Burrow-nesting seabirds constitute an important part of seabird diversity, yet accurate estimates of their abundance are largely lacking, limiting our understanding of their population dynamics and conservation status. We conducted a survey to estimate the number of South Georgia diving petrel (Pelecanoides georgicus) burrows during the 2013–14 breeding season on Ile de la Possession, Crozet archipelago, southern Indian Ocean. We used distance sampling and acoustic playback in order to estimate burrow densities in a priori-selected favourable nesting areas. A total of 855 burrows were detected. The mean altitude of burrows was 601.8 ± 69.4 m. The mean burrow detection distance was 1.77 ± 1.63 m. The burrow density was estimated at 15.649 burrows ha-1 (95% confidence interval (CI): 10.245–23.903) and the slope-corrected total favourable area was 2365.53 ha, which yielded an estimate 37 018 burrows (95% CI: 24 235–56 544). The playback response rate was 15.8 ± 1.3%, and 40.8 ± 1.7% of burrows were occupied or showed signs of occupation. Occupancy rates were low compared to those measured by systematic burrow inspection in other studies. Assuming that laying occurred in 80–93% of the estimated number of burrows, as estimated by previous studies, gives an estimate of 29 614 (95% CI: 19 388–45 235) to 34 426 (95% CI: 22 538–52 585) breeding pairs.

With a decline exceeding 30% over three generations, the once-common European Turtle-dove is now considered globally threatened by IUCN. As a legal game species in 10 European countries, the recent International Single Species Action Plan for this species highlighted the need to carry out an assessment of the sustainability of current levels of hunting. In 2013–2014, the Western European population was estimated at 1.3–2.1 million pairs, and the hunting bag in the same region to be 1.1 million birds. Using the Demographic Invariant Method, we assessed whether current levels of hunting harvest within Europe constitute overexploitation of the western flyway European Turtle-dove population. We calculated the maximum growth rate λmax that a population might achieve in the absence of any additive mortality. Then we estimated the potential maximum harvestable population fraction (P) allowed by excess population growth. We explored a wide range of plausible scenarios relating to assumed demographic rates, geographic scope of the flyway and management objectives. λmax was estimated to lie between 1.551 and 1.869. Current levels of hunting along the western flyway are more than double the sustainable fraction (P) under all suitably conservative scenarios, and only fall below this threshold under the most restrictive assumptions. We conclude that current levels of legal hunting along the western flyway are unlikely to be sustainable. Reducing uncertainty associated with assessments of the sustainability of turtle dove hunting will require improved information on (in order of decreasing importance) current levels of hunting, adult survival, age structure and population size.

An integrated research program was initiated to evaluate if the European shagPhalacrocorax aristotelis can be used as a robust indicator of themarine environment in Mor Braz, Brittany, France. This program focuses on aspects of theecology of the shag including its abundance, demography, diet and at-sea distributionmeasured at three breeding colonies. The annual population growth rate was estimated at1.01 for the period 1987–2009. The number of breeding pairs (mean: 565) was highlyvariable from year to year. Part of this interannual variation was explained by variationsin sea surface temperature and sea surface height in winter and spring: the number ofbreeding 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 distancesseparating these islets. Average productivity was one young fledged per nest, but itvaried between years and islets. Density of individuals at sea varied between 1.40ind.km-2 during the breeding season and 3.08 ind.km-2 after thebreeding season had ended. Individuals foraged up to 7 km from the nest and performed onaverage 2.7 foraging trips per day. The average number of dives deeper than 5 m variedfrom 126 to 400 per day. Mean diving depth, dive duration and time spent at bottom were 13m, 28 s, and 19 s respectively. Regurgitated pellets were collected regularly. Four fishfamilies (Gadidae, Gobiidae, Atherinidae and Labridae) represented more than 65% of thepreys throughout the year, a percentage reaching more than 95% of the prey from May toOctober. The other fish in the diet were Cottidae, Ammodytidae, and Clupeidae. The diet ofthe European shag consisted of benthic fish throughout the year, and also included pelagicfish more frequently between June and October. The synchronous variations of productivitybetween colonies suggest that some common environmental factors affect this demographicparameter at the regional scale. Thus, the European shag has a good potential for being areliable ecological indicator of the state of this marine environment. Finally, improvedknowledge on the foraging ecology of shags will be useful in the process of designingMarine Protected Areas in the Mor Braz to help ensure sustainable management of marineresources and biodiversity conservation.

The juvenile phase is poorly known in Antarctic seabirds, despite being a critical period for individual survival. To better understand the ecology of young Antarctic seabirds, we surveyed for the first time the three-dimensional habitat use of six juvenile emperor penguins during their post-natal dispersal from Terre Adélie, using bio-telemetric tags. The tags transmitted location and activity data for nearly 100 days on average. One individual was followed during eight months and covered 7000 km, which represents the longest continuous individual survey for the species. Studied individuals first dispersed away from Antarctica, up to 54.7°S and 1250 km north of the pack-ice edge, in the Polar Frontal Zone. This highlighted a much looser association with sea ice and a greater at-sea range compared to previous knowledge on breeding adults. Juvenile penguins then moved southwards close to the extending pack-ice during autumn and winter. Over the survey duration, juveniles showed a contrasting use of marine habitats, with less mobility, less time underwater, and shallower dives (generally not over 50–100 m) in the pack ice, versus greater distances travelled, more time spent underwater, especially deeper than 100 m (up to 250–300 m) in open water. We discuss hypotheses which could explain the northward exodus of juvenile emperor penguins across contrasting habitats.

The emperor penguin (Aptenodytes forsteri) is highly dependent on sea ice conditions, and future climate change may affect its distribution and numbers. Most studies on the demography and population dynamics of emperor penguins in relation to sea ice characteristics were conducted at a single colony (Pointe Géologie). Several non-exclusive hypotheses have been proposed to explain the dramatic decline of this colony, including changes in sea ice conditions, predation, flipper banding and human disturbance. Here, we report and analyse updated long-term trends in numbers of breeding pairs made at two colonies (Pointe Géologie and Haswell Island) where counts are comparable. Similar changes were observed for both colonies and paralleled changes in sea ice extent. At Pointe Géologie and Haswell Island, populations declined similarly and later growth rates were also similar since the early 1990s for Haswell and early 1980s for Pointe Géologie. The magnitude of the decline was similar between both colonies when numbers of breeding pairs were assessed. This study suggests that a common large-scale environmental factor has probably negatively affected both colonies.

In their recent review article “Paradigm lost, or is top-down forcing no longer significant in the Antarctic marine ecosystem?” Ainley et al. (2007) questioned why Southern Ocean marine ecologists apparently have shifted to a central paradigm where bottom-up forcing by physics and climate change has become the single most important driver of food web dynamics in the Southern Ocean. Ainley et al. (2007) suggest that top-down forcing (forcing by biotic processes) is no longer considered in the interpretation of ecological research results aimed at understanding ecosystem processes of the Southern Ocean. Based on two examples from the literature they suggest that population trends could better be explained by including species interactions in the modelling rather than by changes in climate related physical processes alone. Nicol et al. (2007) questioned the paradigm shift proposed by Ainley et al. (2007) and made a broad review of the ecological research conducted in the Southern Ocean ecosystems. They concluded that there has been considerable research effort into ecosystem interactions over the last 25 years in the Southern Ocean, and that there seems little evidence that there has been an almost complete shift in paradigms; rather both bottom-up and top-down processes are recognized to govern ecosystems functioning.

It has been suggested that the large grey seal colonies around the British Isles form local populations within a metapopulation, and that seal movements outside the breeding season lead to considerable overlap between individual home ranges. Individual behaviour and population dynamics of small peripheral colonies may also play a role in the metapopulation. We studied the French grey seal colony of the Molène archipelago, at the southern-most limit of the species' range. We analysed photo-identification data with capture–mark–recapture techniques in order to estimate the total seasonal abundance of grey seals in the archipelago and to quantify the seasonal rates of occurrence or movements of male and female seals. We found that between 58 (95% confidence interval: 48–71) and 98 (95% CI: 75–175) individuals hauled out in the archipelago during the summers of 1999 and 2000. The use of multistate models allowed the assessment of seasonal site fidelity and indicated that it varied between key periods of the annual cycle, particularly for females. Males showed a constant fidelity rate of 56% from one season to another. Hence, even though they showed high inter-annual site fidelity, they did not seem to have a preferred season for using the archipelago. On the contrary, female grey seals showed the highest site fidelity between moult and summer (around 80%), and the lowest fidelity between summer and the breeding period (34–43%). Thus, females seem to use the Molène archipelago preferentially in summer and leave the site before the breeding season, which explains the very low local pup production. Philopatry may explain this pre-breeding emigration, and we suggest that most grey seals observed in the Molène archipelago were born and breed in other local breeding populations, probably the south-western British Isles.

The blue petrel (Halobaena caerulea) is a small pelagic seabird breeding on just a few Southern Ocean islands. Although it is known that oceanographic and climatic variability affect mortality rates, individual body condition and reproductive success, very few data are available on the global population status. We assessed the status of blue petrels at Mayes Island, Iles Kerguelen, in 2002 by estimating burrow densities and burrow occupancy using acoustic playbacks and response probability. The mean and highest burrow densities recorded were respectively 0.136 ± 0.026 and 2.3 entrances per m2. Burrow occupancy increased with burrow density but stabilized at c. 0.6 occupied burrows per m2. Taking into account the response probability to playback (0.819) the mean burrow occupancy density was 0.037 ± 0.094 per m2, giving an estimated 142 000 (95% CI around 106 000–179 000) or 148 000 breeding pairs (95% CI around 55 000–241 000) on Mayes Island, respectively with and without taking into account spatial autocorrelation in burrow densities. This suggests that the entire breeding population of blue petrels at Kerguelen is much higher than current estimates, and that Kerguelen and Diego Ramírez archipelagos are key breeding sites for this species.

The red-crested pochard (Netta rufina), a Eurasian diving duck, has seen its numbers declining and has received strong conservation concern. Data on population size and rate of decline are required to establish management plans, none of which is available for this species. Here we present the first population size estimate taking into account detection probability and habitat use in the Camargue, southern France. A non-random sample of 33 lakes was used to estimate detection probability from point-counts. Detectability was low, with only 57.5% of individual broods detected. A random sample of 37 lakes was then used to estimate brood densities. Adjusted densities (taking into account detection probability) were 0.1106 broods per ha of reedbed. Adjusted densities were extrapolated to the entire surface area of reedbeds in the Camargue estimated from a GIS to obtain abundance estimates of the brood population. A minimum estimate of 559 breeding pairs was obtained (95% confidence interval: 436-855). This estimate is much higher than previous ones (80-100 pairs for the Camargue, 250 pairs for France), and indicates strong underestimation of the population size when not taking into account detectability. Our results suggest that the red-crested pochard may require a reassessment of its conservation status for France and Europe. They further suggest that taking detection probability into account in population estimates of other cryptic species, and notably those of conservation concern, may help clarify their conservation status and may even affect the setting of conservation priorities.

Although world oceans have been warming over the past 50 years, the impact on biotic components is poorly understood because of the difficulty of obtaining long-term datasets on marine organisms. The Southern Ocean plays a critical role in global climate and there is growing evidence of climate warming. We show that air temperatures measured by meteorological stations have steadily increased over the past 50 years in the southern Indian Ocean, the increase starting in mid 1960s and stabilizing in mid 1980s, being particularly important in the sub-Antarctic sector. At the same time, with a time lag of 2–9 years with temperatures, the population size of most seabirds and seals monitored on several breeding sites have decreased severely, whilst two species have increased at the same time. These changes, together with indications of a simultaneous decrease in secondary production in sub-Antarctic waters and the reduction of sea-ice extent further south, indicate that a major system shift has occurred in the Indian Ocean part of the Southern Ocean. This shift illustrates the high sensitivity of marine ecosystems, and especially upper trophic level predators, to climatic changes.

Reedbeds of the Rhône river delta, southern France, constitute an important breeding habitat for purple herons (Ardea purpurea) in Europe. However, the area of reed harvested commercially has increased in recent years and, since 1997, a European Union agri-environmental policy has been implemented to reconcile economic development with conservation goals for harvested reedbeds. Here, we investigate trends in breeding numbers of purple herons and the effect of reed harvesting on reedbed occupancy by herons. A regression model indicates that reedbed use by breeding herons was negatively affected by the reed harvesting pressure. An increase of nearly 50% in the harvested area following the implementation of the policy was probably caused by subsidies (from 67 to 100 US$/ha/year) proposed to reed harvesters, although associated with harvesting constraints intended to conserve heron colonies. The difference between the payments with and without colonies does not appear to have been sufficient to convince reed harvesters to conserve colonies. A case study showed that one heron colony located in a reserve area persisted, while another split into smaller colonies following modifications of reedbeds for future reed harvesting. Results suggest that the agri-environmental policy in its present form has failed to accomplish its primary objective of improving conditions for breeding purple herons in the Camargue. Potential breeding habitat for purple herons have decreased and urgent action is needed to protect some reedbeds from intense reed cutting.