Between 80 000 and 150 000 marine birds wintering in the Bay of Biscay were killed during the "Erika" oil spill. Three complementary studies were conducted to investigate the geographic origins of these birds. The common guillemot, Uria aalge, represented more than 80% of the oiled birds and these studies thus focused primarily on this species. Analyses of 184 ring recoveries and biometry of 1851 corpses indicated that guillemots originated from a large geographic area, including colonies from across the British Isles and the North Sea, along with more northern localities. However, the majority of individuals came from colonies located between western Scotland and the Celtic Sea. The third study, based on a population genetic approach using microsatellite markers (samples from dead oiled birds and from more than 600 birds caught in 19 breeding colonies), showed little genetic differentiation among northeastern Atlantic guillemot colonies. This result limits the ability to identify the geographic origins of the birds using only DNA samples, but reveals a significant amount of gene flow among colonies. Overall, results indicate the large spatial scale of the oil spill's impact and underline the usefulness of combining multiple approaches to assess the local and regional effects of such accidents.

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-An integrated research program was initiated to evaluate if the European shag Phalacrocorax aristotelis can be used as a robust indicator of the marine environment in Mor Braz, Brittany, France. This program focuses on aspects of the ecology of the shag including its abundance, demography, diet and at-sea distribution measured at three breeding colonies. The annual population growth rate was estimated at 1.01 for the period 1987-2009. The number of breeding pairs (mean: 565) was highly variable from year to year. Part of this interannual variation was explained by variations in sea surface temperature and sea surface height in winter and spring: the number of breeding pairs was negatively related to sea surface temperature and sea surface height. First year, second year and adult survival probabilities were 0.44, 0.76 and 0.81, respectively. Juvenile survival rate varied between colonies, despite the short distances separating these islets. Average productivity was one young fledged per nest, but it varied between years and islets. Density of individuals at sea varied between 1.40 ind.km −2 during the breeding season and 3.08 ind.km −2 after the breeding season had ended. Individuals foraged up to 7 km from the nest and performed on average 2.7 foraging trips per day. The average number of dives deeper than 5 m varied from 126 to 400 per day. Mean diving depth, dive duration and time spent at bottom were 13 m, 28 s, and 19 s respectively. Regurgitated pellets were collected regularly. Four fish families (Gadidae, Gobiidae, Atherinidae and Labridae) represented more than 65% of the preys throughout the year, a percentage reaching more than 95% of the prey from May to October. The other fish in the diet were Cottidae, Ammodytidae, and Clupeidae. The diet of the European shag consisted of benthic fish throughout the year, and also included pelagic fish more frequently between June and October. The synchronous variations of productivity between colonies suggest that some common environmental factors affect this demographic parameter at the regional scale. Thus, the European shag has a good potential for being a reliable ecological indicator of the state of this marine environment. Finally, improved knowledge on the foraging ecology of shags will be useful in the process of designing Marine Protected Areas in the Mor Braz to help ensure sustainable management of marine resources and biodiversity conservation.

SummaryWe evaluated three different transect-based survey techniques and one remote sensing technique to census Aleutian Terns (Onychoprion aleutica) at a breeding colony on Black Sand Spit near Yakutat, Alaska. We took vertical low attitude aerial photos of the colony. Terns were counted from aerial images manually and using automated software. Two observer-teams walked a transect through the colony. Observers recorded perpendicular distance from the transect to each chick, nest scrape, egg shell, and occupied nest (nest with eggs) detected. Population estimates were generated from the transect post hoc using the strip transect method, the variable-area transect method (VAT) and distance sampling (program DISTANCE). Aerial photo interpretation was unsatisfactory because, although terns were clearly detectable, many features could not be positively accepted as terns. Automated interpretation of imagery yielded too many false positives resembling terns in size and spectral characteristics to be of further utility. Among the 3 ground survey techniques, distance sampling provided the most robust population estimate (coefficient of variation of 12.9), whereas VAT and strip transects yielded highly variable estimates. In mixed colonies where species composition ratios are also known, distance sampling for occupied nests can be applied as an inexpensive, statistically valid, and repeatable method to monitor tern populations at colony sites.