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Full-Text Articles in Life Sciences
Contemporary And Historical Separation Of Transequatorial Migration Between Genetically Distinct Seabird Populations, M J. Rayner, M E. Hauber, T E. Steeves, H A. Lawrence, D R. Thompson, P M. Sagar, S J. Bury, R A. Phillips, T J. Landers, L Ranjard, Scott A. Shaffer
Contemporary And Historical Separation Of Transequatorial Migration Between Genetically Distinct Seabird Populations, M J. Rayner, M E. Hauber, T E. Steeves, H A. Lawrence, D R. Thompson, P M. Sagar, S J. Bury, R A. Phillips, T J. Landers, L Ranjard, Scott A. Shaffer
Scott A. Shaffer
Pelagic seabirds are highly mobile, reducing the likelihood of allopatric speciation where disruption of gene flow between populations is caused by physically insurmountable, extrinsic barriers. Spatial segregation during the non-breeding season appears to provide an intrinsic barrier to gene flow among seabird populations that otherwise occupy nearby or overlapping regions during breeding, but how this is achieved remains unclear. Here we show that the two genetically distinct populations of Cook's petrel (Pterodroma cookii) exhibit transequatorial separation of non-breeding ranges at contemporary (ca. 2–3 yrs) and historical (ca. 100 yrs) time scales. Segregation during the non-breeding season per se appears as …
Shearwater Foraging In The Southern Ocean: The Roles Of Prey Availability And Winds, B Raymond, Scott A. Shaffer, S Sokolov, E Woehler, D P. Costa, L Einoder, M Hindell, G Hosie, M Pinkerton, P M. Sagar, D Scott, A Smith, D R. Thompson, C Vertigan, H Weimerskirch
Shearwater Foraging In The Southern Ocean: The Roles Of Prey Availability And Winds, B Raymond, Scott A. Shaffer, S Sokolov, E Woehler, D P. Costa, L Einoder, M Hindell, G Hosie, M Pinkerton, P M. Sagar, D Scott, A Smith, D R. Thompson, C Vertigan, H Weimerskirch
Scott A. Shaffer
Background Sooty (Puffinus griseus) and short-tailed (P. tenuirostris) shearwaters are abundant seabirds that range widely across global oceans. Understanding the foraging ecology of these species in the Southern Ocean is important for monitoring and ecosystem conservation and management. Methodology/Principal Findings Tracking data from sooty and short-tailed shearwaters from three regions of New Zealand and Australia were combined with at-sea observations of shearwaters in the Southern Ocean, physical oceanography, near-surface copepod distributions, pelagic trawl data, and synoptic near-surface winds. Shearwaters from all three regions foraged in the Polar Front zone, and showed particular overlap in the region around 140°E. Short-tailed shearwaters …
Niche Partitioning Among And Within Sympatric Tropical Seabirds Revealed By Stable Isotope Analysis, H S. Young, D J. Mccauley, R Dirzo, R D. Dunbar, Scott A. Shaffer
Niche Partitioning Among And Within Sympatric Tropical Seabirds Revealed By Stable Isotope Analysis, H S. Young, D J. Mccauley, R Dirzo, R D. Dunbar, Scott A. Shaffer
Scott A. Shaffer
The low productivity and unpredictable nature of resources in tropical waters would appear to make resource partitioning among predators difficult. Yet, stable isotope data from the present study suggest that substantial resource partitioning occurs among tropical seabird communities, both between and within species. In the present study, we compared δ13C and δ15N levels among 8 sympatric tropical seabird species. For a subset of these species, we also examined isotopic levels across years, breeding periods, and sexes. When breeding and non-breeding periods were both considered, we found that all species occupied distinct isotopic niches across at least one time period. Resource …
Bringing Home The Trash: Do Differences In Foraging Lead To Increased Plastic Ingestion In Laysan Albatrosses?, L C. Young, C Vanderlip, D C. Duffy, V Afanasyev, Scott A. Shaffer
Bringing Home The Trash: Do Differences In Foraging Lead To Increased Plastic Ingestion In Laysan Albatrosses?, L C. Young, C Vanderlip, D C. Duffy, V Afanasyev, Scott A. Shaffer
Scott A. Shaffer
When searching for prey, animals should maximize energetic gain, while minimizing energy expenditure by altering their movements relative to prey availability. However, with increasing amounts of marine debris, what once may have been ‘optimal’ foraging strategies for top marine predators, are leading to sub-optimal diets comprised in large part of plastic. Indeed, the highly vagile Laysan albatross (Phoebastria immutabilis) which forages throughout the North Pacific, are well known for their tendency to ingest plastic. Here we examine whether Laysan albatrosses nesting on Kure Atoll and Oahu Island, 2,150 km apart, experience different levels of plastic ingestion. Twenty two geolocators were …
Perspectives In Ornithology: Application Of Tracking And Data-Logging Technology In Research And Conservation Of Seabirds, A E. Burger, Scott A. Shaffer
Perspectives In Ornithology: Application Of Tracking And Data-Logging Technology In Research And Conservation Of Seabirds, A E. Burger, Scott A. Shaffer
Scott A. Shaffer
No abstract provided.
Wind, Waves, And Wing Loading: Their Relative Importance To The At-Sea Distribution And Movements Of North And Central Pacific Albatrosses, R M. Suryan, D J. Anderson, Scott A. Shaffer, D D. Roby, Y Tremblay, D P. Costa, F Sato, K Ozaki, G Balogh
Wind, Waves, And Wing Loading: Their Relative Importance To The At-Sea Distribution And Movements Of North And Central Pacific Albatrosses, R M. Suryan, D J. Anderson, Scott A. Shaffer, D D. Roby, Y Tremblay, D P. Costa, F Sato, K Ozaki, G Balogh
Scott A. Shaffer
Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we …
Corticosterone And Foraging Behaviour In A Pelagic Seabird, F Angelier, Scott A. Shaffer, H Weimerskirch, C Trouvé, O Chastel
Corticosterone And Foraging Behaviour In A Pelagic Seabird, F Angelier, Scott A. Shaffer, H Weimerskirch, C Trouvé, O Chastel
Scott A. Shaffer
Because endocrine mechanisms are thought to mediate behavioral responses to changes in the environment, examining these mechanisms is essential for understanding how long-lived seabirds adjust their foraging decisions to contrasting environmental conditions in order to maximize their fitness. In this context, the hormone corticosterone (CORT) deserves specific attention because of its major connections with locomotor activities. We examined for the first time the relationships between individual CORT levels and measurements of foraging success and behavior using satellite tracking and blood sampling from wandering albatrosses (Diomedea exulans) before (pretrip CORT levels) and after (posttrip CORT levels) foraging trips during the incubation …
Validation Of Water Flux And Body Composition In Glaucous Gulls (Larus Hyperboreus), Scott A. Shaffer, Gabrielsen, G.W., Verreault, J, Costa, D.P
Validation Of Water Flux And Body Composition In Glaucous Gulls (Larus Hyperboreus), Scott A. Shaffer, Gabrielsen, G.W., Verreault, J, Costa, D.P
Scott A. Shaffer
Water influx rates (WIR) measured with tritiated water dilution were compared with direct measures of water and energy intake in glaucous gulls (Larus hyperboreus). Total body water (TBW) measured isotopically was also compared with TBW determined by body composition analysis (BCA) of the same birds. Seventeen wild gulls were captured and studied in outdoor enclosures at Ny-Ålesund, Svalbard, in July 2002. Gulls were hand-fed known quantities of Arctic cod (Boreogadus saida) or given water on the basis of one of four experimental treatments: (A) fasting, (B) fish only, (C) water only, or (D) fish and water. Water and energy content …
A Database For The Study Of Marine Mammal Behavior: Gap Analysis, Data Standardization, And Future Directions, Scott A. Shaffer, D P. Costa
A Database For The Study Of Marine Mammal Behavior: Gap Analysis, Data Standardization, And Future Directions, Scott A. Shaffer, D P. Costa
Scott A. Shaffer
A relational database that contained published information on the diving behavior and/or movement patterns of marine mammals was compiled to facilitate a modeling effort of the Effects of Sound on the Marine Environment (ESME) program. A total of 448 references from reports, books, and peer-reviewed journal articles were obtained. The metadata describing each animal studied, location of the study, and equipment used were entered into the database as well as empirical data describing the diving behavior and movement patterns of each animal. In total, the database contained 1815 entries from 51 different marine mammal species or subspecies. The majority of …
Interpolation Of Tracking Data In A Fluid Environment, Y Tremblay, Scott A. Shaffer, S L. Fowler, C E. Kuhn, B I. Mcdonald, M J. Weise, C -A Bost, H Weimerskirch, D E. Crocker, M E. Goebel, D P. Costa
Interpolation Of Tracking Data In A Fluid Environment, Y Tremblay, Scott A. Shaffer, S L. Fowler, C E. Kuhn, B I. Mcdonald, M J. Weise, C -A Bost, H Weimerskirch, D E. Crocker, M E. Goebel, D P. Costa
Scott A. Shaffer
Interpolation of geolocation or Argos tracking data is a necessity for habitat use analyses of marine vertebrates. In a fluid marine environment, characterized by curvilinear structures, linearly interpolated track data are not realistic. Based on these two facts, we interpolated tracking data from albatrosses, penguins, boobies, sea lions, fur seals and elephant seals using six mathematical algorithms. Given their popularity in mathematical computing, we chose Bézier, hermite and cubic splines, in addition to a commonly used linear algorithm to interpolate data. Performance of interpolation methods was compared with different temporal resolutions representative of the less-precise geolocation and the more-precise Argos …
The Comparative Energetics And Growth Strategies Of Sympatric Antarctic And Sub Antarctic Fur Seal Pups, At Iles Crozet, J Py Arnould, S P. Luque, C Guinet, D P. Costa, J Kingston, Scott A. Shaffer
The Comparative Energetics And Growth Strategies Of Sympatric Antarctic And Sub Antarctic Fur Seal Pups, At Iles Crozet, J Py Arnould, S P. Luque, C Guinet, D P. Costa, J Kingston, Scott A. Shaffer
Scott A. Shaffer
The period of maternal dependence is a time during which mammalian infants must optimise both their growth and the development of behavioural skills in order to successfully meet the demands of independent living. The rate and duration of maternal provisioning, post-weaning food availability and climatic conditions are all factors likely to influence the growth strategies of infants. While numerous studies have documented differences in growth strategies at high taxonomic levels, few have investigated those of closely related species inhabiting similar environments. The present study examined the body composition, metabolism and indices of physiological development in pups of Antarctic fur seals …
Heart Rate And Energy Expenditure Of Incubating Wandering Albatrosses: Basal Levels, Natural Variation, And The Effects Of Human Disturbance, H Weimerskirch, Scott A. Shaffer, G Mabille, J Martin, O Boutard, J-L Rouanet
Heart Rate And Energy Expenditure Of Incubating Wandering Albatrosses: Basal Levels, Natural Variation, And The Effects Of Human Disturbance, H Weimerskirch, Scott A. Shaffer, G Mabille, J Martin, O Boutard, J-L Rouanet
Scott A. Shaffer
We studied the changes in heart rate (HR) associated with metabolic rate of incubating and resting adult wandering albatrosses (Diomedea exulans) on the Crozet Islands. Metabolic rates of resting albatrosses fitted with external HR recorders were measured in a metabolic chamber to calibrate the relationship between HR and oxygen consumption (V̇O2) (V̇O2=0.074×HR+0.019, r2=0.567, P<0.001, where V̇O2 is in ml kg–1 min–1 and HR is in beats min–1). Incubating albatrosses were then fitted with HR recorders to estimate energy expenditure of albatrosses within natural field conditions. We also examined the natural variation in HR and the effects of human disturbance on nesting birds by monitoring the changes in HR. Basal HR was positively related to the mass of the individual. The HR of incubating birds corresponded to a metabolic rate that was 1.5-fold (males) and 1.8-fold (females) lower than basal metabolic rate (BMR) measured in this and a previous study. The difference was probably attributable to birds being stressed while they were held in the metabolic chamber or wearing a mask. Thus, previous measurements of metabolic rate under basal conditions or for incubating wandering albatrosses are likely to be overestimates. Combining the relationship between HR and metabolic rate for both sexes, we estimate that wandering albatrosses expend 147 kJ kg–1 day–1 to incubate their eggs. In addition, the cost of incubation was assumed to vary because (i) HR was higher during the day than at night, and (ii) there was an effect of wind chill (<0°C) on basal HR. The presence of humans in the vicinity of the nest or after a band control was shown to increase HR for extended periods (2–3 h), suggesting that energy expenditure was increased as a result of the disturbance. Lastly, males and females reacted differently to handling in terms of HR response: males reacted more strongly than females before handling, whereas females took longer to recover after being handled.
A Comparison Of Methods To Evaluate Energy Expenditure Of Incubating Wandering Albatrosses, Scott A. Shaffer, D P. Costa, H Weimerskirch
A Comparison Of Methods To Evaluate Energy Expenditure Of Incubating Wandering Albatrosses, Scott A. Shaffer, D P. Costa, H Weimerskirch
Scott A. Shaffer
Measurements of incubation energetics can vary depending on the method used to measure metabolism of an incubating bird. Therefore, we evaluated the energy expenditure of six male and four female wandering albatrosses (Diomedea exulans Linnaeus) using doubly labeled water (DLW), the rate of mass loss, and estimates of metabolic water production derived from water influx rate (WIR). Incubation metabolic rates (IMR) determined with DLW ( 169 ± 21 kJ kg d SD) were significantly lower than estimates derived from mass loss ( 277 ± 46kJ kg d SD) and WIR ( males=289 ± 60 kJ kg d vs. females = …