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- Publications (13)
- Biologging (3)
- Foraging behavior (3)
- Activity patterns (2)
- Albatross (2)
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- Black-footed albatross (2)
- Body temperature (2)
- Geolocation (2)
- Inter-individual variation (2)
- Laysan albatross (2)
- Non-breeding (2)
- Satellite tracking (2)
- Seabirds (2)
- Activity budget (1)
- Albatrosses (1)
- Antioxidant (1)
- Behavioral plasticity (1)
- Behaviour (1)
- Bering Sea (1)
- Bivalve (1)
- Black-legged kittiwake (1)
- Byesian modeling (1)
- Central-place forager (1)
- Cerorhinca monocerata (1)
- Climate (1)
- Coexistence (1)
- Colony (1)
- Distribution (1)
- Doubly labeled water (1)
- Energetics (1)
Articles 1 - 25 of 25
Full-Text Articles in Biology
Variable Utilization Of Shelf Break-Associated Habitats By Chick-Brooding Rhinoceros Auklets In The California Current System, Bradley Wilkinson, Jaime Jahncke, Pete Warzybok, Russell Bradley, Scott A. Shaffer
Variable Utilization Of Shelf Break-Associated Habitats By Chick-Brooding Rhinoceros Auklets In The California Current System, Bradley Wilkinson, Jaime Jahncke, Pete Warzybok, Russell Bradley, Scott A. Shaffer
Faculty Publications, Biological Sciences
Identifying frequently complex and dynamic spatial distributions of marine predators via the modeling of at-sea observations can be inherently challenging, especially when attempting to predict habitats of specific populations. Remotely-sensed tracking devices provide a viable alternative way to gather this information. We collected fine-scale spatiotemporal movement data for a small seabird, the rhinoceros auklet Cerorhinca monocerata, in the California Current System. Chick-brooding adults nesting on Southeast Farallon Island were outfitted with GPS loggers during the 2015 and 2016 breeding seasons (n = 15). Along with basic movement parameters, kernel density and residence time analyses were conducted to characterize at-sea distribution …
Foraging Behavior And Energetics Of Albatrosses In Contrasting Breeding Environments, Michelle Antolos, Scott Shaffer, Henri Weimerskirch, Yann Tremblay, Daniel Costa
Foraging Behavior And Energetics Of Albatrosses In Contrasting Breeding Environments, Michelle Antolos, Scott Shaffer, Henri Weimerskirch, Yann Tremblay, Daniel Costa
Faculty Publications, Biological Sciences
Animals can maximize fitness by optimizing energy acquisition through the selection of favorable foraging habitats, but trade-offs exist between time spent in preferred feeding habitats, energetic costs of travel, and reproductive constraints. For pelagic seabirds, geographic distribution of suitable breeding islands can restrict access to marine prey resources and influence foraging strategies. Laysan (Phoebastria immutabilis) and black-footed albatrosses (P. nigripes) breeding in the Northwest Hawaiian Islands, and Indian yellow-nosed albatrosses (Thalassarche carteri) breeding in the Southern Indian Ocean, utilize productive subtropical-subpolar transition zones during their breeding and non-breeding periods, but this marine feature is at a comparatively greater distance for …
Thermal History And Gape Of Individual Mytilus Californianus Correlate With Oxidative Damage And Thermoprotective Osmolytes, Lani Gleason, Luke Miller, Jacob Winnikoff
Thermal History And Gape Of Individual Mytilus Californianus Correlate With Oxidative Damage And Thermoprotective Osmolytes, Lani Gleason, Luke Miller, Jacob Winnikoff
Faculty Publications, Biological Sciences
The ability of animals to cope with environmental stress depends – in part – on past experience, yet knowledge of the factors influencing an individual's physiology in nature remains underdeveloped. We used an individual monitoring system to record body temperature and valve gaping behavior of rocky intertidal zone mussels (Mytilus californianus). Thirty individuals were selected from two mussel beds (wave-exposed and wave-protected) that differ in thermal regime. Instrumented mussels were deployed at two intertidal heights (near the lower and upper edges of the mussel zone) and in a continuously submerged tidepool. Following a 23-day monitoring period, measures of …
Multimodal In Situ Datalogging Quantifies Inter-Individual Variation In Thermal Experience And Persistent Origin Effects On Gaping Behavior Among Intertidal Mussels (Mytilus Californianus), Luke P. Miller, Wesley Dowd
Multimodal In Situ Datalogging Quantifies Inter-Individual Variation In Thermal Experience And Persistent Origin Effects On Gaping Behavior Among Intertidal Mussels (Mytilus Californianus), Luke P. Miller, Wesley Dowd
Faculty Publications, Biological Sciences
In complex habitats, environmental variation over small spatial scales can equal or exceed larger-scale gradients. This small-scale variation may allow motile organisms to mitigate stressful conditions by choosing benign microhabitats, whereas sessile organisms may rely on other behaviors to cope with environmental stresses in these variable environments. We developed a monitoring system to track body temperature, valve gaping behavior and posture of individual mussels (Mytilus californianus) in field conditions in the rocky intertidal zone. Neighboring mussels' body temperatures varied by up to 14°C during low tides. Valve gaping during low tide and postural adjustments, which could theoretically lower …
Individual-Level Variation And Higher-Level Interpretations Of Space Use In Wide-Ranging Species: An Albatross Case Study Of Sampling Effects, Sarah Gutowsky, Marty Leonard, Melinda Conners, Scott A. Shaffer, Ian Jonsen
Individual-Level Variation And Higher-Level Interpretations Of Space Use In Wide-Ranging Species: An Albatross Case Study Of Sampling Effects, Sarah Gutowsky, Marty Leonard, Melinda Conners, Scott A. Shaffer, Ian Jonsen
Faculty Publications, Biological Sciences
Marine ecologists and managers need to know the spatial extent of at-sea areas most frequented by the groups of wildlife they study or manage. Defining group-specific ranges and distributions (i.e., space use at the level of species, population, age-class, etc.) can help to identify the source or severity of common or distinct threats among different at-risk groups. In biologging studies, this is accomplished by estimating the space use of a group based on a sample of tracked individuals. A major assumption of these studies is consistency in individual movements among members of a group. The implications of scaling up individual-level …
Wintering North Pacific Black-Legged Kittiwakes Balance Spatial Flexibility And Consistency, Rachael Orben, Rosana Paredes, Daniel Roby, David Irons, Scott A. Shaffer
Wintering North Pacific Black-Legged Kittiwakes Balance Spatial Flexibility And Consistency, Rachael Orben, Rosana Paredes, Daniel Roby, David Irons, Scott A. Shaffer
Faculty Publications, Biological Sciences
Background Marine environments are inherently dynamic, yet marine predators are often long-lived and employ strategies where consistency, individual specialization, routine migrations, and spatial memory are key components to their foraging and life-history strategies. Intrinsic determinates of animal movements are linked to physiological and life-history traits (e.g. sex, colony, experience), while extrinsic influences occur as the result of an animal’s interactions with either other animals or the environment (e.g. prey availability, weather, competition). Knowledge of the factors affecting animal movements is critical to understand energetic bottlenecks and population dynamics. Here, we attempt to understand the interaction of some of these factors …
Foraging Behavior Links Climate Variability And Reproduction In North Pacific Albatrosses, Lesley Thorne, Elliott Hazen, Steven Bograd, David Foley, Melinda Conners, Michelle Kappes, Hyemi Kim, Daniel Costa, Yann Tremblay, Scott A. Shaffer
Foraging Behavior Links Climate Variability And Reproduction In North Pacific Albatrosses, Lesley Thorne, Elliott Hazen, Steven Bograd, David Foley, Melinda Conners, Michelle Kappes, Hyemi Kim, Daniel Costa, Yann Tremblay, Scott A. Shaffer
Faculty Publications, Biological Sciences
Background: Climate-driven environmental change in the North Pacific has been well documented, with marked effects on the habitat and foraging behavior of marine predators. However, the mechanistic linkages connecting climate-driven changes in behavior to predator populations are not well understood. We evaluated the effects of climate-driven environmental variability on the reproductive success and foraging behavior of Laysan and Black-footed albatrosses breeding in the Northwest Hawaiian Islands during both brooding and incubating periods. We assessed foraging trip metrics and reproductive success using data collected from 2002–2012 and 1981–2012, respectively, relative to variability in the location of the Transition Zone Chlorophyll Front …
Reproductive Constraints Influence Habitat Accessibility, Segregation, And Preference Of Sympatric Albatross Species, Michelle Kappes, Scott Shaffer, Yann Tremblay, David Foley, Daniel Palacios, Steven Bograd, Daniel Costa
Reproductive Constraints Influence Habitat Accessibility, Segregation, And Preference Of Sympatric Albatross Species, Michelle Kappes, Scott Shaffer, Yann Tremblay, David Foley, Daniel Palacios, Steven Bograd, Daniel Costa
Faculty Publications, Biological Sciences
The spatiotemporal distribution of animals is dependent on a suite of factors, including the distribution of resources, interactions within and between species, physiological limitations, and requirements for reproduction, dispersal, or migration. During breeding, reproductive constraints play a major role in the distribution and behavior of central place foragers, such as pelagic seabirds. We examined the foraging behavior and marine habitat selection of Laysan (Phoebastria immutabilis) and black-footed (P. nigripes) albatrosses throughout their eight month breeding cycle at Tern Island, Northwest Hawaiian Islands to evaluate how variable constraints of breeding influenced habitat availability and foraging decisions. We used satellite tracking and …
Shadowed By Scale: Subtle Behavioral Niche Partitioning In Two Sympatric, Tropical Breeding Albatross Species, Melinda Conners, Elliott Hazen, Daniel Costa, Scott A. Shaffer
Shadowed By Scale: Subtle Behavioral Niche Partitioning In Two Sympatric, Tropical Breeding Albatross Species, Melinda Conners, Elliott Hazen, Daniel Costa, Scott A. Shaffer
Faculty Publications, Biological Sciences
Background To meet the minimum energetic requirements needed to support parents and their provisioned offspring, the timing of breeding in birds typically coincides with periods of high food abundance. Seasonality and synchrony of the reproductive cycle is especially important for marine species that breed in high latitudes with seasonal booms in ocean productivity. Laysan and black-footed albatrosses breeding in the northwestern Hawaiian Islands have a dual reliance on both seasonally productive waters of high latitudes and on nutrient-poor waters of low latitudes, because their foraging ranges contract during the short but critical brood-guard stage. Therefore, these species face an additional …
Daily Activity Budgets Reveal A Quasi-Flightless Stage During Non-Breeding In Hawaiian Albatrosses, Sarah Gutowsky, Lee Gutowsky, Ian Jonsen, Marty Leonard, Maura Naughton, Marc Romano, Scott A. Shaffer
Daily Activity Budgets Reveal A Quasi-Flightless Stage During Non-Breeding In Hawaiian Albatrosses, Sarah Gutowsky, Lee Gutowsky, Ian Jonsen, Marty Leonard, Maura Naughton, Marc Romano, Scott A. Shaffer
Faculty Publications, Biological Sciences
Background Animals adjust activity budgets as competing demands for limited time and energy shift across life history phases. For far-ranging migrants and especially pelagic seabirds, activity during breeding and migration are generally well studied but the “overwinter” phase of non-breeding has received less attention. Yet this is a critical time for recovery from breeding, plumage replacement and gaining energy stores for return migration and the next breeding attempt. We aimed to identify patterns in daily activity budgets (i.e. time in flight, floating on the water’s surface and active foraging) and associated spatial distributions during overwinter for the laysan Phoebastria immutabilis …
High Predation On Small Populations: Avian Predation On Imperiled Salmonids, Ann-Marie Osterback, Danielle Frechette, Andrew Shelton, Sean Hayes, Morgan Bond, Scott A. Shaffer, Jonathan Moore
High Predation On Small Populations: Avian Predation On Imperiled Salmonids, Ann-Marie Osterback, Danielle Frechette, Andrew Shelton, Sean Hayes, Morgan Bond, Scott A. Shaffer, Jonathan Moore
Faculty Publications, Biological Sciences
Generalist predators can contribute to extinction risk of imperiled prey populations even through incidental predation. Quantifying predation on small populations is important to manage their recovery, however predation is often challenging to observe directly. Recovery of prey tags at predator colonies can indirectly provide minimum estimates of predation, however overall predation rates often remain unquantifiable because an unknown proportion of tags are deposited off‐colony. Here, we estimated overall predation rates on threatened wild juvenile steelhead Oncorhynchus mykiss by generalist adult Western Gulls Larus occidentalis in six central California (USA) watersheds. We estimated predation rates by gulls from the recapture of …
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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 …
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
Faculty Publications, Biological Sciences
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 …
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
Faculty Publications, Biological Sciences
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 …
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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 …
Extreme Water Velocities: Topographical Amplification Of Wave-Induced Flow In The Surf Zone Of Rocky Shores, Mark Denny, Luke Miller, M. Stokes, L. J. H. Hunt, B. S. T. Helmuth
Extreme Water Velocities: Topographical Amplification Of Wave-Induced Flow In The Surf Zone Of Rocky Shores, Mark Denny, Luke Miller, M. Stokes, L. J. H. Hunt, B. S. T. Helmuth
Faculty Publications, Biological Sciences
Water velocities as high as 25 m s-1 have been recorded in the surf zone of wave-swept rocky shores-velocities more than twice the phase speed of the breaking waves with which they are associated. How can water travel twice as fast as the waveform that initially induces its velocity? We explore the possibility that the interaction of a wave with the local topography of the shore can greatly amplify the water velocities imposed on intertidal plants and animals. Experiments in a laboratory wave tank show that interactions between bores refracted by a prowlike beach can produce jets in which the …
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
Faculty Publications, Biological Sciences
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
Faculty Publications, Biological Sciences
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 = …