Gregory J. Robertson

Environment Canada | EC · Wildlife Research Division

Highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b viruses were first detected in St. John’s, Canada in late 2021. To investigate the patterns of avian influenza virus (AIV) infection and immune responses subsequent to the arrival of H5N1, we sampled the wild urban duck population in this area for a period of 16 months after the start of...

In 2022, a severe outbreak of disease caused by 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...

Seabird colonies with long-term monitoring records, i.e., > 50 years, are rare. The population data for northern gannets (Morus bassanus) in Cape St. Mary’s (CSM) Ecological Reserve (Newfoundland and Labrador, Canada) is robust, extending back to 1883 when the colony was presumed established. We inferred the colony’s historical population shifts by...

Climate change poses a significant threat to Arctic ecosystems. Evaluation of genetic diversity within and differentiation among populations is needed to effectively conserve Arctic species and ensure genetic variation is appropriately managed. This research examined population genetic structure in Larus hyperboreus (Glaucous Gull), a circumpolar A...

The Government of Canada has committed to protect 10% of coastal and marine areas by 2020, which requires the creation of new protected areas throughout Canada’s marine territory. The Labrador Inuit Land Claims Agreement (LILCA), signed in 2005, established the Labrador Inuit Settlement Area (LISA) which includes 72,520 km2 of lands and 48,690 km2...

The Atlantic Puffin (Fratercula arctica; hereafter ‘puffin’) breeds at the southern limit of its range in the Gulf of Maine, where waters are warming faster than most of the world’s oceans. Puffin productivity and survival have decreased in the Gulf of Maine with warming, but population-level declines have not been detected. Understanding the conne...

Following the detection of novel highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b in Newfoundland, Canada, in late 2021, avian influenza virus (AIV) surveillance in wild birds was scaled up across Canada. Herein, we present the results of Canada’s Interagency Surveillance Program for Avian Influenza in Wild Birds during the first...

Migratory seabirds move across ocean basins and are one of the primary reservoirs of low pathogenic avian influenza virus (LPAIV). This includes the millions of thick-billed murres (Uria lomvia) and common murres (Uria aalge) that are distributed across northern hemisphere oceans. In response to increasingly frequent detections of highly pathogenic...

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 Apri...

How to manage harvest under great uncertainty is a fundamental question for many wildlife managers, particularly when resources necessary to estimate abundance or population trends are limited. The large Newfoundland and Labrador murre hunt is the only licensed harvest of seabirds in Canada. Though harvest of thickbilled murres (Uria lomvia) and co...

Highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b viruses were first detected in St. John’s, Newfoundland, Canada in late 2021, with the virus rapidly spreading across the western hemisphere over the next year. To investigate the patterns of avian influenza virus (AIV) infection and immune responses subsequent to the arrival of H5N1, we...

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. Mortali...

Following detection of novel highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b in Newfoundland, Canada in late 2021, avian influenza surveillance in wild birds was scaled-up across Canada. Herein, we present results of Canada's Interagency Surveillance Program for Avian Influenza in wild birds during the first year (November 2021...

The American Common Eider (Somateria mollisima dresseri) winters along the eastern coasts of the northern U.S. and southern Canada. Various lines of evidence indicate recent localized changes in eider abundance, particularly in the Gulf of Maine, where the most dramatic oceanic changes in the Northwest Atlantic are also underway. A range-wide overv...

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are h...

The effect of gull predation on sympatric seabirds has garnered much attention and management action in recent decades. In Witless Bay, Newfoundland, Canada, gulls depredate significant numbers of Leach’s Storm-petrels (Hydrobates leucorhous) annually. We quantified this predation on Gull Island in Witless Bay, and its effects on the storm-petrel p...

During multiple annual spawning runs from 2013 to 2021, over 9,000 mature anadromous alewife (Alosa pseudoharengus A. Wilson, 1811) were monitored with passive integrated transponders (PITs) in four rivers of the Chignecto Isthmus, Bay of Fundy, Canada. A subsample of 384 individuals tagged during 2016–2019 were aged from 3 to 6 years (mean ± SD; 4...

During 2021-22 High Pathogenicity Avian Influenza (HPAI) killed thousands of wild birds across Europe and North America, suggesting a change in infection dynamics and a shift to new hosts, including seabirds. Northern Gannets (Morus bassanus) appeared especially severely impacted, but limited understanding of how the virus spread across the metapop...

2023. Experts' opinions on threats to Leach's Storm-Petrels (Hydrobates leucorhous) across their global range. Avian Conservation and Ecology 18(1):11. https://doi. ABSTRACT. Seabirds are declining globally, though the threats they face differ among and within species and populations. Following substantial population declines at several breeding co...

The eastern population of harlequin duck Histrionicus histrionicus in Canada has been designated a species of special concern since 2001 and as endangered from 1991 to 2001, largely due to low and declining wintering numbers detected in the 1980s. Our objectives were to summarize the current state of knowledge of harlequin duck abundance and distri...

The common snipe (Gallinago gallinago) is a wader that breeds in subarctic regions from Iceland to Russia, and for which global populations are in decline. We studied snipe breeding in western Iceland between 1998 and 2020, locating nests and ringing birds annually. In 2019 and 2020, we deployed geolocators on nesting adults to estimate the timing...

Background Homeothermic marine animals in Polar Regions face an energetic bottleneck in winter. The challenges of short days and cold temperatures are exacerbated for flying seabirds with small body size and limited fat stores. We use biologging approaches to examine how habitat, weather, and moon illumination influence behaviour and energetics of...

Species and populations with greater cognitive performance are more successful at adapting to changing habitats. Accordingly, urban species and populations often outperform their rural counterparts on problem-solving tests. Paradoxically, urban foraging also might be detrimental to the development and integrity of animals' brains because anthropoge...

Conservation of mobile organisms is difficult in the absence of detailed information about movement and habitat use. While the miniaturization of tracking devices has eased the collection of such information, it remains logistically and financially difficult to track a wide range of species across a large geographic scale. Predictive distribution m...

Highly pathogenic avian influenza (HPAI) viruses of the A/Goose/Guangdong/1/1996 lineage (GsGd), which threaten the health of poultry, wildlife and humans, are spreading across Asia, Europe, Africa and North America but are currently absent from South America and Oceania. In December 2021, H5N1 HPAI viruses were detected in poultry and a free-livin...

Reproduction in procellariiform birds is characterized by a single egg clutch, slow development, a long breeding season and obligate biparental care. Female Leach’s Storm Petrels Hydrobates leucorhous, nearly monomorphic members of this order, produce eggs that are between 20 and 25% of adult body weight. We tested whether female foraging behaviour...

Bycatch in fisheries remains one of the biggest conservation threats to seabirds globally, but there has been limited attention given to bycatch in the Arctic. Here, we worked with Inuit commercial fishers in the Cambridge Bay region of Nunavut to record bycatch of birds, as part of a fish bycatch reporting initiative, in weir and gillnet fisheries...

Seabirds are important biovectors of contaminants, like mercury, moving them from marine to terrestrial environments around breeding colonies. This transfer of materials can have marked impacts on receiving environments and biota. Less is known about biotransport of contaminants by generalist seabirds that exploit anthropogenic wastes compared to o...

Seabird population size is intimately linked to the physical, chemical, and biological processes of the oceans. Yet, the overall effects of long‐term changes in ocean dynamics on seabird colonies are difficult to quantify. Here, we used dated lake sediments to reconstruct ~10,000‐years of seabird dynamics in the Northwest Atlantic to determine the...

Starvation is a ubiquitous process in nature as all animals depend on finite resources to survive. Limited food resources can lead to starvation-induced mortality and, depending on the scale of the limitation, population-level consequences may emerge. However, attempts to model starvation-induced mortality are rare as it is difficult to isolate the...

Oil spills most visibly affect waterbirds and often the number of birds affected, a key measure of environmental damage from an incident, is required for public communication, population management, and legal reasons. We review and outline steps that can be taken to improve accuracy in the estimation of the number of birds affected in each of three...

The addition of eggs to a nest by a conspecific is known for approximately 250 bird species. Understanding the evolution of conspecific brood parasitism (CBP) requires assessment of fitness consequences to the egg recipient (host). We addressed host traits and the effects of CBP on future reproduction (i.e., annual survival) and hatching success of...

Common eiders Somateria mollissima have been a focus of conservation and management efforts in eastern North American for over a century; however, the complex population structure and multiple subspecies make assessing the status of populations challenging. The coastlines of Nova Scotia, Canada, are an important wintering area for common eiders, an...

American black ducks, native to eastern North America, have been the focus of significant international conservation and management programs. The combined USA and Canadian population has traditionally been managed as a single population; however black duck demographics may vary by region. To help understand potential regional differences in black d...

Ingestion of plastic pollution by pelagic seabirds is well-documented globally, but increasingly, researchers are investigating plastic ingestion in generalist predators and scavengers like gulls. We studied the gut contents of two sympatric gull species, American herring gulls (Larus smithsoniansus) and great black-backed gulls (L. marinus), colle...

The lack of long-term monitoring data for many wildlife populations is a limiting factor in establishing meaningful and achievable conservation goals. Even for well-monitored species, time series are often very short relative to the timescales required to understand a population’s baseline conditions before the contemporary period of increased huma...

Performing microbiological assays on environmental samples in field settings poses several logistical challenges, including the availability of suitable field-based equipment and the timely arrival of samples to a testing laboratory. Due to the importance of assessing microbiological water quality, but with a lack of methodologies to perform these...

This study examines the occurrence and underlying factors of onshore strandings of two species of seabirds breeding in Newfoundland and Labrador, Canada. Atlantic Puffins (Fratercula arctica) are found stranded in coastal communities bordering the Witless Bay Ecological Reserve in artificially lit areas. Between 2011 and 2020, 3845 recently fledged...

After successful conservation and management efforts throughout much of the twentieth century that led to the recovery of common eiders (Somateria mollissima) breeding in several jurisdictions in eastern North America, their abundance has declined in recent years, probably linked to various environmental stressors. To evaluate where to focus future...

In the eastern North Atlantic, declines in the volume of Atlantic Puffin (Fratercula arctica (Linnaeus, 1758)) eggs have been associated with shifts in the marine ecosystem, such as changes in the abundance of forage fishes and increasing sea-surface temperatures. In the western North Atlantic, where similar shifts in oceanographic conditions and c...

Incidental mortality of marine birds in fisheries is an international conservation concern, including in Canada where globally significant populations of vulnerable diving species overlap with coastal gillnet fisheries. In British Columbia (BC), commercial salmon gillnet fishing effort was historically very high (>200,000 days fished annually in th...

Parvoviruses are small single-stranded DNA viruses that can infect both vertebrates and invertebrates. We report here the full characterization of novel viruses we identified in ducks, including two viral species within the subfamily Hamaparvovirinae (duck-associated chapparvovirus, DAC) and a novel species within the subfamily Densovirinae (duck-a...

Consuming omega-3 fatty acids (n3-LCPUFAs) during development improves cognition in mammals, but the effect remains untested in other taxa. In aquatic ecosystems, n3-LCPUFAs are produced by phytoplankton and bioaccumulate in the food web. Alarmingly, the warming and acidification of aquatic systems caused by climate change impair n3-LCPUFA producti...

https://arctox.cnrs.fr/en/home/ Mercury (Hg) is a natural trace element found in high concentrations in top predators, including Arctic seabirds. Most current knowledge about Hg concentrations in Arctic seabirds relates to exposure during the summer breeding period when researchers can easily access seabirds at colonies. However, the few studies f...

Significance Globally, seabird populations are in decline. Without long-term monitoring, realistic conservation goals are difficult to establish. Here, we use lake sediment records to reconstruct the long-term dynamics of an important colony of Leach’s Storm-petrels. We show that this seabird population underwent moderate natural population fluctua...

Seabirds that form large colonies often act as biovectors that transport and concentrate large amounts of nutrients, metals, and contaminants from marine feeding areas to inland breeding grounds. This enrichment can potentially transform and structure primary productivity, vegetation communities, and species richness. In a previous paleolimnologica...

Highly migratory species pose unique conservation and management challenges, especially when significant mortality occurs away from breeding concentrations. Population genetics and genomics may help with the appropriate management of these species by (1) determining the population genetic structure of a species across its range, and (2) allowing th...

Performing microbiological assays on environmental samples in field settings poses logistical challenges with respect to the availability of suitable equipment or the ability to get samples to the laboratory in a timely fashion. For example, the viability of some bacteria can decrease greatly between sampling and arrival to the laboratory for proce...

Many seabird species in the North Atlantic region have shown considerable declines in their populations during recent decades. One such species is the Arctic tern (Sterna paradisaea), a small seabird which migrates farther than any other seabird each year and whose global population is thought to be in decline. We used banding data of chicks and ad...

In this investigation, we used a combination of field- and laboratory-based approaches to assess if influenza A viruses (IAVs) shed by ducks could remain viable for extended periods in surface water within three wetland complexes of North America. In a field experiment, replicate filtered surface water samples inoculated with duck swabs were tested...

The black-legged kittiwake (Rissa tridactyla, hereafter kittiwake) is a small pelagic seabird and is the most numerous gull species in the world. It has a circumpolar distribution, and breeds in the arctic and boreal zones of the Northern Hemisphere. It’s breeding distribution is widespread and ranges across the North Atlantic from the west coast t...

Background: Recent studies have proposed that birds migrating short distances migrate at an overall slower pace, minimizing energy expenditure, while birds migrating long distances minimize time spent on migration to cope with seasonal changes in environmental conditions. Methods: We evaluated variability in the migration strategies of Herring G...

Sympatric communities of organisms may exploit different ecological niches to avoid intra- and interspecific competition. We examined the isotopic niches of American black ducks (Anas rubripes) and mallards (A. platyrhynchos) wintering in coastal and urban areas of Atlantic Canada and compared isotopic niche with digestive tract morphologies and bl...

Scientists across many fields are faced with the challenge of synthesizing and communicating information from large and complex data sets. The field of stock assessment is no exception as the volume and variety of the data has grown alongside the computational methods used to integrate them. While this growth in data and model complexity has improv...

Populations often show complex spatial and temporal dynamics, creating challenges in designing and implementing effective surveys. Inappropriate sampling designs can potentially lead to both under-sampling (reducing precision) and over-sampling (through the extensive and potentially expensive sampling of correlated metrics). These issues can be dif...