Intraclutch variation of egg size in insects (Genavieve Desjardin, MSc)
Developmental trajectories and post-fledging performance (Joshua Allen, PhD)
Diluted bitumen toxicity and environmental monitoring for spill preparedness (Mason King, Post-doc)
Individual variation, plasticity, and co-variation of egg size in the European starling (Raven Barbera, MSc)
Effects of diluted bitumen on flight and diving behaviour of Rhinoceros Auklets (Catherine Lee-Zuck, MSc)
Mitigating costs of increased workload during reproduction (Brett Hodinka, PhD)
Anthropogenic impacts on a seabird in the Salish Sea ecosystem (Hannah Hall, ECCC collaborator)
Intraclutch variation of egg size in insects
Individual quality (variable and correlated with fitness) is determined by phenotypic (e.g., body size) or life-history traits (eg. fecundity). Although many studies have focused on phenology and fecundity, few studies have researched the causes and consequences of intraspecific variation of egg size. Fewer studies have considered the impact of warming temperatures due to climate change on ectotherms and their future fecundity. My research explores individual quality in Harmonia axyridis, the Asian ladybird beetle, a globally introduced predatory generalist, without post-hatching care. This project will include a literature review of egg size across insect taxa and a lab component to manipulate individual quality under increase temperature. Our findings for individual egg size variability will provide base knowledge that can project population trends under warming temperatures. Further, it will contribute to a better understanding of the trade-offs and the mechanisms behind egg size variation within a species.
Developmental trajectories and post-fledging performance
​Developmental maturity at fledging has been used to explain variation in post-fledging mortality across avian taxa, yet our ability to predict individual variation in post-fledging performance is limited. Metrics of fledgling condition are typically restricted to measures of body size, some of which are highly plastic whilst others are developmentally hard-wired, influencing the efficacy of somatic traits as fitness biomarkers. Investigating the relationship between these traits and physiological condition may drastically improve our understanding of the high rates of juvenile mortality in many species, but little is known of nestling physiology in the approach to fledging. My research examines somatic and physiological traits in developing European starlings (Sturnus vulgaris) to provide a more robust metric of fledgling condition which may better predict post-fledging performance. By experimentally manipulating nestling development (e.g., weighted backpacks), fitting cameras in the nest and utilizing automated radiotelemetry, I aim to test the developmental plasticity, interactions among, and final maturity of fledgling somatic and physiological traits, the putative role exercise-like behaviors (e.g., wing-flapping) play during development, and their consequences for life after fledgling.
Diluted bitumen toxicity and environmental monitoring for spill preparedness
Petroleum industry initiatives to intensify overseas export would increase the likelihood of spills that can be catastrophic for marine birds, yet the effects on birds of bituminous petroleum that Canada currently produces at more than twice the volume of conventional crude remain untested. We are currently completing investigations to elucidate the toxic effects of bituminous petroleum on birds. These investigations include diluted bitumen exposure studies in embryos and zebra finches, monitoring to establish baseline oil contamination in a surrogate sentinel species: inter-tidal mussels, and assessing existing persistent pollutant burdens in marine birds, and their effects, which oil pollution could add to. This research will yield vital knowledge of the potential effects of an understudied, broadly transported petroleum product’s toxicity to vulnerable wildlife taxa. This first phase of this project is available as a literature review of the effects of petroleum on birds.
Individual variation, plasticity, and co-variation of egg size in the European starling
​Avian egg mass varies markedly within populations, with the largest eggs measuring up to twice the size of the smallest, and ~70% of this variation is due to variation among individual females (Christians 2002). Many studies highlight the high repeatability of egg size, suggesting that this trait is relatively inflexible within individual female birds. In contrast, some studies continue to suggest that there can be substantial, “adaptive” plasticity in egg investment. If egg size is a phenotypically plastic life-history trait, we predict that it would show potentially adaptive variation in different ecological contexts (e.g. seasonally, yearly). Using data from a long-term study of European starlings (Sturnus vulgaris, 2002-2022), my research will a) analyse individual variation in egg size, focusing on phenotypic plasticity and b) analyse covariation between egg size, life-history traits, lifetime productivity, and survival. By understanding how egg size correlates with fitness and individual quality, this trait can be included in the suite of traits used to predict reproductive success.
Effects of diluted bitumen on flight and diving behaviour of Rhinoceros Auklets
Although it is well known that oil spills pose a threat to marine birds, there is a lack of understanding about the risks posed by new, unconventional crudes, e.g. diluted bitumen compared to conventional petroleum products. While the dramatic impacts of large-scale oil spills to marine wildlife are well known, far less far less is understood about sublethal effects of petroleum when birds are exposed to smaller amounts of oil. My research looks at the effects of internal and external exposure to small amounts of diluted bitumen on breeding Rhinoceros Auklets (Cerorhinca monocerata) on Middleton Island, Alaska. Attaching GPS-depth loggers and tri-axial accelerometers to free-living animals will enable a high-resolution investigation into how behaviours, such as flying and diving, are acutely affected by exposure to this contaminant. Monitoring their breeding success will determine how a wild bird may be expected to act following an acute exposure.
Mitigating costs of increased workload during reproduction
It has long been assumed that many activities of free-living animals are energetically demanding or “hard work”, for example, avian migration. If animals are working hard, especially during reproduction, it is likely they might pay a cost of increased workload: a “cost of reproduction” - that is, the idea that individuals can maximize lifetime reproductive success only by increasing workload to allocate resources to current offspring against the production of future offspring and self-maintenance. Nonetheless, over the past 50 years, studies of the trade-off between parental effort and survival have provided equivocal evidence, especially in female birds, with many failing to find any support while others find evidence against it. Therefore, if parental care is so costly, why is it so difficult to demonstrate negative (e.g., physiological) effects of the intense activity associated with chick-rearing? In an experimental approach using weighted backpacks to artificially increase workload, tri-axial accelerometers and GPS units to track daily movement and daily energy expenditure, and an automated nest box weighing system to collect fine-scale mass data, the goal of my PhD research is to investigate several physiological and behavioral mechanisms birds may employ to attenuate the costs increased workload associated with reproduction. For additional information on this work, check out Brett’s personal webpage.
Anthropogenic impacts on a seabird in the Salish Sea ecosystem
Seabirds are useful biomonitors of marine environments, which are increasingly impacted by anthropogenic activity. This is especially true in the Salish Sea, Pacific Northwest, but this area remains highly biologically productive providing year-round habitat for marine top-predators, including Glaucous-winged gulls (GWGU; Larus glaucescens). In recent decades, GWGU populations have declined in the Salish Sea concurrent with a dietary shift to more terrestrial prey. In collaboration with Environment and Climate Change Canada, we are investigating the wintering habitat use and contaminant exposure of GWGU throughout the Salish Sea. By evaluating the relationships between diet, contaminant burdens, and physiological health of GWGUs, as well as habitat use determined using GPS tags, we aim to better understand the impacts of anthropogenic activities on the health of GWGUs and the Salish Sea Ecosystem more generally.
Photo used under Creative Commons from jinkemoole