelets. Black Rats have occurred on a minimum of seven islands and have reduced numbers of small, hole-nesting alcids on at least one island. At many islands, defoliation and erosion caused by rabbits and large grazing mammals has been severe. Their effects on seabirds are not well documented but potentially are serious. Impacts from introduced mammals have been most severe on islands with no native mammalian predators. On the Northwestern Baja California Islands, temporary and permanent human settlements have led to a greater diversity and source of introductions. Programs to remove introduced mammals and to reduce the possibility of future introductions are needed to restore seabird populations and to preserve the biodiversity of the region. Surveys are needed particularly on the Northwestern Baja California Islands to update the status and distribution of seabirds and to further assess impacts from introduced mammals. Received 18 May 1998, accepted 20 July 1998.

The occurrence of shearwaters (Puffinusspp.) off the west coast of Canada

Shearwaters, Puffinus spp., were studied off the west coast of Canada from 1975 to 1978. Sooty shearwaters, P. griseus, were the most abundant shearwaters off British Columbia in both May and September–October. Pink-footed shearwaters, P. creatopus, also occurred in both spring and fall. Flesh-footed shearwaters, P. carneipes, were found only in May. Buller's shearwaters, P. bulleri, were encountered in June and July during cruises across the Gulf of Alaska and in September and October off British Columbia. The recent increase of Buller's shearwater in the North Pacific is documented. A review of records of the short-tailed shearwater, P. tenuirostris, shows that it is usually rare and irregular off the coast of British Columbia. One black-vented shearwater, P. opisthomelas, was seen in the Gulf of Alaska. Sooty shearwaters occur off British Columbia in far lower numbers than off northern California, Oregon or Washington State. The manner in which sooty shearwaters migrate is described. The relationship between shearwater distributions and depths of water over the continental shelf are examined.

Olfactory perception and bulbar electrical activity in several avian species

Our earlier work on the olfactory responses of pigeons has been extended to six other species of birds, viz., canary ( Serinus canaris), bobwhite quail ( Colinus virginianus virginianus), mallard duck ( Anas platyrhynchos), turkey vulture ( Cathartes aura), raven ( Corvus corax), and blackvented shearwater ( Puffinus puffinus opisthomelas). Heart rate and respiration were monitored in all of these forms during presentation of olfactory stimuli of pure air or bright light. In all but raven, canary and quail, the electrical activity of the olfactory bulb was also recorded through permanently implanted electrodes. Amyl acetate, pyridine, and trimethylpentane were used as olfactory stimuli with all species; the vulture and shearwaters were also tested with natural stimuli of decayed meat and ground fish, respectively. Olfactory bulb electrical activity showed characteristic vertebrate components such as inspiration-linked intrinsic spindles in the frequency range between 20 and 40 Hz, a large ac spike at the onset of odor stimulation that probably corresponds to the electro-bulbo-olfactogram of dc recording, and desynchronization as a result of visual stimulation during a period of relaxation. No consistent species differences were seen. Responses to amyl acetate and trimethylpentane were characteristically different across species. All forms but the raven showed significant somatic responses to some, but not all, of the odorous stimuli presented. Surprisingly, the raven failed to show such responses even to the visual stimulus. The somatic responses were more reliable in species with larger olfactory bulbs, such as the ducks and shear-waters, but were found in birds with extremely small bulbs as well. It seems fair to say that perceptual capacity for olfactory stimuli is likely to exist in all avian species but may differ widely in amount and significance.