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Nocturnal Flight Activity by Northern Gannets \u3ci\u3eMorus bassanus\u3c/i\u3e in Response to Predator Presence
No full textThe Northern Gannet Morus bassanus typically flies only during the day, with minimal flight activity following civil twilight. Here we document nocturnal flight activity by Northern Gannets in response to predation risk by Eastern Coyotes Canis latrans. Eight parental gannets were fitted with GPS/time-depth recorders on 15 July 2021 at mainland nest sites at Cape St. Mary’s, Newfoundland, Canada. Previously, among 506 foraging trips in 2019 and 2020 that were investigated using biologging, only two were initiated at night, suggesting nocturnal departures for foraging are very rare at this colony. Then, however, killings of chicks by coyotes occurred within our study plot on 24 July 2021. From 24 July to 20 August 2021, we recorded 51 instances of nocturnal departures from the colony during which individuals rested on the water overnight and returned to the colony by the following morning without foraging, which we deem to be a response to predator disturbance. The predation and nocturnal anti-predator flight behaviour recorded in this study is indicative of the risks associated with mainland nesting by colonial seabirds
At-Colony Behaviour of Great Black-backed Gulls \u3ci\u3eLarus marinus\u3c/i\u3e Following Breeding Failure
No full textTerritoriality for breeding sites comes at an energetic cost—individuals actively defend the site from competitors and potential predators, thus precluding themselves from self-maintenance (e.g., foraging, preening) or offspring care. Breeding individuals are also constrained to central place foraging within a limited range of the territory. For these reasons, many seabirds do not spend extensive periods or make regular visits to the colony following breeding failure. To investigate behaviour following breeding failure, we studied colony and nest attendance and daily number of visits for six Great Black-backed Gulls Larus marinus that had failed to breed following global positioning system (GPS) tag attachment on the northeast coast of Newfoundland, Canada. Three failed breeders reduced colony and nest attendance by an average 6.32 h/d (95% confidence interval: 1.14) after the estimated date of failure. Conversely, three other failed breeders showed no decrease in attendance, and one individual increased colony attendance by 5.4 h/d. We predicted that failed breeders would be more likely to forage while attending the colony relative to active breeders (i.e., incubating or chick-rearing) due to their lack of offspring and territory to defend. During 18 two-hour nest watches of active and failed breeders, active breeders (n = 4) behaved more aggressively (e.g., predation, swooping) toward gulls at nearby sites in the colony, while failed breeders (n = 6) behaved mostly passively (e.g., preening, sitting, P = 0.029). Our findings indicate that failed breeders continue to attend the colony after breeding failure, indicating potential benefits (e.g., maintaining breeding territory and pair bonding). Our findings also reveal that using tracking data to indicate breeding failure may be misleading and, thus, we suggest researchers also use visual confirmation of breeding failure, when possible, in future studies. Finally, we warn researchers of the negative effects of tag attachment on gull reproductive success
Demographics and Gross Pathology of Scoters and Scaups Killed by the \u3ci\u3eCosco Busan\u3c/i\u3e Oil Spill in California
No full textUnusual wildlife mortality events provide a unique opportunity to collect information on demographics, disease, and body condition in affected wildlife, which may be useful for informing oil spill damage assessments and future spill responses. In November 2007, the Cosco Busan Oil Spill occurred in San Francisco Bay, California, a globally important wintering area for waterfowl. The spill resulted in the mortality of scoters Melanitta spp. and scaups Aythya spp., species that have declined significantly over recent decades. We examined the demography (sex and age ratios) and prevalence of grossly apparent disease (acanthocephalan parasite infection and mycotic disease) in 288 Surf Scoters M. perspicillata, White-winged Scoters M. deglandi, Greater Scaup A. marila, and Lesser Scaup A. affinis killed in the oil spill. The proportions of females and juveniles in examined Surf Scoters was unexpectedly high (0.98:1, females:males, 0.73:1 juveniles:adults) for this species with normally strong male- and adult-biased populations. This disproportionate mortality of female Surf Scoters could result in a greater population impact on this female-limited species, suggesting a mechanism for steep declines in San Francisco Bay scoter numbers in the years after the Cosco Busan oil spill. Significantly greater rates of acanthocephalan infection in juvenile vs. adult Surf Scoters indicated a possible interaction between acanthocephalan parasitism and juvenile-biased mortality in our sample. Birds that died during rehabilitation had significantly greater rates of mycotic disease (10% infected) than birds found dead in the field (3%), indicating that infections began or worsened during rehabilitation. Greater Scaup had proportionally greater rates of infection with mycotic disease (26% of individuals) than other species, indicating that they may be particularly susceptible to the disease. We encourage the documentation of demographics and disease as a regular part of future responses to oil spills, or other mortality events, to gain insight into population impacts and improve rehabilitation efforts of affected populations
Diet Composition of Adelie Penguins \u3ci\u3ePygoscelis adeliae\u3c/i\u3e at Hope/Esperanza Bay during 2014-2019
No full textIn this study, we obtained samples through stomach lavage to determine the diet of Adelie Penguins Pygoscelis adeliae during the guard and crèche periods at Hope/Esperanza Bay, Antarctica, during four breeding seasons (2014–2019, except 2016). Antarctic krill was the dominant prey, contributing \u3e 99.6% of the diet by mass. The remainder of prey were fish, amphipods, and mollusks. Among fish, the nototheniid Pleuragramma antarcticum was the most frequent while the bathydraconid Parachaenichthys charcoti dominated by mass. Mollusks and fish increased their contribution during the crèche period in accord with seasonal patterns elsewhere
Impacts of Depredation by Large-billed Crows \u3ci\u3eCorvus macrorhynchos\u3c/i\u3e on the Colony of Japanese Murrelets \u3ci\u3eSynthliboramphus wumizusume\u3c/i\u3e at Eboshijima, Japan
No full textEboshijima, Japan is a small island in the Tsushima Strait that hosts a small colony of Japanese Murrelet Synthliboramphus wumizusume, an endangered seabird that breeds in the warm Kuroshio Current region around Japan and South Korea. We conducted a study to investigate the effects of depredation by Large-billed Crows Corvus macrorhynchos on murrelets after discovering 29 carcasses and 50 eggshells depredated by crows in four survey plots at Eboshijima in 2022. Trail cameras captured crows during daylight hours from 06h59 to 16h45. To estimate the existing population of Japanese Murrelet and predict scenarios that demonstrate the effects of corvid depredation on the murrelet population, we used a return-time (RET) capture-mark-recapture model. We evaluated the murrelet population using the best-fitting RET model and the capture histories of 187 murrelets mist-netted on Eboshijima during 2013–2022. We then simulated 1 000 iterations of a 50-year population using scenarios based on the parameters obtained from the best-fitting model. Our simulations indicate that corvid depredation could lead to the extirpation of the murrelet population, with no individuals remaining within 17 years. However, by reducing the corvid depredation effect by 50%, the probability of extinction can be lowered to less than 50% over the next 50 years. Therefore, we recommend implementing a crow translocation or removal program to protect the Eboshijima murrelet population. Additionally, further research should be conducted to identify breeding and non-breeding individuals, as well as active nesting sites
Predator Disturbance Contributed to Common Murre \u3ci\u3eUria aalge\u3c/i\u3e breeding failures in Cook Inlet, Alaska following the 2014–2016 Pacific Marine Heatwave
No full textThe 2014–2016 Pacific marine heatwave caused unprecedented die-offs and multi-year reproductive failures for Common Murres Uria aalge along the west coast of North America. Lingering impacts, such as declines in colony attendance and productivity, have persisted at some colonies following the heatwave and are attributed largely to changes in prey availability and quality. Here, we present evidence of an additional, top-down mechanism contributing to Common Murre breeding failures on Gull Island (Alaska): disturbance of nesting birds by aerial predators and associated egg depredation. We collected time-lapse images over five murre breeding seasons (2016–2020) on Gull Island to document the frequency, duration, and intensity of disturbances caused by aerial predators, as well as to quantify disturbance-associated egg depredation. To identify seasonal and inter-annual variability of disturbances, we calculated a daily disturbance index and compared years using generalized additive models. In all years, Bald Eagles Haliaeetus leucocephalus were the primary cause of disturbance, which led to periods of prolonged colony abandonment by murres and facilitated high levels of murre egg depredation by Glaucous-winged Gulls Larus glaucescens and Herring Gulls L. argentatus. We found that the seasonality of disturbance was an important factor in determining egg depredation rates. In years when disturbance levels were high and persisted later in the season, the colony experienced complete breeding failures due to disturbance-associated egg depredation. Our study revealed that the response of nesting murres to a strong environmental perturbation, such as the Pacific marine heatwave, can be complex and involve multiple stressors from both bottom-up and top-down factors
Relative Abundance, Seasonal Occurrence, and Distribution of Marine Birds in the Northern Gulf of Mexico
No full textMarine birds in the U.S. Gulf of Mexico have long been poorly studied. Given statutory obligations to protect migratory birds and endangered species, three broad-scale vessel and aerial programs initiated since 2010 have now surveyed the entire northern Gulf. Vessel coverage alone exceeds 700 d and 74,000 km of observer effort using 300-m strip transects. We supplemented these survey data with earlier, smaller-scale studies, eBird checklists, literature reviews, and other less accessible sources to create snapshot summaries of relative abundance, seasonal occurrence, and regional distribution for 117 taxa of marine and water birds reported from the northern Gulf (113 of which were substantiated with physical evidence). Using taxonomic and functional criteria, we identified 56 taxa characteristic of open shelf, slope, and pelagic waters (federal jurisdiction), 41 taxa with primarily coastal affinities (state and federal jurisdiction), and 20 taxa of sea and diving ducks. High species richness of marine birds in the northern Gulf is attributed to (1) a temperate-to-tropical gradient facilitating diverse marine environments year-round; (2) varied geographic origins of marine bird species using the Gulf; and (3) a mostly enclosed sea basin acting as a vagrant trap for wide-ranging species. Our taxonomic list and status updates seek to bridge information gaps for marine birds now subject to accelerated commercial uses of this region\u27s continental shelf, including newly proposed offshore wind energy development. Other applications include guiding risk and vulnerability assessments of Gulf marine birds, providing core content for seabird observer training, and prioritizing environmental impact reviews and monitoring programs in offshore energy construction and operations plans
Technological Evolution Generates New Answers and New Ways Forward: A Progress Report from the First Decade at the Karlsö Auk Lab
No full textIn 2008, we built an artificial nesting construction for Common Murres Uria aalge, the Karlsö Auk Lab, on an island in the Baltic Sea (Hentati-Sundberg et al., 2012). The aim was to create an environment in which the birds could be readily monitored and accessed, and technological equipment easily installed. In this current paper, we report on murre recruitment to the Auk Lab over the first decade, assess the performance of the birds living on the lab compared to natural cliff ledges, and revisit the original research questions. We conclude that the tremendous developments in sensor technology (video surveillance, automated scales, thermal cameras, weather sensors) and artificial intelligence was not anticipated 10 years ago. Several major scientific insights, including the effects of eagle disturbances and heat stress on the murres, have come as surprises and have been driven mainly by technology\u27s potential to deliver data with a resolution unattainable using traditional field studies. The dramatic increase in data volumes has partly been paired by automated analysis methods, but some aspects of the new technology, notably individual identification, have been more difficult than anticipated. The investment costs for information technology infrastructure, data storage, and processing capacity have also been substantial. We finish the paper by sketching out new research questions that will guide the next decade at the Auk Lab and repeating an invitation for research collaborations beyond our planned research focus
Causes and effects of science tutor attrition at the colleges of education in the northern zone of Ghana: A qualitative study
No full textThe study investigated the causes and effects of science tutor attrition in the colleges of education in the Northern Zone of Ghana. Three science and mathematics colleges were used for the study. The study adopted a qualitative approach with 9 participants who volunteered to take part. The interview guide was the sole instrument for data collection. The interviews were conducted through face-to-face and phone calls. The recorded conversations were transcribed and categorized into themes. The study found that the science tutor attrition rate was caused by several factors. These factors could be grouped into unmet expectations of the tutors and the general working environment of the colleges. Regarding the effects of attrition, the study found that it has led to overburdening tutors and, consequently, poor quality training of pre-service teachers. The reputation of the affected colleges is also affected. In view of these, the science tutors at the colleges of education are ready to exit for better conditions elsewhere. The study recommended that the staff of the college of education should be given remuneration that is comparable to what is given to the academic staff of other tertiary institutions with equivalent qualifications and ranks. Also, the working environment in the colleges must be tutor-friendly to avoid the frustrations and dissatisfaction expressed by participants
Bayes in the Brain: A review of \u3cem\u3eEverything is Predictable: How Bayesian Statistics Explain Our World\u3c/em\u3e, (2024) by Tom Chivers.
No full textTom Chivers’ Everything is Predictable: How Bayesian Statistics Explain Our World, is an interesting and wide-ranging narrative on Bayesian thinking, its history, and its applicability to both our everyday lives and the pursuit of scientific truth. Although appropriate for the non-expert, afficionados and teachers of quantitative literacy should find the plethora of examples, links to psychology as it applies to how people reason about probabilities, and even Chivers’ philosophical musings informative and thought-provoking