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9 January, 2025

By Alexandre Terrigeol

This article is a summary of the paper by Jake Walker and colleagues, published in the journal Ornithological Applications in December 2024.

Rusty Blackbird, what is its status?

Rusty Blackbird has experienced a significant population decline over the past century. Between 1970 and 2010, its population is believed to have dropped by nearly 90%. Habitat loss, particularly of forested wetlands at its wintering and migratory stopover sites, appears to be one of the main factors contributing to this decline.

Long considered a nuisance species, similar to other blackbirds, it has also been one of the collateral victims of lethal control programs aimed at reducing nuisances, health risks, and crop damage.

Pictured, an individual in breeding plumage.

How to track a species?

The Tadoussac Bird Observatory, which has been conducting migration monitoring projects for over 30 years, launched specific tracking projects using nano-transmitters in 2014. Since then, these projects, including this recent article, have resulted in scientific publications aimed at enhancing our knowledge of birds in Quebec.

From 2017 to 2020, nearly sixty individuals were fitted with transmitters at the dunes of Tadoussac. From September to November, hundreds of individuals are observed migrating at this site every year. In addition to visual surveys, targeted projects on several bird species, for which we lack information on their migration strategies, are carried out annually.

More individuals were also captured in New England between 2019 and 2023 to better understand their wintering areas, migratory stopovers, and migration routes in the eastern part of North America. These data are crucial for guiding conservation strategies for the species.

Promising results!

Thanks to the transmitters, detected by the Motus network towers, a large amount of data has been collected. The analyses revealed the existence of vital migratory stopover sites, such as the Chesapeake and Delaware Bays, where large concentrations of Rusty Blackbirds pause during their migrations.

The St. Lawrence Plain and the New England coast also play a crucial role in their migratory journey, providing essential resting and refueling spaces.

Pictured, an individual in non-breeding plumage, with its characteristic “rusty” color. You can also observe its nictitating membrane, an additional transparent eyelid that protects its eyes, moistens them, and allows for some visibility.

Considering different populations for better conservation

The study also highlighted notable differences in the migration strategies of two populations. Birds from Quebec spend more time at their migratory stopover sites, while those from New England extend their stay at their breeding grounds.

This suggests that birds from Quebec rely more heavily on these stopover sites and wintering habitats, which could make them more vulnerable in the context of the decline of these environments.

Pictured, a typical habitat of the Rusty Blackbird, found in Quebec, particularly on the North Shore.

An Issue of Habitat

The protection of this species therefore relies on effective habitat management along its migratory corridor. Although complex, this approach is crucial for helping the Rusty Blackbird. Additionally, by further expanding the Motus network across North America, other migratory stopovers and essential sites could be identified, thereby offering new opportunities for the species’ conservation.

To read the article: Walker, J., Bégin-Marchand, C., Terrigeol, A., Therrien, J. F., Côté, P., Burford, L., Foss, C. R., & Tremblay, J. A. 2024. Euphagus carolinus (Rusty Blackbird) from two different breeding populations in northeastern North America exhibit chain migration yet use the same region for stopover. Ornithological Applications, duae066. (Download)