In 2022, highly pathogenic avian influenza (HPAI) A(H5N1) virus clade 2.3.4.4b became enzootic and caused mass mortality in Sandwich Tern Thalasseus sandvicensis and other seabird species across north-western Europe. We present data on the characteristics of the spread of the virus between and within breeding colonies and the number of dead adult Sandwich Terns recorded at breeding sites throughout north-western Europe. Within two months of the first reported mortalities, 20,531 adult Sandwich Terns were found dead, which is >17% of the total north-western European breeding population. This is probably an under-representation of total mortality, as many carcasses are likely to have gone unnoticed and unreported. Within affected colonies, almost all chicks died. After the peak of the outbreak, in a colony established by late breeders, 25.7% of tested adults showed immunity to HPAI subtype H5. Removal of carcasses was associated with lower levels of mortality at affected colonies. More research on the sources and modes of transmission, incubation times, effective containment, and immunity is urgently needed to combat this major threat for colonial seabirds.

Between April 2008 and July 2015, we conducted a total of 18 trips on five different side-haul trawlers fishing within the Argentine Exclusive Economic Zone, monitoring 486 hauls. We observed 100% of the hauls and monitored trawl cables for 136.7 hours, about 5% of the trawl effort, to identify the levels of seabird bycatch from net entanglements and collisions with trawl cables. A total of 35 net entanglements of White-chinned Petrels Procellaria aequinoctialis, Great Shearwaters Ardenna gravis, Black-browed Albatrosses Thalassarche melanophris and Southern Royal Albatross Diomedea epomophora were recorded, all of which occurred during the autumn and winter. Additionally, 656 seabird collisions against trawl cables were recorded including 39 heavy, 96 medium and 521 light. Further, we recorded nine Black-browed Albatrosses and two Great Shearwaters potentially dead. Although in the study fishery the number of deaths in the trawl cables could surpass the number of birds incidentally killed in nets, the mortality rate caused by the latter type of interaction far exceeds those observed in nets from other trawl fisheries operating in the Patagonian Shelf. Fortunately, 26% of the seabirds entangled in the net were recovered and released alive, which indicates that awareness and training in safe bird handling and release may improve captured seabird survival rates. The main objectives of this work is to highlight a little-studied source of seabird mortality by entanglement, to generate discussion on potential technical mitigation measures for side-haul trawl fisheries, and to propose crew training in safe handling and release of seabirds as an immediate mitigation measure.

Cook’s Petrel Pterodroma cookii is an endemic New Zealand seabird that has experienced a large range decline since the arrival of humans and now only breeds on two offshore islands (Te Hauturu-o-Toi/Little Barrier Island and Whenua Hou/Codfish Island) at the extreme ends of its former distribution. Morphological, behavioural, and mitochondrial cytochrome oxidase 1 (CO1) sequence data led a previous study to recognise the two extant populations as distinct conservation management units. Here, we further examine the genetic relationship between the extant populations using two nuclear introns (β-fibint7 and PAX). Using one mitochondrial locus (CO1), we also investigate the past distribution of a single nucleotide polymorphism (SNP) that differentiates the modern populations using bone and museum skins sourced from within its former range across New Zealand’s North and South Islands. We found significant population genetic structure between the two extant Cook’s Petrel populations for one of the two nuclear introns (β-fibint7). The mitochondrial DNA CO1 analysis indicated that the SNP variant found in the Codfish Island population was formerly widely distributed across both the North and South Islands, whereas the Little Barrier Island variant was detected only in North Island samples. We argue that these combined data support the recognition of the extant populations as different subspecies. Previous names for these taxa exist, thus Cook’s Petrel from Little Barrier Island becomes Pterodroma cookii cookii and Cook’s Petrel from Codfish Island becomes P. c. orientalis. Furthermore, we suggest that both genetic and non-genetic data should be taken into consideration when planning future mainland translocations. Namely, any translocations on the South Island should be sourced from Codfish Island and future translocations on the North Island should continue to be sourced from Little Barrier Island only.

Commercial, shipborne tourism along the Antarctic Peninsula grew exponentially between 1989–90 and 2007–08, raising concern about the impact such activity may have on the environment of the region. Previous analyses of Antarctic tourism have focused narrowly on patterns of visitation and potential impacts at terrestrial landing sites. Here, using 19 years of passenger landing statistics and five years of reconstructed ship itineraries, we explore patterns of tourism activities in the Antarctic Peninsula region using a spatially explicit network theory analysis of ship itineraries. We find that passenger landings and marine traffic are highly concentrated at a few specific locations and that growth in tourism activity occurred disproportionally rapidly at these sites relative to growth in visitation of the Peninsula as a whole. We conclude by discussing the pros and cons of spatially concentrated tourism activity and the associated implications for ecosystem management.

Introduced rats depredate every life stage of island nesting seabirds, but the extent of predation is rarely quantified. Introduced black rat (Rattus rattus) and native deer mouse (Peromyscus maniculatus anacapae) predation on Xantus's murrelet (Synthliboramphus hypoleucus scrippsi) nests was experimentally quantified using artificial nests before and after rat eradication on Anacapa Island (California). The staged rat eradication programme provided experimental treatments: in 2002 rats were eradicated on one island (East Anacapa Islet) and remained on two islands (Middle and West Anacapa Islets), providing a control comparison, and, in 2003, rats were eradicated from the remaining islands (Middle and West Anacapa Islets). In 2002, 96% of artificial nests were depredated on control islands (rats present) with rats accounting for most predation. Nest predation on the treatment island (rats eradicated) in 2002 was significantly lower: 8% of artificial nests were depredated, mostly by endemic deer mice. In 2003, following rat eradication on the remaining islands (Middle and West Anacapa Islets), nest predation was reduced from 96% in 2002 to 3% of total nests in 2003. Predation of nests on East Anacapa Islet (rats eradicated in 2002) increased significantly due to reintroduction and recovery of native deer mouse populations, with 23% of artificial nests depredated. The inference is that rat predation on real Xantus's murrelet nests was responsible for the historically low nesting success and small population sizes of breeding murrelets on Anacapa Island. With rats removed, the hatching success of Xantus's murrelet chicks and the number of individuals nesting on Anacapa Island will increase dramatically. Artificial nest studies are particularly well suited to quantifying introduced rat impacts on hole and crevice nesting seabirds and can simultaneously serve as an effective monitoring tool to detect the presence of rats and the recovery of native nest predators.