70 research outputs found
Individual winter movement strategies in two species of Murre (Uria spp.) in the Northwest Atlantic
Individual wintering strategies and patterns of winter site fidelity in successive years are highly variable among seabird species. Yet, an understanding of consistency in timing of movements and the degree of site fidelity is essential for assessing how seabird populations might be influenced by, and respond to, changing conditions on wintering grounds. To explore annual variation in migratory movements and wintering areas, we applied bird-borne geolocators on Thick-billed Murres (Uria lomvia, n = 19) and Common Murres (U. aalge, n = 20) from 5 colonies in the Northwest Atlantic for 2â4 consecutive years. Thick-billed Murres ranged widely and among-individual wintering strategies were highly variable, whereas most Common Murres wintered relatively near their colonies, with among-individual variation represented more by the relative use of inshore vs. offshore habitat. Within individuals, some aspects of the wintering strategy were more repeatable than others: colony arrival and departure dates were more consistent by individual Common than Thick-billed Murres, while the sizes of home ranges (95% utilization distributions) and distances travelled to wintering area were more repeatable for both species. In consecutive years, individual home ranges overlapped from 0â64% (Thick-billed Murres) and 0â95% (Common Murres); and the winter centroids were just 239 km and 169 km apart (respectively). Over the 3â4 year timescale of our study, individuals employed either fixed or flexible wintering strategies; although most birds showed high winter site fidelity, some shifted core ranges after 2 or 3 years. The capacity among seabird species for a combination of fidelity and flexibility, in which individuals may choose from a range of alternative strategies, deserves further, longer term attention
Miniaturized data loggers and computer programming improve seabird risk and damage assessments for marine oil spills in Atlantic Canada
Obtaining useful information on marine birds that can aid in oil spill (and other hydrocarbon release) risk and damage assessments in offshore environments is challenging. Technological innovations in miniaturization have allowed archival data loggers to be deployed successfully on marine birds vulnerable to hydrocarbons on water. A number of species, including murres (both Common, Uria aalge, and Thick-billed, U. lomvia) have been tracked using geolocation
devices in eastern Canada, increasing our knowledge of the seasonality and colony-specific nature of their susceptibility to oil on water in offshore hydrocarbon production areas and major shipping lanes. Archival data tags are starting to resolve questions around behaviour of vulnerable seabirds at small spatial scales relevant to oil spill impact modelling, specifically to determine the duration and frequency at which birds fly at sea. Advances in data capture methods using voice activated software have eased the burden on seabird observers who are collecting
increasingly more detailed information on seabirds during ship-board and aerial transects. Computer programs that integrate seabird density and bird behaviour have been constructed, all with a goal of creating more credible seabird oil spill risk and damage assessments. In this paper, we discuss how each of these technological and computing innovations can help define critical inputs into seabird risk and damage assessments, and when combined, can provide a more realistic understanding of the impacts to seabirds from any hydrocarbon release
Exposure-age constraints on the extent, timing and rate of retreat of the last Irish Sea ice stream
We report 23 cosmogenic isotope exposure ages (10Be and 36Cl) relating to the maximum extent and deglaciation chronology of the Irish Sea Ice Stream (ISIS), which drained the SW sector of the last British-Irish Ice Sheet. These show that the ISIS failed to reach the Preseli Hills of North Pembrokeshire yet extended southwards to impinge on northern Isles of Scilly (50°N) during the last glacial maximum. Four samples from western Anglesey demonstrate deglaciation of the southern Irish Sea Basin by c. 20-18 ka, and two from the Llšn Peninsula in northwest Wales, if valid, suggest deglaciation by c. 23-22 ka followed by gradual oscillatory northwards retreat of the ice margin for over 3000 years. An alternative interpretation of our data suggests that ice reached Scilly as late as 22-21 ka then retreated 450 km northwards within the following three millennia, possibly in response to sea level rise and/or intrinsic reorganisation within the last British-Irish Ice Sheet. Samples from upland source areas of the ISIS in NW England and SW Scotland produced exposure ages â¤14.3 ka, suggesting possible persistence of ice in such areas into the Lateglacial Interstade of 14.7-12.9 ka
Employing Predictive Spatial Models to Inform Conservation Planning for Seabirds in the Labrador Sea
Seabirds are vulnerable to incidental harm from human activities in the ocean, and knowledge of their seasonal distribution is required to assess risk and effectively inform marine conservation planning. Significant hydrocarbon discoveries and exploration licenses in the Labrador Sea underscore the need for quantitative information on seabird seasonal distribution and abundance, as this region is known to provide important habitat for seabirds year-round. We explore the utility of density surface modeling (DSM) to improve seabird information available for regional conservation and management decision making. We, (1) develop seasonal density surface models for seabirds in the Labrador Sea using data from vessel-based surveys (2006â2014; 13,783 linear km of surveys), (2) present measures of uncertainty in model predictions, (3) discuss how density surface models can inform conservation and management decision making, and 4) explore challenges and potential pitfalls associated with using these modeling procedures. Models predicted large areas of high seabird density in fall over continental shelf waters (max. ~80 birds¡kmâ2) driven largely by the southward migration of murres (Uria spp.) and dovekies (Alle alle) from Arctic breeding colonies. The continental shelf break was also highlighted as an important habitat feature, with predictions of high seabird densities particularly during summer (max. ~70 birds¡kmâ2). Notable concentrations of seabirds overlapped with several significant hydrocarbon discoveries on the continental shelf and large areas in the vicinity of the southern shelf break, which are in the early stages of exploration. Some, but not all, areas of high seabird density were within current Ecologically and Biologically Significant Area (EBSA) boundaries. Building predictive spatial models required knowledge of Distance Sampling and GAMs, and significant investments of time and computational powerâresource needs that are becoming more common in ecological modeling. Visualization of predictions and their uncertainty needed to be considered for appropriate interpretation by end users. Model uncertainty tended to be greater where survey effort was limited or where predictor covariates exceeded the range of those observed. Predictive spatial models proved useful in generating defensible estimates of seabird densities in many areas of interest to the oil and gas industry in the Labrador Sea, and will have continued use in marine risk assessments and spatial planning activities in the region and beyond
Tracking long-distance migration to assess marine pollution impact
Animal tracking provides new means to assess far-reaching environmental impacts. In the aftermath of the Deepwater Horizon explosion in the Gulf of Mexico, a long-distance migrant, the northern gannet (Morus bassanus) suffered the highest oiling among beach-wrecked birds recovered. Analysis of bird-borne tracking data indicated that 25 per cent of their North American population from multiple colonies in eastern Canada migrated to the pollution zone. Findings contrasted sharply with available mark-recapture (band recovery) data. The timing of movement into and out of the Gulf indicates that immature birds would have absorbed most oil-induced mortality. Consequently, one of two outcomes is likely: either a lagged (likely difficult to assess) population decrease, or an undetectable population response buffered by age-related life-history adaptations. Tracking research is especially useful when little information on animal distributions in pollution zones is available, as is the case in the Gulf of Mexico. Ongoing research highlights current risks and conservation concerns
The impact of IFRS 7 on the significance of Financial Instruments disclosure:evidence from Jordan
Checklist (2003)of the Birds of Insular Newfoundland and its Continental Shelf Waters
This new checklist updates and replaces the Natural History Society of Newfoundland and Labrador publication Checklist
(1999) of the Birds of Insular Newfoundland and its Continental Shelf Waters by B. Mactavish, J.E. Maunder, W.A. Montevecchi and J.L. Wells. A total of 378 species, plus 3 additional subspecies, have been accepted for inclusion by the Bird Records Committee. Nomenclature is in accordance with the American Ornithologistsâ Union Check-list of North American Birds, Seventh Edition (1998) and supplements up to and including the Forty-fourth Supplement to the American Ornithologistsâ Union Check-list of North American Birds (2003).
Ten species are new to the 2003 list, including Fea's Petrel, Brown Pelican, Gray Heron, American Avocet, Gull-billed Tern, White-winged Dove, Red-bellied Woodpecker, Scissor-tailed Flycatcher, Spotted Towhee and Brewer's Blackbird. The list is current to July 31, 2003.
Twelve additional species have been recorded from the neighbouring French Islands of St-Pierre et Miquelon, including Eared Grebe, Yellow Rail, Red-necked Stint, Roseate Tern, Ringed Turtle-Dove, European Turtle-Dove, Whip-poor-will, Common Swift, Common House-Martin, Black-backed Wagtail, Black-throated Sparrow and Eurasian Siskin (Desbrosse, A., R. Etcheberry, and G. Barthe. 1990. Repertoire des oiseaux de lâarchipel. Les cahiers de lâecho [SPM] Avril 1990: 8 pp.; and R. Etcheberry, personal communication, 2003)
Winter areas and migratory tactics of northern gannets (morus bassanus) breeding in North America
Migration has evolved to allow organisms to undertake life history functions in the most appropriate place at the most appropriate time. Migration creates seasonal ecological linkages that have important implications for survival, population dynamics, response to climate change and species conservation. Yet, knowledge of the wintering areas, migratory routes and timing of migration for individual and populations are unknown for most avian species, particularly seabirds. -- This is the first study to electronically track migration and wintering of gannets breeding in North America. Data from band returns and geolocators were integrated to investigate migratory connectivity and the timing and execution of migration in Northern Gannets (Morus bassanus) from four large North American colonies. -- Gannets had distinct wintering areas and aggregated into several major hotspots. Most adults remained along the northeast North American coast closest to their colonies and breeding populations displayed weak migratory connectivity. Unexpectedly, the Gulf of Mexico was revealed to be an important wintering area for adults. Gannets displayed remarkable winter site fidelity with extensive range overlap across years. -- Timing, rates of movement and use of stopovers during migration depended strongly upon winter destination and also upon sex, colony and year. Females departed the colony prior to males in fall but, contrary to prediction, earlier spring arrival of males was not detected. Variation in the ecological constraints operating during different seasons was emphasized by faster and shorter spring migrations in comparison to fall migrations. The repeatability of migratory duration, distance, and timing of arrival and departure from the winter grounds suggested strong individual programs for these traits. However, variability in the timing of colony departure and arrival, migratory speed, and the extent of stopovers en route implies greater involvement of environmental inputs into these behaviours. -- This is the first study to report two strikingly different migration strategies involving trans-Atlantic migration in a continental-shelf migrant seabird. Three gannets displayed a radically different migration and over-winter strategy by undertaking the first recorded (and repeated), wind-assisted, round-trip trans-Atlantic migrations to the coast of Africa, crossing the Atlantic Ocean in as little as five days. The departure timing and routes of west-to-east (and to a lesser extent east-to-west) oceanic crossings were adjusted to maximise the assistance of winds generated by large weather systems; indicating the use of choice in the execution of this remarkable feat for a normally continental shelf migrant. The discovery of this trans-Atlantic connection has implications for interaction, connectivity and phylogeographic radiations between the eastern and western Atlantic populations. -- The observed patterns of migratory timing and scale-dependent connectivity present a novel opportunity to assess the ecological and conservation implications of specific threats during migration and on the wintering grounds. The lability of migratory tactics in the population as a whole combined with remarkable individual consistency in some, but not all, migration parameters offer rare insight into the relative contributions of genetic and environmental factors controlling migration
Examining the nature of the gains from investment in the emerging stock markets of the Central and Eastern European region
This article examines the nature of any gains from investing in the emerging stock markets of Central and Eastern Europe using disaggregated data for 187 shares from eight stock exchanges over the period 1998 to 2003. The results suggest that gains exist; these gains are largest when diversification occurs across countries rather than via investment in different industries. However, the analysis also suggests that the returns earned by equities in these countries vary dramatically over time and, as such, may hamper the efforts of investors attempting to exploit this diversification 'free lunch'.
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