Global Location Sensors Research Articles

Effects of geolocation archival tags on reproduction and adult body mass of sooty shearwaters (Puffinus griseus)

We attached 11 g (1.4% body‐mass equivalent) global location sensing (GLS) archival tag packages to tarsi of 25 breeding sooty shearwaters (Puffinus griseus, titi) on Whenua Hou (Codfish Island), New Zealand during the chick‐rearing period in 2005. Compared with chicks reared by non‐handled adults that did not carry tags, deployment of tags on one or both adult parents ultimately resulted in 35% reduction in chick body mass and significantly reduced chick skeletal size preceding fledging (19 April). However, body mass between chick groups was not significantly different after controlling for skeletal size. Effects on chicks were more pronounced in six pairs where both parents carried tags. Chick mass was negatively related to the duration that adults carried tags. In this study, none of the chicks reared by pairs where both parents were tagged, 54% of chicks reared by pairs where one parent was tagged, and 83% of chicks reared by non‐handled and non‐tagged parents achieved a previously determined pre‐fiedging mass threshold (564 g; Sagar & Horning 1998). Body mass of adults carrying tags and returning from trans‐equatorial migration the following year were 4% lighter on average than non‐tagged birds, but this difference was not statistically significant. Reduced mass among chicks reared by adults carrying tags during the chick‐provisioning period indicated that adults altered “normal” provisioning behaviours to maintain their own body condition at the expense of their chicks. Population‐level information derived from telemetry studies can reveal important habitat‐linked behaviours, unique aspects of sea‐bird foraging behaviours, and migration ecology. Information for some species (e.g., overlap with fisheries) can aid conservation and marine ecosystem management. We advise caution, however, when interpreting certain data related to adult provisioning behaviours (e.g., time spent foraging, provisioning rates, etc.). If effects on individuals are of concern, we suggest shorter‐term deployments, smaller and lighter tags, and alternative attachment techniques, especially when investigating threatened or endangered species.

The lunar cycle affects at-sea behaviour in a pelagic seabird, the streaked shearwater, Calonectris leucomelas

The lunar cycle has been shown to affect the behaviour of a variety of marine animals. However, changes in the behaviour of seabirds and marine mammals and how they respond to the lunar cycle have been less well documented, principally because of the technical difficulties in long-term recording of their at-sea behaviour. Because seabirds generally rely on visual cues at small spatial scales, ambient light levels by moonlight may have a strong influence on their foraging and predator avoidance behaviours at sea at night. We used global location sensor loggers attached to wintering streaked shearwaters to examine whether the birds' at-sea behaviour varied with the lunar phase. The shearwaters migrated from Japan to the seas off northern New Guinea. Their activities at night changed synchronously with the lunar phase: birds flew for longer periods and landed on water more frequently on nights with a full moon than when there was a new moon. Our results indicate that at-sea behaviour of pelagic seabirds is closely associated with the lunar cycle.

Utility of geolocating light loggers for indicating at-sea movements in sea turtles

As marine turtles traverse entire ocean basins, a number of techniques have been developed to gather information on their movements at sea. These range from basic methods, such as mark and recapture using flipper tags, to more technically advanced, expensive approaches, such as satellite tracking. Here we report the first published use of geolocation by light, using global location sensing (GLS) units, to estimate the locations of marine turtles in the Mediterranean. We attached units to 9 green Chelonia mydas and 3 loggerhead Caretta caretta turtles which had nested in Cyprus in previous years. One individual of each species was also fitted with a satellite transmitter for comparison. GLS units were retrieved on subsequent visits made by instrumented turtles during the same nesting season. In total, 28 GLS units were recovered from 12 individuals. The mean great-circle distance between the mean daily position calculated from satellite tracking and the corresponding mean light-based geolocation over the same time period was 50.3 km for green turtles and 57.6 km for loggerhead turtles. We suggest that GLS technology offers potential utility for identifying large-scale movements, migratory pathways, and over-wintering or foraging sites of adult female marine turtles.

Effects of Dummy Global Location Sensors on Foraging Behavior of Cook's Petrel (Pterodroma cookii)

The effect of 4.5-g dummy geolocation loggers on the foraging ability of Cook's Petrel (Pterodroma cookii) was assessed over single foraging trips from Little Barrier Island, New Zealand. I compared foraging trip duration and chick provisioning between equipped and unequipped birds and could not detect a detrimental effect of loggers on either parameter. The lack of effect of these loggers may be the result of their small size, the short-term nature of their use, and foraging strategies used by Cook's Petrel. Geolocation studies involving Cook's Petrel and other small gadfly petrel species may be feasible for single foraging trips.

Accuracy of geolocation estimates for flying seabirds

Geolocation (Global Location Sensing or GLS logging) using archival light-recording tags offers considerable potential for tracking animal movements, yet few studies of flying seabirds have exploited this technology. Our study evaluated its effectiveness for determining foraging ranges of black-browed albatrosses Thalassarche melanophrys fitted simultaneously with GLS loggers and satellite-transmitters (Platform Terminal Transmitters, PTTs). After some preliminary validation, the position of an albatross could be determined by geolocation with a mean error +/- SD of 186 +/- 114 km (SDs of 1.66degrees and 1.82degrees of latitude and longitude, respectively). Errors from identical static loggers were lower (mean +/- SD of 85 +/- 47 km, with overall SDs of 0.61degrees and 0.99degrees of latitude and longitude, respectively) and less variable, with the difference attributable to variation in sensor orientation, intermittent shading by plumage, and the difficulty of correcting for extensive, potentially non-linear movements of flying birds. Iterative smoothing reduced both the mean error and the inflation of kernel ranges derived from GLS data, but over-smoothing contracted the extremes of the range. This reduced the overlap with radial cores apparent in the control data, and should be avoided for multinuclear GLS fix distributions. The accuracy of GLS tags is more than adequate for tracking migration and breeding-season foraging ranges of pelagic species, and for identifying broad-scale habitat preferences, overlap and potential conflict with commercial fisheries.

SPATIAL AND TEMPORAL VARIABILITY IN THE FORAGING AREAS OF BREEDING KING PENGUINS

King Penguins (Aptenodytes patagonicus) from breeding islands in the Indian Ocean (Crozet and Kerguelen Islands) and the Atlantic Ocean (South Georgia and Falkland Islands) were equipped with global location sensors to compare their foraging patterns during different times of the year. In summer, all birds investigated traveled toward the Antarctic Polar Front (APF), irrespective of whether they bred to the north (Crozet Islands, Falkland Islands), within (Kerguelen Islands) or to the south (South Georgia) of this hydrographic feature. Whereas most birds remained north of the APF and foraged in waters of the Antarctic Polar Frontal Zone, some penguins also traveled, or remained (South Georgia), south of the APF and foraged in Antarctic waters. It appeared that food resources in the vicinity of the APF were sufficiently predictable to warrant travel of several hundred km by King Penguins for foraging. Data collected on the winter distribution of King Penguins indicated at least two different foraging strategies. Birds from the oceanic Crozet Islands foraged beyond the APF in the Antarctic waters, whereas birds from the Falkland Islands relied also on the resources provided by the highly diverse and productive slope of the Patagonian Shelf. However, despite these differences, in both cases minimum distances of sometimes more than 10 000 km were covered. Further research on the foraging habitats of King Penguins over the entire breeding season and the temporal and spatial changes of oceanographic features is necessary to obtain a comprehensive picture on the variability in the foraging ranges of King Penguins. Variabilidad Espacial y Temporal en las Áreas de Forrajeo de Individuos Reproductivos de Aptenodytes patagonicus Resumen. Comparamos los patrones de forrajeo de individuos reproductivos de Aptenodytes patagonicus provenientes de las islas del Océano Índico (Islas Crozet y Kerguelen) y Océano Atlántico (Islas Georgia del Sur y Malvinas) durante diferentes períodos del año, equipando pingüinos con sensores de localización global. En el verano, todas las aves investigadas viajaron hacia el Frente Polar Antártico (FPA), independientemente de si se reprodujeron al norte (Islas Crozet, Islas Malvinas), en (Islas Kerguelen) o al sur (Islas Georgias del Sur) de aquella entidad hidrográfica. Aunque la mayoría de las aves permanecieron al norte del FPA y forrajearon en aguas de la Zona Polar Frontal Antártica, algunos pingüinos también viajaron hacia el sur del FPA y forrajearon en aguas antárticas. Al parecer los recursos alimenticios en el FPA fueron lo suficientemente predecibles como para justificar que los pingüinos viajen varios cientos de kilómetros para forrajear. Los datos colectados durante la distribución de invierno de A. patagonicus indicaron por lo menos dos estrategias de forrajeo diferentes. Las aves provenientes de las islas oceánicas Crozet forrajearon más allá del FPA en aguas antárticas, mientras que las aves provenientes de las Islas Malvinas dependieron además de los recursos que provee la diversa y productiva plataforma marítima patagónica. Sin embargo, a pesar de estas diferencias, en ambos casos a veces las aves cubrieron distancias mínimas de más de 10 000 km. Para obtener un panorama completo sobre la variabilidad en los rangos de forrajeo de A. patagonicus es necesario efectuar más investigaciones sobre los hábitats de forrajeo de estos pingüinos durante la totalidad de la época reproductiva y durante todos los cambios temporales y espaciales de las entidades hidrográficas.

Black-browed albatrosses, international fisheries and the Patagonian Shelf

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 195:269-280 (2000) - doi:10.3354/meps195269 Black-browed albatrosses, international fisheries and the Patagonian Shelf D. Grémillet1,*, R. P. Wilson2, S. Wanless1, T. Chater3 1Centre for Ecology and Hydrology, Banchory Research Station, Hill of Brathens, Banchory, Kincardineshire AB31 4BY, Scotland, UK 2Institut für Meereskunde Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany 3New Island, Falkland Islands, South Atlantic *E-mail: dgrem@ceh.ac.uk ABSTRACT: Albatrosses have among the most remarkable travelling capacities of any extant animal. However, previous studies regarding their movements at sea have mainly focused on breeding birds commuting between the nest site and offshore feeding grounds. In this study, we compare the movement patterns and at-sea activity of breeding and inter-breeding black-browed albatrosses Diomedea melanophris from the Falkland Islands. Data were recorded via global location and activity sensors for 26 incubating birds (during single foraging trips lasting 6.8 d on average) and 6 inter-breeding individuals (during non-stop offshore journeys of 127.5 d on average). Our results showed that foraging black-browed albatrosses utilise vast offshore areas (the average foraging area was 102000 ± 132000 km2 by incubating birds and 1552000 ± 970000 km2 by inter-breeding birds). However, mean foraging range was similar in both groups (691 ± 330 km and 680 ± 192 km by incubating and inter-breeding birds, respectively) as were their core foraging areas and their at-sea activity patterns. Our results thus indicate that black-browed albatrosses from the Falkland Islands, which represent the largest albatross population world-wide (ca 800000 individuals), mainly rely on marine resources available within the Patagonian Shelf area. Although this highly productive continental shelf is the largest of the Southern Hemisphere, rapid development of industrial fisheries currently results in the removal of over 1.4 million tonnes of fish and squid per year in this zone. As our data also show significant spatio-temporal overlap between human and albatross fishing activities within the Patagonian Shelf, we anticipate major detrimental effects on the albatross population in terms of competition for food and additional mortality caused by bird bycatch. KEY WORDS: Albatross · Global location sensors · Foraging range · Patagonian Shelf · Fisheries Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 195. Publication date: March 31, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.