Migrating birds are potentially exposed to hundreds if not thousands of toxic chemicals released from urban, agricultural and industrial uses over a broad geographic range. The ability for a bird to effectively judge when to depart, successfully navigate the route, and endure the flight distance are all vital to ensure survival but are also known to directly impact reproductive performance. While largely overlooked, there is evidence of connection between several classes of environmental contaminants and impaired migratory ability of birds.
THREATS TO MIGRATORY SHOREBIRDS AT STOPOVER SITES IN THE CENTRAL FLYWAY
Shorebirds are known for their impressive long-distance flights. They migrate from winter grounds in the United States, Central, and South America to their breeding areas in the northern latitudes. During the annual cycle, they face numerous potential risks. We are interested in understanding whether environmental contaminants such as PAHs and other dioxin-like compounds may be playing a role in declines of migrant shorebirds, particularly in the more poorly studied Central Flyway.
Migratory shorebird populations have declined by almost half since 1970, experiencing some of the most substantial declines of any guild. Among threats affecting their survival, environmental pollution may be playing an important role since large numbers of birds aggregate in focal wintering and stopover sites along the migratory path. The large number of potential wintering areas, variation in pollution levels and the lack of information about shorebird migration ecology and connectivity make it difficult to establish where and when problems are occurring.
We have research projects which aim to:
understand the extent to which shorebirds are exposed to polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), and dioxins across their range in North and South America
evaluate the toxicity to Sanderlings, a model long distance migratory shorebird, and other bird models in vitro and in vivo
evaluate fuelling ability, migration routes and stopover timing in relation to stopover site quality and contaminant levels
CHEMICAL EFFECTS ON MIGRATORY PHYSIOLOGY AND COGNITION
New ecotoxicological research is evaluating how exposure to these chemicals can lead to lasting sublethal impacts related to migration. Since migration in birds typically involves 3 major stages: the pre-migratory period, flight period and landing/recovery, our research is exploring the potential mechanisms for various contaminant groups (endocrine disruptors, aryl hydrocarbon receptor agonists, and neurotoxic insecticides) to affect birds’ ability to initiate and complete these migration stages.
We are conducting studies of migratory behaviour including orientation, activity, cognition and learning in response to neurotoxicant exposure. This work involves several studies including:
1) understanding how the brain of European starlings changes in response to migration cues and contaminant exposure during key life stages (Flahr et al. 2015 ES&T)
2) testing the latent behavioural and cognitive effects of early developmental exposure of European starlings to Aroclor 1254 (a known thyroid hormone disruptor) using Emlen funnel trials (Flahr et al. 2015 ES&T) and modified radial arm mazes (Zahara et al. 2015 ET&C)
3) comparing the short term neurotoxic responses of insecticides (imidacloprid and chlorpyrifos) in captive and free living songbirds (Dr. Maragaret Eng in collaboration with Bridget Stutchbury at York University) (Eng et al. 2017 Sci Reports)