Images of deceased shearwaters on beaches in southeastern Australia, from the publication

Jennifer Lavers (Adrift Lab, Underwood, Tasmania, Australia) and colleagues have published open access in the journal Conservation Biology, reporting that marine heat waves resulted in an estimated 629 000 seabird deaths, notably of two Australian shearwater species, in 2023–2024.

The paper’s abstract follows:

“Marine heat waves detrimentally affect a range of marine species, including seabirds, and are increasing in frequency and severity.  When thousands of dead seabirds wash up on beaches, the public becomes concerned.   However, the number of dead birds recorded on beaches is only a fraction of the total mortality; most birds perish at sea. As a result, estimates of total mortality are scarce, and this impedes the ability to determine how such mortality events affect populations.  Community science programs can greatly enhance the geographic or temporal scale of studies, which can be critical when mortalities or changes take place over large distances or many months.  Using three community science data repositories, we examined the number and composition of seabirds found dead on beaches in eastern Australia during the 2023–2024 marine heat wave.  Mortality estimation models developed for other sectors were refined using measures of searcher efficiency and carcass persistence for beach-washed birds. Total mortality of sable shearwaters (Ardenna carneipes) and short-tailed shearwaters (Ardenna tenuirostris) was >13,900 and >608,000, respectively.  The loss of these birds, in total more than 629,000 individuals, highlights the increasingly perilous marine environment in which many marine species now exist.”

Reference:

Lavers, J.J., Fulton, W., Stuckenbrock, S. & Bond, A L. 2026.  Estimating the total mortality of seabirds following a marine heat wave.  Conservation Biology doi.org/10.1111/cobi.70273.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 28 April 2026

Streaked Shearwaters in a breeding colony

Helen Pružina (School of Biological and Environmental Sciences, University of Stirling, United Kingdom) and colleagues have published in the open-access journal Marine Ornithology on young Near Threatened Streaked Shearwaters Calonectris leucomelas socializing ashore during the breeding season.

The paper’s abstract follows:

“Many seabird species have a long breeding-deferral period, during which individuals mature and spend most of their time at sea, making them particularly difficult to study.  In some species, immatures are known to start visiting colonies before reaching adulthood, presumably to learn the behaviours required to secure a nest and mate for future breeding.  However, immature colony attendance remains undocumented in many species, particularly those that are difficult to observe, such as nocturnal, cavity-nesting species and species in which immatures are indistinguishable from adults.  Here, we studied the attendance patterns and behaviour of Streaked Shearwaters Calonectris leucomelas on Awashima Island, Japan, during the chick-rearing period.  We logged the number and duration of visits to the colony and assessed the potential influence of moonlight on these metrics.  We found a weak effect of moonlight on attendance but identified two types of nocturnal visits: one in which birds spent little time above ground and the other in which birds spent hours sitting on the surface.  During the latter, birds often gathered in groups and either rested or engaged in behaviours such as allopreening, fighting, calling, and digging burrows.  These longer visits sharply decreased in numbers well before the end of the chick-rearing period, and we suggest these visits are most likely undertaken by immatures, based on behaviours documented in other shearwater species.  The presence of immature Streaked Shearwaters at the colony during the breeding period has implications for the population ecology of the species and highlights the potential impact of predators and other at-colony risks on an additional age class of Streaked Shearwaters, beyond adults and chicks.”

Reference:

Pružina, H.M., Shoji, A., Shirai, M., Matsumoto, S., Yoda, K. & Fayet, A L. 2026.  Evidence for colony attendance by immature Streaked Shearwaters Calonectris leucomelas during the chick-rearing period.  Marine Ornithology 54: 79-86.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 27 April 2026

 A breeding Black-browed Albatross on Kerguelen Island, photograph by Deborah Pardo

Bertille Mohring (School of Environmental Sciences, University of Liverpool, UK) and colleagues have published open access in the journal Ecology Letters on differing life-history strategies of Black-browed Albatrosses Thalassarche melanophris on Bird Island in the South Atlantic and Kerguelen Island in the southern Indian Ocean.

The paper’s abstract follows:

“Individuals face a trade-off between allocating resources to reproduction or self-maintenance, yet the drivers of the existence and strength of such trade-off have been hard to determine.  Environmental conditions are thought to play a crucial role, as long-lived species are predicted to favour more precautionary life-history strategies in variable environments.  However, empirical evidence remains limited.  Using long-term monitoring of two black-browed albatross Thalassarche melanophris populations, we investigated variation in life-history strategies under contrasting environmental conditions, through reproductive senescence.  In more variable environments, individuals displayed generally slower life histories (i.e., slow, late-onset senescence) and greater among-individual variation in life-history strategies.  Interestingly, earlier and faster reproductive senescence correlated with higher lifetime reproductive success regardless of environmental variability, suggesting that either faster life histories incur higher fitness or successful reproduction accelerates reproductive senescence.  These findings reveal how environmental variability shapes life-history strategies, highlighting potential responses to increasing environmental variability in a changing world.”

With thanks to Karine Delord and Richard Phillips.

Reference:

Mohring, B., Potts, J.R., Wilson, A.J., Réale, D., Phillips, R.A., Weimerskirch, H., Barbraud, C., Bennison, D., Delord, K., Wood, A.G., Peroteau, S., Rouby, E., Ventura, F. & Patrick, S.C. 2026.  Environmental variability shapes life-history trade-offs within and between populations of a long-lived seabird.  Ecology Letters 29(4).  doi.org/10.1111/ele.70384.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 24 April 2026

Graphical abstract from the publication

Jumpei Okado (Graduate School of Environmental Studies, Nagoya University, Japan) with many coauthors have analysed blood mercury concentrations in more than 11 215 seabirds across 108 species, six of them albatrosses and 32 of other species within the Procellariiformes, publishing open access in the journal Science of The Total Environment.

“It provides the first biologically based estimate of mercury distribution in the ocean.  The study shows that mercury levels in seabirds vary with prey trophic level, body weight, and foraging depth.”

The paper’s abstract follows:

“Mercury (Hg) is a global contaminant that biomagnifies in marine food webs. Seabirds can serve as valuable bioindicators of marine Hg pollution due to their high trophic positions and broad distributions. However, the biological and spatial drivers of variation in seabird Hg levels remain unclear, and few studies have validated whether seabird-derived estimates of the spatial distribution of Hg are consistent with predictions from biogeochemical-ocean models. We conducted a global meta-analysis of total Hg (THg) concentrations in adult seabird blood. Based on our own fieldwork and a literature review, we compiled 478 mean THg values from 108 species representing >11,000 individuals. Blood THg increased in species feeding at higher trophic levels, with larger body mass, and those more likely to consume mesopelagic prey in oceanic waters. Additionally, blood THg might further increase in regions with low chlorophyll-a level, likely due to greater methylmercury uptake in areas with low-productivity. We subsequently developed models to predict global spatial variation in seabird blood THg, either from all species or only epipelagic prey feeders. Only our epipelagic prey feeder-based model showed a weak significant positive correlation with THg in particulate organic matter from biogeochemical-ocean models. However, the low correlation coefficient (r = 0.23) indicates potential discrepancies between the two models. We suggest that future studies adopt our integrative approach, combining biological data and large-scale modeling, to improve our understanding of global marine Hg pollution. Together, these findings clarify the biological and environmental drivers of Hg exposure in seabirds and highlight the value of seabirds for global monitoring of marine Hg pollution.”

With thanks to the World Seabird Union.

Reference:

Okado, J. et al. 2026.  Global drivers of variation in blood mercury of seabirds revealed by a meta-analysis.  Science of the Total Environment 1014. doi.org/10.1016/j.scitotenv.2025.181317.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 23 April 2026