Phoebetria Palpebrata Research Articles

Notodiscus (Charopidae) on South Georgia: some implications of shell size, shell shape, and site isolation in a singular sub-Antarctic land snail

AbstractMultivariate analysis shows that shells of Notodiscus sp. (Charopidae: Pulmonata) reported from South Georgia are smaller and proportionately taller than, but otherwise similar to, populations of Notodiscus hookeri (Reeve) from Iles Crozet and Iles Kerguelen. The origin of this solitary, and spatially limited, South Georgia population is enigmatic. It is confined to a remarkably small coastal lowland site which was glaciated at Last Glacial Maximum, precluding a Tertiary relict origin, and on the leeward north-east coast, ruling out post-glacial ocean rafting. The site is close to the King Edward Point settlement, yet the absence of any logistics connections with the Iles Crozet or Iles Kerguelen mitigates against anthropogenic introduction. The close proximity of the population to nests of blue-eyed shag (Phalacrocorax atriceps), Dominican gull (Larus dominicanus) and light-mantled sooty albatross (Phoebetria palpebrata) could imply the snail was originally introduced to South Georgia via these ocean transiting seabirds.

Morphological versus molecular identification of Sooty (Phoebetria fusca) and Light-mantled (P. palpebrata) albatross chicks

The two fuliginous albatross species, Phoebetria fusca (the Sooty albatross, SA) and P. palpebrata (the Light-mantled albatross, LMA), are found breeding close to each other on the Prince Edward Islands (Southern Ocean). Adults of these two species are easy to identify in the field, but the chicks are difficult to distinguish on the basis of external morphology, especially at very young ages. Many ecological studies involve sampling of chicks as well as adults, and accurate field identification of chicks is thus crucial. Traditionally, the extent of the ring of pale feathers around the eye (eye-ring) has been used to identify the fledglings. The aim of our study was to investigate the utility of characters associated with the eye-ring (extent, measured as an angle, and colour) for the identification of Phoebetria chicks. This was achieved by comparison of identifications based on morphology, with positive identifications based on DNA sequence data from the mitochondrial cytochrome b gene. We confirm the value of morphological criteria in distinguishing LMA and SA chicks, and this technique appears to be accurate in the majority of cases (>80%). However, we recommend using molecular identification for borderline cases (angle of the eye-ring measuring between 85 and 95°) if independent confirmation of chick identity cannot be obtained (e.g. via observed feeding interaction with an adult).

At-sea activity patterns of breeding and nonbreeding white-chinned petrels Procellaria aequinoctialis from South Georgia

Despite the recent burgeoning in predator tracking studies, few report on seabird activity patterns, despite the potential to provide important insights into foraging ecology and distribution. In the first year-round study for any small petrel, we examined the activity patterns of the white-chinned petrel Procellaria aequinoctialis based on data from combination geolocator-immersion loggers deployed on adults at South Georgia. The petrels were highly nocturnal, flying for greater proportions of darkness than any large procellarid studied so far, except the light-mantled albatross Phoebetria palpebrata. Flight bout durations were short compared with other species, suggesting a dominant foraging mode of small-scale searching within large prey patches. When migrating, birds reduced the proportion of time on the water and increased flight bout duration. Activity patterns changed seasonally: birds flew least during the nonbreeding period, and most frequently during chick-rearing in order to meet higher energy demands associated with provisioning offspring. The degree of their response to moonlight was also stage dependent (greatest in nonbreeding, and weakest in incubating birds), a trait potentially shared by other nocturnal petrels which will have repercussions for feeding success and prey selection. For the white-chinned petrel, which is commonly caught in longline fisheries, these results can be used to identify periods when birds are most susceptible to bycatch, and therefore when use of mitigation and checking for compliance is critical.

Free as a bird? Activity patterns of albatrosses during the nonbreeding period

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 406:291-303 (2010) - DOI: https://doi.org/10.3354/meps08532 Free as a bird? Activity patterns of albatrosses during the nonbreeding period Elizabeth K. Mackley1,2,*, Richard A. Phillips1, Janet R. D. Silk1, Ewan D. Wakefield1, Vsevolod Afanasyev1, James W. Fox1, Robert W. Furness2 1British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK 2Faculty of Biomedical and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK *Email: liz_mackley@glasgowalumni.net ABSTRACT: This is the first comprehensive study of at-sea activity patterns of albatrosses during the nonbreeding period, based on data from combination geolocator–immersion loggers deployed on the wandering albatross Diomedea exulans, black-browed albatross Thalassarche melanophris, grey-headed albatross T. chrysostoma and light-mantled albatross Phoebetria palpebrata from South Georgia (54°00’S, 38°03’W). Differences in behaviour among species observed during the breeding season were maintained during the nonbreeding period, suggesting a high degree of foraging niche specialisation. Wandering albatrosses exhibited longer flight bouts, and spent more time on the water during daylight, than any of the smaller species. Light-mantled albatrosses were the most active nocturnally. During daylight, grey-headed albatrosses were the most aerial and black-browed albatrosses had the shortest flight bouts. Although all species still engaged in foraging behaviour predominantly during daylight, they spent a greater proportion of time on the water (presumably resting) during the nonbreeding period compared with the breeding period, suggesting that they could more readily meet their energy demands when no longer subject to central place constraints. There was no evidence from activity patterns that might suggest that wing feather moult handicaps flight capability during the nonbreeding period. Individuals of all species engaged in rapid east–west commutes, when considerably higher proportions of time were spent in flight than while resident, in particular during daylight, possibly because birds are unable to navigate effectively during complete darkness. Despite consistency in individual dispersal patterns, there were year-to-year differences in the nocturnal behaviour of black-browed albatrosses, probably attributable to prey variability. KEY WORDS: Procellariiform · Seabird · Central place constraints · Commuting Full text in pdf format PreviousCite this article as: Mackley EK, Phillips RA, Silk JRD, Wakefield ED, Afanasyev V, Fox JW, Furness RW (2010) Free as a bird? Activity patterns of albatrosses during the nonbreeding period. Mar Ecol Prog Ser 406:291-303. https://doi.org/10.3354/meps08532 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 406. Online publication date: May 10, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Use of stable isotopes to quantify seasonal changes of trophic niche and levels of population and individual specialisation in seabirds

Niche variation is a widespread phenomenon that has important implications for ecolog- ical interactions and conservation biology, but few studies have quantified the trophic niche width (TNW) and its within- and between-individual components. We used stable isotopes of body feathers to investigate (1) seasonal isotopic niche changes of 4 southern procellariiforms and, (2) the level to which individuals are specialised relative to their population within each season. (1) δ 13 C and δ 15 N values of chicks and adults indicated a well-defined trophic segregation within the seabird assem- blage during both the breeding and poorly known moulting (inter-nesting) periods, and they under- lined marked species-specific seasonal changes. One species (light-mantled sooty albatross) remained within the Southern Ocean both during breeding and body feather moult, while the 3 others migrated either to oceanic subtropical waters (wandering and sooty albatrosses) or high isotopic marine areas (e.g. productive neritic waters; white-chinned petrel) during the moulting period. (2) Isotopic vari- ances and TNW were generally low, indicating that birds belong to isotopic specialist populations within a given period. Variances and TNW were larger for white-chinned petrel chicks and light-man- tled sooty albatross adults, respectively, indicating isotopic generalist populations and revealing 2 new foraging behaviours. Individual white-chinned petrel chicks segregated by their feather iso- topic signatures, thus indicating individual/pair specialisation of parent birds during the chick-rearing period. The light-mantled sooty albatross population included mostly isotopic generalist individuals during the moulting period, with individuals using different habitats and diets. The study highlights the utility of feather isotopic signature for determining TNW and points out the necessity to develop such new approaches to better depict niche variations at both population and individual levels.

Recent population estimates and trends in numbers of albatrosses and giant petrels breeding at the sub-Antarctic Prince Edward Islands

The second mid-summer survey of surface-nesting seabirds at the Prince Edward Island group (Marion and Prince Edward islands) was conducted during December 2008, seven years after the initial mid-summer survey. Wandering albatrosses Diomedea exulans may have decreased slightly at Prince Edward Island, mirroring a decrease of roughly 2% per year at Marion Island from 1998 to 2005, a decline that has since reversed. Numbers of grey-headed albatrosses Thalassarche chrysostoma on Marion Island have remained stable, whereas the population on Prince Edward Island decreased by 20% from 2001 to 2008 (3% per year). The estimate of Indian yellow-nosed albatrosses T. carteri at Prince Edward Island was similar in 2001 and 2008. Counts of both sooty albatrosses Phoebetria spp. were substantially higher at Prince Edward Island in 2008, possibly as a result of better coverage compared to 2001. Dark-mantled sooty albatrosses P. fusca on Marion Island have decreased by almost 2% per year since 1996, continuing a negative trend from the early 1980s, whereas light-mantled sooty albatrosses P. palpebrata have increased by almost 6% per year at Marion Island since 1996. Counts of both giant petrels increased at Prince Edward Island (northern Macronectes halli by 44%; southern M. giganteus by 28%), whereas their numbers have remained stable at Marion Island. Current best estimates for annual breeding populations (pairs) at the two islands are 3 650 wandering albatrosses, 9 500 grey-headed albatrosses, 7 000 Indian yellow-nosed albatrosses, 2 900 dark-mantled sooty albatrosses, 800 light-mantled sooty albatrosses, 750 northern giant petrels and 2 800 southern giant petrels, confirming the global importance of the Prince Edward Islands for these seven species. Apart from the dark-mantled sooty albatross, their populations are reasonably healthy despite fishing mortality.

Albatross foraging behaviour: no evidence for dual foraging, and limited support for anticipatory regulation of provisioning at South Georgia

Many pelagic seabirds are thought to regulate reproductive effort by adopting a dual foraging strategy, alternating or mixing short foraging trips over local shelf waters (maximising provi- sioning rates) with longer trips over distant oceanic water (allowing restoration of lost condition). Many species also respond to chick condition, decreasing food supply to over-fed, and sometimes increasing it to under-fed chicks. Analysis of tracking data from 4 albatross species breeding at South Georgia provided evidence that adults responded to prevailing environmental conditions, but did not provide evidence for a dual foraging strategy. Trip durations and maximum foraging ranges tended to follow a positively skewed, unimodal distribution, with the exception of the light-mantled albatross for which no significant modes were apparent. Individual distributions deviated from this, but none were strongly bimodal or showed regular alternation of trip lengths, trip distance or predominant bathy- metric regime. There were significant relationships between meal mass and trip duration, time since the last feed and chick condition on return, reflecting responses to current rather than predicted chick needs. On average, adults returned with smaller meals after 1 to 2 d trips, but otherwise stayed away until a threshold payload was obtained; consequently, provisioning rate (g d -1 ) was much greater after shorter trips. Lack of dual foraging may reflect the diversity of foraging zones available in this highly productive region. By inference, this would mean that adoption of dual foraging elsewhere is a con- sequence of greater heterogeneity in resource availability in waters surrounding those colonies.

First breeding record of the light-mantled sooty albatross (Phoebetria palpebrata) for the maritime Antarctic

The light-mantled sooty albatross is a medium-sized albatross with a circumpolar distribution in the Southern Ocean. The known breeding sites are restricted to Islands in sub-Antarctic latitudes close to the Antarctic convergence between 46° and 53°S. In the austral summer season 2008/2009 we discovered a new breeding colony with at least two confirmed and three probable nests at Fildes Peninsula, King George Island, South Shetland Islands, Antarctica (62°12′S, 59°01′W). The new breeding colony of light-mantled sooty albatross described here represents the southernmost breeding place of any albatross species ever recorded.

Population trends in a community of large Procellariiforms of Indian Ocean: Potential effects of environment and fisheries interactions

Despite the worrying conservation status of several albatross and petrel population, the long-term trends of many populations remain largely unknown and the causes of decline in many cases are known or very strongly suspected to be incidental mortality in fisheries. Here we combine long-term monitoring of population trends, breeding success and band recoveries to examine the past and current status of five species of albatrosses and giant petrels breeding at the same site: sooty albatross ( Phoebetria fusca), light-mantled albatross ( Phoebetria palpebrata), wandering albatross ( Diomedea exulans), northern giant ( Macronectes halli) and southern giant petrels ( Macronectes giganteus) on Possession Island, Crozet archipelago. We identified three groups of trends over a 25-years period (1980–2005) suggesting common underlying causes for these species in relation to their bioclimatic foraging ranges. The Antarctic species – light-mantled albatross and southern giant petrel – appeared stable and increased recently, the Sub-Antarctic species – wandering albatross and northern giant petrel – declined with intermediate periods of increase, and finally the subtropical species – sooty albatross – declined all over the period. Breeding success, indicative of environmental conditions, showed two kinds of pattern (low and fluctuating versus high and/or increasing) which were consistent with oceanographic variations as found in a previous study. We present the analysis of fisheries-related recoveries, indicative of fisheries bycatch risks showing specific catch rates. No direct relationship between population trends and longline fishing effort was detected, probably because census data alone are not sufficient to capture the potentially complex response of demographic parameters of different life stages to environmental variation. This study highlights the contrasted changes of procellariiform species and the particularly worrying status of the subtropical sooty albatrosses, and in a lesser extent of Sub-Antarctic species.

Preferred foraging areas of Heard Island albatrosses during chick raising and implications for the management of incidental mortality in fisheries

Abstract Incidental mortality in fisheries is causing declines in many albatross populations around the world. To assess potential interactions with regional fisheries satellite tags were used to track black‐browed albatrosses (Thalassarche melanophrys) and light‐mantled sooty albatrosses (Phoebetria palpebrata) breeding on Heard Island during the chick‐rearing periods of 2003/04. This was the first time individuals from either population had been tracked. Black‐browed albatrosses foraged largely within the Heard and McDonald Islands Economic Exclusion Zone (EEZ) north‐east of the island, although 20% of foraging trips were to areas north of the EEZ into Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.5.1 and 58.5.2 and into the Îles Kerguelen EEZ. In contrast, the light‐mantled sooty albatrosses foraged well south of Heard Island along the southern boundary of the Antarctic Circumpolar Current. Both species appear to face minimal risk of incidental mortality during the chick‐rearing period in the regulated, legal fisheries, but are threatened by illegal, unreported and unregulated (IUU) fishing vessels operating in the southern Indian Ocean. Copyright © 2007 John Wiley & Sons, Ltd.

Foraging behaviour of four albatross species by night and day

We integrated information from satellite transmitters, GPS loggers and wet/dry activity loggers to compare the at-sea behaviour of 4 sympatric albatross species by night and day: wander- ing Diomedea exulans, grey-headed Thalassarche chrysostoma, black-browed T. melanophrys and light-mantled sooty Phoebetria palpebrata (in total, 350 foraging trips by 101 individuals). Trip dura- tion, distance and maximum range varied more within species between stages (incubation, brood- guard and post-brood) than between species at the same stage, implying that reproductive con- straints are more important than interspecific competition in shaping foraging behaviour. Wandering albatrosses spent more time on the water in fewer, longer bouts than other species. The proportion of time spent on the water was similar among the 3 smaller species. The partitioning of foraging activ- ity between day and night varied little between species: all landed and took off more often, but spent less time overall on the water during the day than at night. This supports observations that alba- trosses forage most actively during daylight, even though many of their fish and squid prey approach the surface only at night. Albatrosses were more active on bright moonlit nights, seem to have no fixed daily requirement for sleep, rest or digestion time on the water, can navigate in darkness, and are probably unhindered by the slight reduction in mean wind strength at night. They are probably less active at night because their ability to see and capture prey from the air is reduced and it is then more energy-efficient for them to rest or to catch prey using a 'sit-and-wait' foraging strategy.

Provisioning strategies and growth patterns of Light-mantled Sooty Albatrosses Phoebetria palpebrata on Macquarie Island

Provisioning regimes and growth of Light-mantled Sooty Albatrosses (LMSA) (Phoebetria palpebrata) were investigated on subantarctic Macquarie Island using an automatic tracking system and automatic weighing nests. The nests were deployed under five chicks in the post-brood provisioning period in 2000 and 2001. Adults typically utilised a cyclical foraging strategy consisting of a long foraging trip followed by three to four shorter trips. Chicks received an average (±SE) of 37.5±2.3 kg of food in the post-brood provisioning period and were fed every 1.6±0.1 days with a mean meal size of 520±10 g. Chicks grew at a rate of 61.3±1.0 g day-1 to a peak mass of 4.4±0.1 kg. Mean chick fledging mass was 3.0±0.1 kg. LMSA on Macquarie Island fed their chicks more frequently and showed a lower mean trip duration than conspecifics at South Georgia, which is likely related to proximity of productive Antarctic shelf waters, differences in prey availability and competition with other Procellariiformes.

Foraging and provisioning strategies of the light-mantled sooty albatross at South Georgia: competition and co-existence with sympatric pelagic predators

Foraging and provisioning strategies of the light-mantled sooty albatross (LMSA) Phoebetria palpebrata were studied during chick-rearing at Bird Island, South Georgia, in January to May 2003. Virtually all trips of satellite-tracked birds were restricted to Antarctic waters. Individual birds followed a diversity of foraging routes, the majority to shelf and shelf-slope areas along the southern Scotia Arc or to oceanic waters in the mid Scotia Sea, with only a few trips extending as far south as the marginal ice zone in the Weddell Sea. Sympatric white-chinned petrels Procellaria aequinoctialis, black-browed Thalassarche melanophrys and grey-headed albatrosses T. chrysostoma also exploit these areas. Unlike LMSA, these species and the wandering albatross Diomedea exulans, also forage on the shelf and shelf-slope waters surrounding South Georgia, or at the Antarctic Polar Front (APF), where the larger albatrosses and smaller, more manoeuvrable white-chinned petrel may out-compete LMSA for access to prey. As a consequence, foraging distances and maximum ranges are greater, chick-feeding frequencies are lower and chick growth rate is slower in LMSA than in sympatric Thalassarche albatrosses, and adult LMSA appear to have little capacity to regulate provisioning according to chick condition. Nonetheless, LMSA seem well-adapted to exploitation of distant foraging grounds, apparently using the wind to reduce flight costs and, in comparison with other albatrosses, spending more of the night on the wing and returning with food loads that represent a greater proportion of adult mass.

Chick metabolic rate and growth in three species of albatross: a comparative study

The relative importance of genetic vs. environmental factors in determining the pattern of avian post-embryonic development is much debated. Previous cross-fostering of albatrosses suggested that although inter-specific variation in growth rate was determined primarily by differences in dietary energy content, species-specific constraints might have evolved that could limit maximal growth, even in chicks fed at similar rates and on similar diets. This study aimed to determine whether intrinsic differences in resting metabolic rate were apparent during the linear phase of growth in chicks of three species (black-browed, grey-headed and light-mantled sooty albatrosses). There was a gradual increase in absolute, and a reduction in mass-specific metabolic rate from 5.0 W kg −1 during the earliest part of linear growth, to 3.5 W kg −1 by the time chicks reached peak mass. These values are considerably higher than in resting adults of comparable or lower mass, presumably reflecting the large size and high metabolic demand of organs involved in rapid nutrient processing and tissue synthesis by chicks. The lack of any detectable inter-specific variation in the pattern of metabolic rate changes casts some doubt on the existence of fundamental differences in growth rate that cannot be attributed simply to differences in dietary energy or nutrient delivery rate.

The influence of synoptic weather patterns on the at-sea behaviour of three species of albatross

The relationships between behaviour and synoptic-scale weather patterns and wind speeds for wandering (Diomedea exulans), black-browed (D. melanophrys) and light-mantled sooty (Phoebetria palpebrata) albatrosses were examined using observations collected from ships in the Southern Ocean south of Tasmania, Australia. Wandering albatrosses were found in high-pressure systems in significantly higher numbers than expected than in low-pressure systems. Wandering albatrosses were also found more frequently at lower latitudes than were black-browed and light-mantled sooty albatrosses. Light-mantled sooty and black-browed albatrosses showed no significant association with high- or low-pressure systems, suggesting that they can use either pressure system for travel. High-pressure systems may act as "traps" for wandering albatrosses, due to the lower wind speeds generally associated with these systems.

Kleptoparasitism by Brown Skuas on Albatrosses and Giant-Petrels in the Indian Ocean

The behavior of skuas and jaegers (subfamily Stercorarinae) when kleptoparasitizing other seabirds has been studied in detail at breeding colonies (Furness 1987a, b; Maxson and Bernstein 1982; Le Corre and Jouventin 1997), at a coastal estuary along a migration route in Britain (Taylor 1979), in boundary currents off Peru and south Africa (Duffy 1982), and in pelagic waters of the Eastern Tropical Pacific (Spear and Ainley 1993). The size of the host is usually smaller than that of the kleptoparasite. Indeed, only 9 of the 40 host species recorded had a mean body mass greater than that of the parasite (mean body mass of the host was 1.1 to 2.4 times greater than that of the kleptoparasite; Table 1). Attacks by skuas on giant-petrels and albatrosses have not been described. Therefore, we were surprised to see attempted kleptoparasitism by Brown Skuas (form from the Crozet and Kerguelen archipelagoes = Catharacta antarctica lonnbergi sensu Devillers 1978, Malling-Olsen and Larsson 1997; but see Peter et al. 1994) on a Wandering Albatross (Diomedea exulans) and a Northern Giant-Petrel (Macronectes halli), because these hosts are 5.9 and 2.6 times larger, respectively, than the skuas (Table 1). We also report an attempted kleptoparasitism by a Brown Skua on a Light-mantled Albatross (Phoebetria palpebrata) in the Kerguelen Archipelago, and four attempts by Brown Skuas (the Amsterdam Island [Indian Ocean] form, which is similar in size to the Tristan Brown Skua [C. a. hamiltoni]) on Yellow-nosed Albatrosses (Thalassarche chlororhynchos bassi) adjacent to the primary breeding colony of the latter at Amsterdam Island. The kleptoparasitism attempts on the Wandering Albatross and Northern Giant-Petrel were observed while we surveyed seabirds from the R / V Marion Dufrense in the southwestern Indian Ocean. The incident involving the albatross happened on 9 November 1997 at 44?09'S, 51?26'E (238 km from the Crozet Islands), and that involving the giant-petrel occurred on 14 November 1997 at 49?21'S, 66?43'E (147 km from the Kerguelen Islands). LBS, CSO, and SNGH saw both attempts from the flying bridge; DL saw the first attempt from the bridge. The Brown Skua that attacked the albatross was in

Satellite Tracking of Southern Buller's Albatrosses from the Snares, New Zealand

Pelagic seabirds spend most of their time foraging at sea far from their breeding grounds. Yet most information on their ecology comes from land-based studies, and the need for studies on their foraging ecology has been recognised as of prime importance to an understanding of their extreme life history traits (Ricklefs 1990). Recently, such studies have been made possible for large seabirds such as albatrosses with the development of satellite telemetry (Jouventin and Weimerskirch 1990). However, most studies have concentrated on the largest of the albatross species (e.g., Prince et al. 1992, Weimerskirch et al. 1993, Nicholls et al. 1994), with only one on a smaller species, the Lightmantled Sooty Albatross Phoebetria palpebrata (Weimerskirch and Robertson 1994). No studies have been published on mollymawks, the subfamily with the greatest number of species. Buller's Albatrosses (Diomedea bulleri) are endemic to New Zealand, where the Southern subspecies (D. b. bulleri) breeds at The Snares and the Solander Islands, and the Northern subspecies (D. b. platei) at the Chatham and Three Kings Islands (Turbott 1990). Their distribution at sea is poorly known, although the pelagic range is across the Southern Pacific Ocean, north of the Antarctic Convergence from southeastern Australia to Chile and Peru (Marchant and Higgins 1990). Movements of adults are also poorly known, and Marchant and Higgins (1990) suggested that they may move only locally. An examination of 27 regurgitations from adults and chicks collected on The Snares and the Chatham Islands (West and Imber 1986) indicated that the diet comprised mainly species which occur within the New Zealand region. However, Richdale (1949) showed that incubation spans of birds on The Snares ranged up to 21 days, indicating that these birds could forage long distances form the breeding colonies. Substantial mortality of Southern Buller's Albatrosses has been reported to occur as a result of commercial fisheries southwest of New Zealand (Bartle 1991, Murray et al. 1993), so knowledge of the foraging zones of the subspecies has important implications for conservation. We used satellite telemetry to determine the foraging movements during late incubation of Southern Buller's Albatrosses breeding at The Snares.

The diets and dietary segregation of sooty albatrosses (Phoebetria spp.) at subantarctic Marion Island

Subantarctic Marion Island is one of the few localities where the congeneric albatrosses Phoebetria fusca and P. palpebrata breed sympatrically. Chicks of both species at Marion Island were induced to regurgitate their stomach contents after being fed. Liquid formed over half the diet by mass. Cephalopods occurred most frequently in both species' diets. In terms of mass, cephalopods formed the larger part of the diet of sooty albatrosses, whereas fish was more important to light-mantled sooty albatrosses. Crustaceans and birds were also recorded for both species. Squid of the families Onychoteuthidae, Histioteuthidae, Chiroteuthidae and Cranchiidae occurred most abundantly in both species. Most squid taken by both albatrosses were of species known to float after death, suggesting that scavenging plays an important role in the species' foraging behaviour. Light-mantled sooty albatrosses consumed more squid restricted to the south of the Antarctic Polar Front than did sooty albatrosses, supporting a trend to latitudinal segregation of the two species while foraging.

Dead or alive, night or day: how do albatrosses catch squid?

For many albatross species squid are important prey. Whether albatrosses depend on scavenging (e.g. of vomit from cetaceans, post-spawning die-offs or fishery waste) or on live-capture of squid (e.g. via diel vertical migrations in association with aggregations of squid prey) is controversial. This review of the nature of interactions between squid and the four species of albatross breeding at South Georgia uses data on the foraging range, methods and timing of feeding of the albatrosses in relation to the size, distribution, buoyancy characteristics (floaters or sinkers), bioluminescence and prey of the squid and access to fishery waste. We conclude that most evidence for scavenging needs critical re-evaluation; nevertheless, whereas wandering albatrosses and possibly light-mantled sooty albatrosses probably depend significantly on scavenged squid, black-browed and especially grey-headed albatrosses are unlikely to do so.

Satellite tracking of light-mantled sooty albatrosses

Five light-mantled sooty albatrosses (Phoebetria palpebrata) breeding at Macquarie Island were tracked with miniaturised satellite transmitters during foraging trips of the incubation period. Birds moved rapidly to specific sectors of the Southern Ocean, where they spent several days foraging before returning to their nests. These specific sectors were at an average distance of 1516 km from Macquarie Island and located in pelagic Antarctic waters, mostly along the Antarctic continent. The maximum foraging range was in average 1721 km and the total distance covered by two birds for which there were complete tracks was 6463 and 6975 km. This study confirms previous suggestions that light-mantled sooty albatrosses are able to forage in the waters of the high Antarctic while breeding in the sub-Antarctic. The implications of the extreme separation of feeding zones from nesting grounds, in terms of conservation and life-history strategies, are discussed.