Biology subjects

Wilhelm, S. I.

Publications and source records attributed to Wilhelm, S. I..

6 recordsLinked to original sources

bioRxiv2024

Under Cover of Darkness: Refuge from Artificial Light at Night may Mitigate Risks to Stranded Seabirds

Artificial light at night is an anthropogenic pollutant that has wide-ranging effects on wildlife. Fledgling seabirds of the order Procellariiformes exhibit phototaxis toward artificial lights on their first flights from the nest, causing them to become grounded in human settlements where they are subject to increased risk of predation. Limited evidence suggests that certain light types may be less attractive than others, yet there is also evidence for an aversion to light under certain circumstances. We investigated differences in phototactic behaviour, activity level, and shelter-seeking behaviour of grounded Hydrobates leucorhous (Leachs storm-petrel) fledglings exposed to artificial light in three experiments: a Y-maze choice experiment, an open field test, and a modified open field test with a hide box provided ("Safe Haven test"). When provided with combinations of different light types in the Y-maze, storm-petrels typically remained stationary in the darkest part of the apparatus and exhibited no response toward one light type over another. This was consistent with results from the open field test, in which individuals were less active in darkness than when exposed to two out of three light conditions (Warm White Light-Emitting Diode and High Pressure Sodium). More than half of birds entered the hide box in light conditions, compared to none in the dark. Considered together, our results indicate Leachs storm-petrel fledglings exhibit photophobic behaviour after stranding, which may be part of a behavioural strategy to avoid predation. Further, we demonstrate the utility of providing hide boxes to protect stranded seabird fledglings in locations where lighting cannot be eliminated or where rescue efforts may be limited in spatial or temporal coverage. However, hide boxes would have limited utility in dark locations. Hide boxes constitute a novel mitigation measure that merits future testing for its ability to reduce stranding-induced mortality, especially in imperiled procellariiform species. LAY SUMMARYO_LIGlobally, fledglings of many seabird species become stranded in towns and at industrial sites near their breeding colonies C_LIO_LIStrandings are thought to be caused by attraction to lights, although some species appear to avoid light C_LIO_LIWe tested behavioural responses and activity levels of Leachs storm-petrel fledglings toward several different light types C_LIO_LIWhen presented with different types of light in a choice experiment, most birds remained stationary C_LIO_LIFledglings were more active in warm-hued lights than in darkness C_LIO_LIBirds sought shelter when it was provided in light conditions, but not when provided in darkness C_LIO_LIOur results suggest that rescue programs targeting Leachs storm-petrels should include searches in dark, hidden locations where fledglings are likely to hide, and support the use of small shelters to protect stranded seabirds when lights cannot be turned off C_LI

animal behavior and cognition↗

bioRxiv2024

Seabird and sea duck mortalities were lower during the second breeding season in eastern Canada following the introduction of Highly Pathogenic Avian Influenza A H5Nx viruses

H5N1 clade 2.3.4.4b viruses have caused significant mortality events in various wild bird species across Europe, North America, South America, and Africa. In North America, the largest impacts on wild birds have been in eastern Canada, where over 40,391 wild birds were reported to have died from highly pathogenic avian influenza (HPAI) between April and September 2022. In the year following, we applied previously established methods to quantify total reported mortality in eastern Canada for a full year October 2022, to September 2023. In this study, we (i) document the spatial, temporal and taxonomic patterns of wild bird mortality in the 12 months that followed the mass mortality event in the summer of 2022 and (ii) quantify the observed differences in mortality across the breeding season (April to September) of 2022 and 2023. In eastern Canada, there was high uncertainty about whether 2023 would bring another year of devastating HPAI-linked mortalities. Mortalities in the breeding season were 93% lower in 2023 compared to 2022 but encompassed a more taxonomically diverse array of species. We found that mortalities in the fall and winter (non-breeding season) were dominated by waterfowl, while mortalities during the spring and summer (breeding season) were dominated by seabirds. Due to a low prevalence of HPAI among the subset of tested birds, we refrained from broadly attributing reported mortalities in 2023 to HPAI. However, our analysis did identify three notable mortality events linked to HPAI, involving at least 1,646 Greater Snow Geese, 232 Canada Geese, and 212 Northern Gannets. This study emphasizes the ongoing need for H5NX surveillance and mortality assessments as the patterns of mortality in wild populations continue to change.

ecology↗

bioRxiv2024

Navigating the Night: Effects of Artificial Light on the Behaviour of Atlantic Puffin Fledglings

Every year in Newfoundland, young Atlantic Puffins (Fratercula arctica) departing their nests at night for the first time become stranded in towns near their breeding colonies, a phenomenon thought to be caused by attraction toward artificial light. To test this hypothesis, we conducted three behavioural experiments. First, we illuminated beaches near a breeding colony to determine whether more fledglings would become stranded in illuminated versus dark conditions. Next, we conducted a Y-maze experiment to test stranded fledglings for phototactic behaviour in general and for preferences among High Pressure Sodium (HPS), Warm White Light-Emitting Diode (LED), Cool White LED, Blue LED, and Orange LED light. Lastly, we quantified activity levels of stranded fledglings in an open field test during exposure to several different light types. We found significantly more fledglings stranded when beaches were illuminated, and fledglings significantly preferred light over darkness in the Y-maze, supporting our hypothesis that Atlantic Puffin fledglings become stranded due to light attraction. Fledglings displayed no preferences for certain light types over others in the Y-maze, potentially suggesting that strandings in this species may not be mitigable by changing the streetlight type in stranding-prone towns. Interestingly, fledglings exhibited higher activity levels in darkness and HPS light than in LED light, potentially holding implications for rescue, rehabilitation, and husbandry programs. Overall, our findings demonstrate that the only evidence-based strategy for the reduction of Atlantic Puffin strandings remains to be the reduction of coastal artificial lighting; however, further research is needed to determine if aspects of artificial light besides bulb type may be altered to effectively reduce light attraction in this species.

animal behavior and cognition↗

bioRxiv2024

Geographic, ecological, and temporal patterns of seabird mortality during the 2022 HPAI H5N1 outbreak on the island of Newfoundland

Highly pathogenic avian influenza (HPAI) H5N1 caused mass seabird mortality across the North Atlantic in 2022. Following outbreaks in Europe, the first case in North America was detected on the island of Newfoundland (NFLD), Canada in November 2021, before spreading through all North American flyways. During the following breeding season, NFLD experienced the second-highest number of seabird mortalities in Canadian provinces. Surveys and citizen reports identified 13543 seabird mortalities from April to September 2022. Many carcasses occurred on the west coast of NFLD in May and June 2022. Reported mortalities peaked in July along the southeastern coast. In August and September, mortalities were concentrated along the northeastern coast. With the exception of two colony surveys, reported mortalities decreased in September. Most mortality was found among Northern Gannet (6622), Common Murre (5992), Atlantic Puffin (282), and Black-legged Kittiwake (217). Using comprehensive knowledge of seabird ecology, we formulated exploratory hypotheses regarding traits that could contribute to mortality. Species differences in mortality were most strongly associated with nesting density, timing of breeding, and at-sea overlap with allospecifics from other colonies. Unprecedented seabird mortality and ongoing transmission within the circulating avian influenza viruses highlight the need for continued monitoring and development of conservation strategies.

zoology↗

bioRxiv2024

Wild bird mass mortalities in eastern Canada associated with the Highly Pathogenic Avian Influenza A(H5N1) virus, 2022

In 2022, a severe outbreak of clade 2.3.4.4b Highly Pathogenic Avian Influenza (HPAI) H5N1 virus resulted in unprecedented mortality among wild birds in eastern Canada. Tens of thousands of birds were reported sick or dead, prompting a comprehensive assessment of mortality spanning the breeding season between April 1 and September 30, 2022. Mortality reports were collated from federal, Indigenous, provincial, and municipal agencies, the Canadian Wildlife Health Cooperative, non-governmental organizations, universities, and citizen science platforms. A scenario analysis was conducted to refine mortality estimates, accounting for potential double counts from multiple sources under a range of spatial and temporal overlap. Correcting for double counting, an estimated 40,966 wild birds were reported sick or dead in eastern Canada during the spring and summer of 2022. Seabirds and sea ducks, long-lived species that are slow to recover from perturbations, accounted for 98.7% of reported mortalities. Mortalities were greatest among Northern Gannets (Morus bassanus; 26,193), Common Murres (Uria aalge; 8,133), and American Common Eiders (Somateria mollissima dresseri; 1,945), however, these figures underestimate total mortality as they exclude unreported deaths on land and at sea. In addition to presenting mortality estimates, we compare mortalities with known population sizes and trends and make an initial assessment of whether population-level impacts are possible for the Northern Gannet, a species that has suffered significant global mortality, and two harvested species, Common Murre and American Common Eider, to support management decisions. We hypothesize that population-level impacts in eastern Canada are possible for Northern Gannets and American Common Eiders but are unlikely for Common Murres. This study underscores the urgent need for further research to understand the broader ecological ramifications of the HPAI outbreak on wild bird populations.

zoology↗

bioRxiv2023

Reduction of coastal lighting decreases seabird strandings

Leachs Storm-Petrels (Hydrobates leucorhous) are small, threatened seabirds with an extensive breeding range in the North Atlantic and North Pacific Oceans. The Atlantic population, which represents approximately 40 - 48% of the global population, is declining sharply. Positive phototaxis, the movement towards artificial light at night (ALAN), is considered to be a key contributing factor. Many seabirds exhibit positive phototaxis, which can result in stranding on land. The Leachs Storm-Petrel is the seabird most often found stranded around ALAN in the North Atlantic, though there is little experimental evidence showing that reducing ALAN will decrease the occurrence of stranded storm-petrels. During a two-year study at a large, brightly illuminated seafood processing plant adjacent to the Leachs Storm-Petrels largest colony, we compared the number of birds that stranded when the lights at the plant were turned on versus off. We recorded survival, performed carcass counts of both adults and juveniles, and released any rescued individuals. Turning the lights off reduced strandings by 39.15% (CI: 11.45% - 58.19%). The peak stranding period occurred from 25 September to 28 October, and most of the stranded birds were fledglings. These results provide evidence to support the widespread reduction and modification of coastal artificial light, especially during avian fledging and migration periods.

animal behavior and cognition↗