Marcel Klaassen

With multiple Declared Areas nationally, offshore wind energy is poised to expand within Australia’s iconic coastal and marine environments. We argue that the central obstacle to credible environmental assessment of offshore wind is not a shortfall of effort or rigour within individual assessments, but a structural feature of how assessment is legally constituted. Australia’s principal national environmental law, the Environment Protection and Biodiversity Conservation Act 1999, protects species across their distribution, yet project-level assessments investigate impact only within or near a development’s footprint. We identify four structural problems, namely unmanaged cumulative impacts, mismatched regulatory and ecological scales, an incomplete species list, and a causal-evidence gap that project-level assessment cannot close, which limit our capacity to detect and attribute development impacts on far-ranging, long-lived marine mammals, birds, and sharks, charismatic species whose life histories make them particularly sensitive to reductions in survival and reproductive success. We recommend addressing these shortfalls through a coordinated, independent, and openly accessible national program of marine and coastal biodiversity science, funded through a pooled industry levy rather than project-by-project commissioning, and coupled to strategic environmental assessment. Australia’s offshore wind sector is at an early enough stage to build this architecture from the outset, so that renewable development and environmental stewardship advance together rather than in tension. Done well, this might help build public trust in offshore wind domestically and position Australia as a leader in international best practice in offshore environmental research and monitoring, offering a model for nations whose offshore wind sectors are emerging.

The panzootic caused by high pathogenicity avian influenza (HPAI) H5N1 clade 2.3.4.4b has been devastating for animals, globally. Despite global spread, the virus remains absent in Oceania. Herein we report the results of our fourth year of enhanced migratory bird surveillance, coinciding with the spring migration of wild birds in 2025; none of the 847 migratory wild birds or 38 marine mammals were positive for HPAI H5N1, although we did detect LPAI. Surveillance remains a critical tool for HPAI H5N1 response, with early detection and rapid response being critical to mitigate the impacts of this virus on animal, environment and human health.

The current panzootic of high pathogenicity avian influenza (HPAI) H5N1 has been catastrophic for wildlife, and following a significant sweep, clade 2.3.4.4b is found in every region aside from Oceania. Herein, we report the results of our third year of targeted surveillance of incoming migratory seabirds and shorebirds into Australia. We did not find evidence of HPAI H5N1 in any of the birds tested, and there were no reports of HPAI H5N1 in wildlife tested through other surveillance schemes in 2024. Unlike previous years, we detected a diversity of low pathogenicity avian influenza (LPAI) viruses in shorebirds. Through phylogenetic analysis we revealed that the H3N7 and H4N7 viruses recovered from Red-necked Stints were complex mosaic viruses, comprising segments of Eurasian, Australian shorebird, and Australian waterfowl segments. A H1N7 virus detected comprised a wholly Eurasian introduction, confirming this route for avian influenza viruses into Australian ecosystems. These results provide further evidence for the key role of long-distance migratory shorebirds in introducing novel LPAI viruses into Oceania. While our focus on northern migration routes remained appropriate for HPAI H5N1 surveillance in 2024, the continued spread of HPAI H5N1 to sub-Antarctic Islands demands consideration of a potential southern incursion route for Oceania in future.

Morphological changes concurrent with climate change are increasingly identified in birds, often through decreasing body size and increasing appendage size. Such changes could have thermoregulatory implications, through the improved surface area to body ratio they provide. Due to the role of bird wings in thermoregulation, wing length relative to body mass may be changing as another form of shape‐shifting, where increased relative wing length may facilitate increased heat loss as climates warm. We investigated changes in relative wing length on a dataset of nearly 20 000 juvenile shorebirds from 11 species over the past four decades, to determine changes in morphology and whether these are linked to developmental temperatures. Overall, across species, we found that relative wing length increased across the 43‐year study period in populations migrating to tropical northern Australia but not in those migrating to temperate southern Australia. Furthermore, we found that changes in relative wing length were not driven by immediate responses to high temperature at the breeding ground during juvenile growth. These results may suggest that relative wing length increases occur in shorebirds occupying already warm climates, where they might potentially be more thermally challenged under further warming, but that such changes are not occurring through plastic mechanisms during development.

MicroRNAs (miRNAs) are highly conserved small noncoding RNAs that regulate gene expression post‐transcriptionally. Circulating miRNAs – miRNAs that have been released from cells and circulate in the bloodstream – are relatively stable and interesting molecules for wildlife research, where they may form a proxy for gene expression as a function of the animal's state under a variety of environmental challenges. Aiming at providing initial baseline data on the circulating miRNAome in avian wildlife, we assessed the miRNA profiles of wild ruddy turnstones Arenaria interpres on their Australian non‐breeding grounds. The ruddy turnstone is a long‐distant migrant and a significant reservoir species for low pathogenic avian influenza virus (LPAIV). We therefore investigated both LPAIV‐infected and uninfected individuals for their specific miRNA profiles to potentially elucidate the species' molecular mechanisms underlying its response to LPAIV infection. De novo miRNA characterisation in the ruddy turnstone genome identified 161 conserved and two novel, bird‐specific miRNAs, with liver‐enriched miRNA‐122 being the most abundant. Z chromosome‐linked miR‐2954‐3p was significantly more abundant in serum from males (ZZ) than from females (ZW). Furthermore, we found a sex‐ and age‐associated effect of LPAIV infection on miRNA abundance in serum samples, including one novel miRNA. This circulating miRNA signature may reflect sex‐ and age‐specific differences in the host response, indicating that circulating miRNAs could serve as a valuable non‐destructive analytical tool for enhancing our understanding of avian infections in a wildlife context and should be explored further.

Animals are predicted to shrink and shape‐shift as the climate warms, declining in size, while their appendages lengthen. Determining which types of species are undergoing these morphological changes, and why, is critical to understanding species responses to global change, including potential adaptation to climate warming. We examine body size and bill length changes in 25 shorebird species using extensive field data (> 200,000 observations) collected over 46 years (1975–2021) by community scientists. We show widespread body size declines over time, and after short‐term exposure to warmer summers. Meanwhile, shorebird bills are lengthening over time but shorten after hot summers. Shrinking and shape‐shifting patterns are consistent across ecologically diverse shorebirds from tropical and temperate Australia, are more pronounced in smaller species and vary according to migration behaviour. These widespread morphological changes could be explained by multiple drivers, including adaptive and maladaptive responses to nutritional stress, or by thermal adaptation to climate warming.

Changes to body size and shape have been identified as potential adaptive responses to climate change, but the pervasiveness of these responses has been questioned. To address this, we measured body and appendage size from 5013 museum bird skins of 78 ecologically and evolutionary diverse Australian species. We found that morphological change is a shared response to climate change across birds. Birds increased relative bill surface area, tarsus length, and relative wing length through time, consistent with expectations of increasing appendage size as climates warm. Furthermore, birds decreased in absolute wing length, consistent with the expectation of decreasing body size in warmer climates. Interestingly, these trends were generally consistent across different diets and migratory and thermoregulatory behaviors. Shorter term responses to higher temperatures were contrary to long‐term effects for appendages, wherein relative appendage size decreased after hotter years, indicating the complex selective pressures acting on birds as temperatures rise with climate change. Overall, our findings support the notion that morphological adaptation is a widespread response to climate change in birds that is independent of other ecological traits.