The population of the recently-described Whenua Hou diving petrel Pelecanoides whenuahouensis comprises c. 200 adults that all breed in a single 0.018 km2 colony in a dune system vulnerable to erosion. The species would therefore benefit from the establishment of a second breeding population through a translocation. However, given the small size of the source population, it is essential that translocations are informed by carefully targeted monitoring data. We therefore modelled nest survival at the remaining population in relation to potential drivers (distance to sea and burrow density of conspecifics and a competitor) across three breeding seasons with varying climatic conditions as a result of the southern oscillation cycle. We also documented breeding phenology and burrow attendance, and measured chicks, to generate growth curves. We estimated egg survival at 0.686, chick survival at 0.890, overall nest survival at 0.612, and found no indication that nest survival was affected by distance to sea or burrow density. Whenua Hou diving petrels laid eggs in mid October, eggs hatched in late November, and chicks fledged in mid January at c. 86% of adult weight. Burrow attendance (i.e. feeds) decreased from 0.94 to 0.65 visits per night as chicks approached fledging. Nest survival and breeding biology were largely consistent among years despite variation in climate. Nest survival estimates will facilitate predictions about future population trends and suitability of prospective translocation sites. Knowledge of breeding phenology will inform the timing of collection of live chicks for translocation, and patterns of burrow attendance combined with growth curves will structure hand-rearing protocols. A tuhinga whakarāpopoto (te reo Māori abstract) can be found in the Supplementary material.

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.

Albatrosses are among the most threatened groups of seabirds with the main land-based threats being alien invasive species, human disturbance and habitat degradation. Disease outbreaks in Antarctic and sub-Antarctic seabird populations are uncommon, but in the past few decades there has been an increase in reported cases. The sub-Antarctic Prince Edward Islands (46°S, 37°E) in the south-western Indian Ocean provide breeding grounds for many seabird species, including 44% of all wandering albatrosses (Diomedea exulans L.). In 2015, five wandering albatrosses and two penguins (Eudyptes chrysocome Forster and Aptenodytes patagonicus Miller) with pox-like lesions were observed on Marion Island, the larger of the two Prince Edward Islands. Despite intensive study of the wandering albatross population since the 1980s, the only previous records of such lesions are one case in 2006 and another in 2009 in white-chinned petrels (Procellaria aequinoctialis L.). Molecular and phylogenetic analysis of tissue samples from two albatross chicks confirmed the presence of avian pox virus (Avipoxvirus). This highlights the need for research into the diseases present on sub-Antarctic islands, for strict controls to limit the risk of accidental introduction of diseases through human activities and the need for effective conservation measures in the event of an outbreak.

Until recently, the spectacled petrel Procellaria conspicillata Gould was listed as Critically Endangered due to its small population size and ongoing incidental mortality on fishing gear. Surveys at its sole breeding locality, Inaccessible Island in the central South Atlantic Ocean, indicated that the population increased from 1999–2004, resulting in the species being down-listed to Vulnerable. We repeated the census of breeding spectacled petrels during the early incubation period in October–November 2009. Numbers of burrows increased by 55% from 2004–09, with increases in all count zones, and the greatest changes in peripheral populations. Burrow occupancy estimates remained high, averaging 81% during one-off checks. Our best estimate of the population in 2009 was 14 400 pairs, continuing the c. 7% per year increase inferred since the 1930s following the disappearance of introduced pigs. This confirms the rapid recovery of this species despite ongoing mortality on fishing gear. Our results suggest that at least some procellariiforms are able to sustain strong growth rates in the face of fishing mortality when colony based threats are removed.

Chick feeding in common diving petrels (Pelecanoides urinatrix exsul) and South Georgia diving petrels (P. georgicus) was studied on Bird Island, South Georgia. Complete chick meals removed from the proventriculus of adults averaged 25.5 g (n = 32) for common diving petrels (17.6% of adult mass) and 23.3 g (n = 24) for South Georgia diving petrels (20.2% of adult mass); neither contained stomach oils. The sum of the positive mass increments during overnight weighings (SUM) averaged 48.6 g for common diving petrel chicks (n = 78 chick nights) and 41.6 g for South Georgia diving petrel chicks (n = 78 chick nights). Average adult feeding frequencies were 0.95 meals day−1 and 0.92 meals day−1, respectively. Relative meal size in diving petrels was similar to that of other procellariiforms, but SUM averaged about twice that of other petrels. The lower conversion efficiency of meals to body mass in diving petrel chicks reflects the absence of stomach oils in the diet. Higher chick feeding frequency and lower variance in SUM are consistent with the hypothesis that diving petrels forage nearshore on reliable food supply compared with other procellariiforms.

Chick growth and food provisioning of northern fulmars Fulmarus glacialis were studied at Fair Isle, Shetland, in 2 years of contrasting environmental conditions. Low sandeel Ammodytes marinus availability resulted in very low breeding success in many seabirds in Shetland in 1998, whereas breeding success in 1997 indicated a normal season. Fulmars at Fair Isle experienced lower chick survival in 1998 than in 1997. There were also significant differences in diet and food provisioning in the 2 years; sandeels were the most abundant prey items in 1997, but were completely absent from the diet in 1998. High nestling mortality occurred shortly after hatching in 1998. Those chicks that survived this episode had previously been heavier for their age, and remained heavy throughout development in comparison to chicks in 1997, despite a continued absence of sandeels from the diet. Surviving chicks in 1998 were subsequently fed comparatively small meals at frequent intervals, but with no overall difference in the amount of food delivered. We discuss the implications of differential mortality and resulting growth patterns for the use of seabird breeding parameters to monitor marine environments.