Population dynamics of Black-browed and Grey-headed Albatrosses Diomedea melanophrys and D. chrysostoma at Campbell Island, New Zealand, 1942–96

The numbers of Black-browed Albatrosses Diomedea melanophrys and Grey-headed Albatrosses D. chrysostoma at Campbell Island, New Zealand, have declined dramatically since the 1940s. Black-browed Albatross numbers went into a steep decline in the 1970s and, since at least 1984, have been increasing slightly at average rates of 1.1% and 2.1% per annum at two colonies. The long-term downward trend in numbers of the Grey-headed Albatross has continued into the 1990s, averaging annually between 3.0% and 4.8% per annum at different colonies. A demographic study carried out between 1984 and 1996 indicates that Black-browed and Grey-headed Albatrosses have similarly high annual adult survival rates (0.945 and 0.953, respectively). Black-browed Albatrosses breed for the first time at a younger average age than do Grey-headed Albatrosses (10 years and 13.5 years, respectively), have a higher average breeding success (0.663 compared with 0.397 for the latter species) and are annual breeders whereas Greyheaded Albatross show a typical biennial pattern of breeding. Both show low survival from fledging to first breeding; averaging 0.186 and 0.162 for Black-browed and Grey-headed Albatrosses, respectively. Both species are accidentally killed in the Japanese long-line fishery for tuna Thunnus sp. in the Australasian region. The steep decline of Black-browed Albatross numbers in the 1970s was concomitant with the development of this fishery in the foraging region of the Campbell Island birds. Currently, the slight increase in numbers is due to high adult survival rates and breeding success, and is coincident with a great reduction in long-line fishing. With stable and high adult survival rates, it is expected that future population trends will be mainly influenced by the recruitment rates. The continuous decline in Grey-headed Albatross numbers since the 1940s, before long-line fishing developed in this region, indicates that natural environmental processes contributed to the downward trend in breeding numbers. Modelling indicates that Grey-headed Albatross numbers will continue to decrease with the present demographic parameters. A comparison between the species breeding at different sites shows that differing environmental conditions influence demographic characteristics.     

Breeding frequency in Grey-headed Albatrosses Thalassarche chrysostoma

Although Grey-headed Albatrosses Thalassarche chrysostoma are usually regarded as biennial breeders, taking a year off following a successful breeding attempt, a small proportion of successful birds attempt to breed annually. This proportion was higher at Marion Island (5.4%) than at Bird Island, South Georgia (1.0%), suggesting that conditions are more favourable at Marion Island. This hypothesis is supported by higher average breeding success and shorter lags following both successful and failed breeding attempts at Marion Island. Factors favouring reproduction at Marion Island may include reduced intraspecific competition (given the much smaller breeding population) and/or more predictable food supply (owing to production of meso-scale eddies associated with the Indian Ocean Ridge). Although annual breeding appeared to increase the risk of adult mortality, with several birds that attempted to breed annually found dead the following year, at least some birds greatly enhanced their reproductive output, with one male raising five chicks in five successive years. Contrary to life-history theory, there was no evidence that older birds were more likely to attempt annual breeding because of declining reproductive value.     

Moult in Black-browed and Grey-headed Albatrosses Diomedea melanophris and D. chrysostoma

We recorded the age of individual wing and tail feathers of Black-browed and Grey-headed Albatrosses Diomedea melanophris and D. chrysostoma of known age and breeding status at Bird Island, South Georgia. Breeders and non-breeders of both species moult their rectrices annually. Non-breeders moult primaries biennially. In the first year of a cycle, the outer three and some inner primaries are moulted descendantly; in the next year the inner primaries are moulted ascendantly, starting from primary seven. There is a general progression to moulting equal numbers of primaries in each half of the cycle by the time breeding starts at about 10 years of age. Grey-headed Albatrosses usually moult fewer primaries than Black-browed Albatrosses, particularly as 3-year-olds, when they undertake substantial plumage change in body moult. Most secondaries in Black-browed Albatrosses have been replaced once by age 4 years. Breeding Black-browed Albatrosses continue the moult pattern established as immatures whether they fail or not, as do failed Grey-headed Albatrosses. Successful Grey-headed Albatrosses, which breed again 16 months later, moult their three innermost primaries after breeding in the remainder of the current year and, after a period when moult is interrupted, renew the remaining primaries the following year. Comparisons between species and between failed and successful birds within species indicate that moult rate is not closely linked to the length of the interval between breeding attempts. Interspecies differences are better explained by breeding latitude, with tropical albatrosses moulting twice as fast as sub-Antarctic species, possibly reflecting food availability outside the breeding season.     

THE FOOD AND FEEDING ECOLOGY OF GREY-HEADED ALBATROSS DIOMEDEA CHRYSOSTOMA AND BLACK-BROWED ALBATROSS D. MELANOPHRIS

The food and feeding ecology of Black-browed Albatrosses and Grey-headed Albatrosses was studied from 1975 to 1978 at Bird Island, South Georgia. Two hundred and seventy food samples (averaging 75–85 % by weight of the mean chick feed) were collected from adults of each species in February and March. Chicks of both species received meals of the same size, of which half consisted of liquid. The three major components of the solid diet (krill, squid and fish) were similar for both albatrosses. By weight, fish represented about 35 % of the diet of both species; squid predominated (50 %) in the diet of Grey-headed Albatross, and krill (40 %) in the diet of Black-browed Albatross. Lampreys were confined to the Grey-headed Albatross and, although squid of similar sizes were taken by both species, Black-browed Albatrosses took a much greater diversity of squid. Each major prey type was associated with a characteristic amount of liquid in the complete samples and only in the case of krill and lamprey was this lipid-rich.
As these two albatrosses are of similar size, breed over the same period and feed meals of equivalent weight to their chicks at similar intervals, the difference in the composition of the diet is possibly the most significant mechanism of ecological segregation (in the breeding season).
Evidence of the effect of krill shortage in drastically reducing Black-browed Albatross breeding success is presented to support this. The two species have largely non-overlapping winter oceanic ranges which are probably also correlated with the distribution of preferred prey.     

Chick provisioning rates and growth in Blacklbrowed Albatross Diomedea melanophris and Grey-headed Albatross D. chrysostoma at Bird Island, South Georgia

We compared the parental division of labour and the pattern and rate of parental provisioning by two sympatric species of albatross of similar mass and breeding timetable but differing in diet and in the duration of chick‐rearing. Using electronic weighing platforms inside artificial nests, we recorded chick mass of Black‐browed Albatross and Grey‐headed Albatross at Bird Island, South Georgia every 10 minutes for both species in 1993 and 1994 and for each species in two other years between 1990 and 1996. The chick mass data (nearly one million weighings) were used to calculate meal mass (over 5000 meals) and intervals between meals. Adult birds were fitted with radio‐transmitters which allowed each meal to be allocated to the appropriate parent. The combination of meal mass and foraging trip duration were used to calculate provisioning rates for chicks and individual adults. Overall, Black‐browed Albatrosses delivered significantly lighter meals (569 g) than Grey‐headed Albatrosses (616 g) but more frequently (every 2.07 days and 2.50 days respectively). Thus combining foraging trip data for both parents, Black‐browed Albatross chicks received a meal every 1.22 days compared with 1.26 days for Greyheaded Albatross. These rates did not differ significantly. The contribution of each sex of each species in chick provisioning fluctuated between years, being similar in some years or biased towards males in others. Chicks of both species that failed to fledge received smaller, less frequent meals than successful chicks. In 1990 and 1994, Black‐browed Albatross chick provisioning rates were lower than in 1992 and 1993. In 1990, both meal mass and trip duration were affected, but only in 1994 was trip duration longer. Greyheaded Albatross chick provisioning rate was lower in 1994 than in other years but trip duration was longer. In each species, significant changes in meal mass and trip duration occurred within the chick‐rearing period. Chick provisioning rates invariably declined before chicks attained their peak mass. For both species, chick growth rates and peak and fledging mass, but not fledging age, were affected by differences in provisioning rate.     

Sooty shearwater (

Rakiura Maori annually harvest sooty shearwater (Puffinus griseus) chicks from islands in Foveaux Strait and adjacent to Stewart Island, New Zealand. Chick availability and the number of chicks harvested were estimated during the 1994 and 1995 seasons on Poutama (Evening Island). Burrow entrance densities estimated using circular plots were significantly higher in 1994 (0.45 ± 0.03 per m) than in 1995 (0.41 ± 0.03 per m). A similar burrow entrance density (0.45 ± 0.04 per m) was obtained in 1995 using a transect sampling technique. The number of usable burrows estimated using circular plots in 1994 and 1995 was 387 508 and 337 732 respectively. Of these, chicks occupied 24% ± 6% in 1994 and 29% ± 4% in 1995. It was estimated the muttonbirders harvested 13-24% (15 722) of the chicks present on Poutama in 1994 and 17-28% (22 092) in 1995. Muttonbirders targeted areas of the island with higher chick density and less fallen stems. Excluding chicks rejected by the muttonbirder (less than or equal to 750g), harvested chicks were significantly heavier and had less down than randomly encountered chicks. If larger heavier chicks are more likely to return and breed, then the preference for these chicks by muttonbirders would affect predictions of harvest impacts.     

Effects of age, cohort and individual on breeding performance in the Lapwing Vanellus vanellus

The breeding performance of individually colour-ringed Lapwings Vanellus vanellus was studied on marginal grassland in Upper Teesdale, County Durham (UK), from 1992 to 1995. Contrary to many studies of birds, female age had only a minor effect on breeding performance: yearling females produced eggs on average 5% smaller than those of adults. In contrast, the average productivity of male Lapwings was estimated to increase by around 40% between one and two years of age, and by a further 10% between two and three years of age. This was because of a 40% increase in the proportion of males that bred between one and two years of age, and of an increase in mating success with age coupled with a higher breeding success for polygynous males. The likelihood of breeding for male Lapwings was affected by year of hatching. More than half of those males that hatched in 1990, and which were present in both 1993 and 1994, did not breed. It was suggested that this was due to environmental effects experienced by these males as chicks, resulting in reduced success in securing a breeding territory later in life. Individual female Lapwings showed a high degree of consistency between years in both laying date and egg size, and those that raised up to two young in 1993 raised approximately the same number in 1994. However, females producing more than two young in 1993 raised significantly fewer in 1994, perhaps suggesting a cost of reproduction.     

The breeding biology and factors affecting reproductive success in rockhopper penguins <Emphasis Type="Italic">Eudyptes chrysocome</Emphasis> at Macquarie Island

Adult mass changes, egg morphometrics, chick growth rates, fledging masses, reproductive success and reasons for reproductive failure were examined in rockhopper penguins at Macquarie Island from 1993/1994 to 1995/1996. Mean arrival masses, growth rates of chicks and fledging masses exhibited inter-annual variability, while egg morphometrics, hatching success (68.0±6.0%) and reproductive success (47.3±8.3%) were constant between years. Reproductive failures occurred primarily during incubation, with the majority of eggs lost to great skuas. Logistic regressions revealed that no variable significantly explained hatching success, and only in 1994/1995 was fledging success significantly correlated with the position of nest in the colony (those in the centre were more successful than those on the periphery). Reproductive success during this study was relatively high, and therefore an assessment during poor years would be instructive, particularly in relation to aspects of the penguins’ foraging ecology.     

Influence of adult breeding experience on growth and provisioning of Wandering Albatross Diomedea exulans chicks at South Georgia

For most seabirds, reproductive performance improves with age; in albatrosses this is thought not to be so (experience being acquired before starting breeding) but only one study (of chick growth in a single season at one site) has specifically addressed this. We compared the provisioning performance and growth rates of chicks of Wandering Albatrosses Diomedea exulans breeding for the first (IN), second and third (LE) and fourth or more times (EE) on Bird Island, South Georgia in the austral winters of 1996 and 1997. Eggs from EE adults were significantly heavier than the other two categories and these chicks had a greater mass and longer wings up to 160 days of age and longer culmen and tarsus up to 115 days old. However chicks from all categories fledged at the same average mass, size and age. No significant differences between categories in feeding frequency or meal size were detected but experienced adults made shorter long foraging trips and spent more time at the nest than less experienced birds. Adults that remained at the nest gave chicks smaller meals than those that left immediately after feeding the chick. Although provision of smaller but more frequent meals by experienced adults promotes more rapid chick growth, the resulting differences do not persist into the late chick-rearing period. Our results were very similar to those from Iles Crozet in the Indian Ocean, supporting the hypothesis that when Wandering Albatrosses start to breed they are fully competent foragers but that it takes a while, during early chick-rearing, for birds breeding for the first time to adapt to the additional demands of provisioning a chick.     

The effect of maternal age and experience on egg-size and hatching success in Wandering Albatrosses Diomedea exulans

The roles of maternal age and experience, on the one hand, and individual, year and random effects on the other, in influencing avian egg-size and hatching success have been much debated but seldom studied comprehensively. We investigated these topics with Wandering Albatrosses Diomedea exulans of known age (7–30 years) and experience (1–8 breeding attempts) over a 10-year period. Older and more experienced birds laid larger eggs. After allowing for year and controlling for experience, significant age effects remained; after controlling for age, no detectable experience effects remained. However, age accounted for only 6% of the overall egg-size variation. Egg-size varied significantly between years and has increased over the last decade. Individuals laid eggs of consistent sizes; 55% of the random variation in egg-weight was due to such effects. Egg- and hatchling-weight were very closely linked; larger eggs also had higher hatching success. The latter was influenced significantly by age and experience but neither remained significant after controlling for the other. Year effects were also detectable.
That there are significant effects of age, experience, year and individual on egg-weight (and hatching success) is probably typical of seabirds generally, though with different balances between factors depending on species and situation; however, insufficient data exist to examine this critically. Our finding that age was a more important influence than breeding experience does not support recent suggestions that hatching success is mainly influenced by experience and that experience will have a greater effect on reproductive success in long-lived species with high mate-fidelity. However, Wandering Albatrosses may have acquired much relevant experience before even starting to breed.     

A winter's tale: Among-year variation in bird community structure in a southeastern Australian forest

Abstract The bird community structure of an undisturbed forest (Olinda State Forest) east of Melbourne, Victoria, varied greatly among the winters of 1993, 1994 and 1995. Increases in the total density of all diurnally active species were as much as 66% between winters [381 versus 633 birds per 50 ha (the density unit used throughout)]. Community structure differed significantly among all three winters, although 1993 and 1994 differed most (1995 was intermediate). One of the striking features was the heterogeneity in patterns among species, families and foraging guilds over the three winters: some taxa (guilds) showed significantly higher densities in the middle year (1993 < 1994 > 1995), others increased monotonically (1993 < 1994 < 1995), while others increased from 1993 to 1994 and maintained those densities in 1995. The species showing significantly higher densities in 1994 were mostly nectarivorous, which seemed to accord with profuse and sustained flowering by Eucalyptus cypellocarpa in 1994 alone. The results are discussed in the context of non-equilibrial community dynamics, large- versus small-scale processes, and the implications of this magnitude of variation in unperturbed forests for environmental monitoring and impact assessments.     

Effects of a trawling moratorium on the breeding success of the Yellow-legged Gull Larus cachinnans

The establishment of a two month commercial fishing moratorium, which overlapped each year with different stages of the breeding cycle of the Yellow-legged Gull Larus cachinnans at the Ebro Delta, Spain, provided the opportunity of testing the effects of food limitation on the breeding success of this species. The study was carried out in 1993, when the chick rearing stage occurred with normal commercial fishing activity and in 1994, when the chick rearing stage overlapped with the trawling moratorium. We recorded diet of the chicks, breeding phenology, clutch size, egg volume, hatching success and productivity of adult birds. There was a highly significant difference in the diet of the chicks between the two years and significantly lower productivity in 1994, whilst the other parameters examined did not change. These results show that a dependence on discards from commercial fishing activities may be a limiting factor in the breeding success of this seabird.     

Short-term and long-term effects of food supply on parasite burdens in Tawny Owls, Strix aluco

1. The relationships among food supply (Field Voles, Microtus agrestis ), reproduction and blood parasites was investigated in Tawny Owls, Strix aluco , in Kielder Forest, Northumberland, in 1994 and 1995. Vole populations were significantly lower in 1995 than in 1994.
2. Birds did not lose parasites after initial infection, and the level at which infections were maintained was characteristic of individual birds.
3. In 1994, the number and intensity of parasites was higher in adult owls that had experienced low food supply when they themselves were reared. This indicated that food supplied to chicks in the nest has a long-term effect on the parasite burden of adults.
4. In addition, there was evidence that parasite burdens of adults were influenced by their current food supply. Birds that suffered a decline in food abundance on their territories between 1994 and 1995 showed an increase in parasite load over the same period. In 1995, there was also a significant negative correlation between the parasite loads of owls and vole abundance on their territories.
5. The best predictor of parasite number of chicks reared in 1995 was the parasite load of their fathers. The parasites chicks developed were not the parasites with which their fathers were heavily infested. This result could be due to inherited immunity.
6. Our results indicated that food resources should be measured when investigating interactions between parasites and their hosts, and that offspring quality as well as quantity might suffer when food abundance is low.     

Impact of food abundance, diet and food quality on the breeding of the fruit pigeon, Parea Hemiphaga novaeseelandiae chathamensis, on Chatham Island, New Zealand

Breeding and diet of Parea Hemiphaga novaeseelandiae chathamensis were studied in relation to food abundance and quality on Chatham Island from 1991 to 1994. Although pairs were found breeding in all months, they nested predominantly during winter and spring (June-November). The timing of the nesting season, the proportion of pairs that bred and the number of chicks reared per pair varied between nesting seasons. During the 1992–1993 and 1994–1995 nesting seasons, all pairs nested, and many pairs reared two chicks, often involving clutch overlap (58% of 12 cases in 1992–1993, 37% of eight cases in 1994–1995). In 1993–1994, when fruit was scarce, nesting began 2 months later, only 44% of pairs nested and no pairs attempted to rear a second chick. Prior to and during the productive nesting seasons (1992–1993, 1994–1995), the diet of Parea consisted mainly of fruit, particularly that of Matipo Myrsine chathamica in autumn (March-May) and Hoho Pseudopanax chathamicus in winter and spring. Nutrient analyses of the main Parea foods showed that the pulp of these fruit were rich in lipids and available carbohydrates compared with those in foliage foods. Heavy fruiting of Matipo and Hoho promoted early nesting and prolonged nesting for 6 months, including nesting during winter.     

Mass stranding of wedge-tailed shearwater chicks in Hawaii.

Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies.     

Supplementary feeding increases Common Buzzard Buteo buteo productivity but only in poor‐quality habitat

Temporal heterogeneity in the effects of food supply during the breeding season on the productivity of the Common Buzzard Buteo buteo was investigated in a supplementary feeding experiment. Pairs were fed artificially (1) before egg‐laying, (2) after chicks hatched and (3) continuously throughout the season, and compared with (4) unfed controls. Pairs fed before egg‐laying had marginally larger clutches than those not fed, but lay date, egg volume and weight, brood size and hatching success were unaffected. Territorial quality had far greater effects, with pairs nesting in low‐quality habitats (bog, scrub and semi‐natural grassland) laying later and having lower hatching success, smaller broods and fewer fledglings than those in more productive agricultural landscapes. Supplementary feeding after egg hatching neutralized the negative effect of poor habitat, resulting in fed birds having significantly more fledglings. This study emphasizes the importance of food availability when provisioning chicks in suboptimal habitats and has implications for the success of diversionary feeding in reducing game losses to Buzzards.     

Foraging movements of the Shy Albatross Diomedea cauta breeding in Australia; implications for interactions with longline fisheries

Satellite telemetry was used to identify the foraging zones of Shy Albatrosses Diomedea cauta breeding at two sites off Tasmania, Australia (Albatross Island in western Bass Strait and Pedra Branca to the south) to assess their level of interaction with longline fisheries. Adult birds from both colonies fed locally both in and outside the breeding season. Breeding birds from Albatross Island foraged over the Australian continental shelf or slope waters off northwest Tasmania, while those from Pedra Branca foraged between the colony and the southeastern edge of the continental shelf. The distances travelled by the birds and the duration of their foraging trips varied during the breeding cycle and tended to decrease as eggs approached hatching. Adults which were tracked near the end of the breeding season (March-April, n = 7 birds) deserted their chicks prematurely, and while dispersing further than incubating or brooding birds, they remained over the continental shelf and slope waters off southeast Australia. Home range analyses indicated 41% overlap between foraging zones of birds during successive breeding stages. Dispersal during the postbreeding period extended the foraging zones with less overlap between individuals (10% for Albatross Island and 19% for Pedra Branca). The recent contraction of the Japanese Southern Bluefin Tuna longline fishery to the south and east coasts of Tasmania has resulted in extensive overlap with adult Shy Albatrosses from Pedra Branca, but appears to pose a minimal threat to adult birds from Albatross Island. Coupled with the concomitant increase in the Australian domestic tuna longlining industry, adult Shy Albatrosses from southern Tasmania (Pedra Branca and the Mewstone) are vulnerable to incidental capture through out their annual cycle.     

Responses of <Emphasis Type="Italic">Pygoscelis adeliae</Emphasis> and <Emphasis Type="Italic">P. papua</Emphasis> populations to environmental changes at Isla 25 de Mayo (King George Island)

As part of a monitoring study of Adélie and Gentoo penguin colonies, birds occupying nests with eggs and chicks in crèches were counted annually from the 1995/1996 to the 2006/2007 seasons at Stranger Point, Isla 25 de Mayo (King George Island), Antarctica. During the study period the Adélie penguin population showed a decrease of 62%. The number of chicks in crèches followed a similar trend, the smallest number occurring in 2002, when it was 63% lower than in 1995/1996. In contrast, the Gentoo breeding population size increased by 68%, while chicks produced increased by 63%. Despite the opposing trends in population size between species, there was a positive relation in their interannual variation, although the extent, and for some years the direction, of the change observed always favoured Gentoo penguins. Breeding success (chicks in crèches/nests with eggs) fluctuated between 0.65 and 1.26 for Adélies and between 0.76 and 1.27 for Gentoo penguins, and did not differ significantly between species. The similar breeding success of these species suggests that the contrasting population trends observed were driven by factors operating over winter. We suggest that current changes in environmental conditions may affect adult birds of both species during the previous winter with different intensity but in a roughly similar way, but that juvenile survival of both species and thus the recruitment of new breeders might be affected differentially, with a much lower survival rate of juvenile Adélie penguins.     

Individual variability of behavioural responses by Wandering Albatrosses (Diomedea exulans) to human disturbance

Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.

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Diet of the King Penguin Aptenodytes patagonicus during three summers at South Georgia

King Penguins Aptenodytes patagonicus which were rearing chicks were studied during three summers from November 1991 to March 1994 at South Georgia. Stomach samples ( n =115) collected by flushing had a mean mass of 1308 g. Fish mass was allocated to each species based on the relationship between fish mass and otolith length. Three mesopelagic lanternfishes (Myctophidae), Krefftichthys anderssoni, Electrona carlsbergi and Protomyctophum choriodon , dominated the diet both by numbers and mass. They were small fish with mean mass of 3–7 g. Overall, K. anderssoni dominated the diet in terms of numbers and mass. Although Barracudina Notolepis coatsi occurred in <3% of the diet by numbers, it was large (106 g) and was second most important in terms of mass. Squid represented <3% of the diet by mass. Although the chick-rearing success was poor in the 1993–1994 summer, meal size was not reduced but foraging trips were longer. In the 1993–1994 summer, a larger proportion of the otoliths were not identifiable because they were more completely digested. Fewer otoliths were identified as being those of K. anderssoni , but we argue that about 90% of the unidentified otoliths were K. anderssoni. There was also more squid and N. coatsi in the diet during the poor summer. A consistent trend was that P. choriodon was rare or absent in early summer but more important later in the year, and at the end of 1992–1993, it was the dominant prey. We conclude that myctophid fish, especially K. anderssoni , are the main summer prey of King Penguins rearing chicks at South Georgia, as found in other recent studies in the Southern Ocean.