Of all aspects of the Rusty Blackbird life cycle, we know the least about migration. Research during the last several years has greatly increased our understanding of this species’ breeding and wintering biology, but as with many migratory birds, our understanding of Rusty Blackbird migratory ecology lags behind. However, recent studies using sophisticated technologies like geolocators and feather isotope analysis have shed some light on Rusty Blackbird migration pathways and timing (Hobson et al. 2010, Johnson et al. 2012).Rusties depart from northern forests to begin their rather leisurely southward migration sometime in early to mid-September. They spend about one month resting and feeding at stopover sites between mid-October and mid-November, and they arrive on southeastern wintering grounds in late November. Including stopover time, autumn migration lasts 10-12 weeks. In spring, the impending breeding season urges the northward migration to progress much more quickly. Most birds leave the wintering areas in late March or early April and arrive on the breeding grounds a mere 2-4 weeks later.
Scientists have also been able to identify at least two distinct migratory pathways used by Rusty Blackbirds – an eastern Atlantic flyway, a Mississippi flyway, and possibly a Central flyway as well. The Appalachian Mountains appear to be an important feature dividing Rusty Blackbird populations during migration and over winter, as few birds cross the mountain range.
Despite these important insights, we still have a long way to go towards understanding Rusty Blackbird migration. What specific routes do they travel, and do these pathways differ from year to year? What habitats do they use along their journey, and where are their major stopover locations? The answers to these questions will be critical to advance Rusty Blackbird conservation. To this end, the IRBWG is initiating a Rusty Blackbird Migration Blitz in the spring of 2014. All birders are encouraged to participate!
Hobson, K. A., Greenberg, R., Van Wilgenburg, S. L. and Mettke-Hofmann, C. (2010). Migratory connectivity in the Rusty Blackbird: Isotopic evidence from feathers of historical and contemporary specimens. Condor, 112(4): 778–788.
Johnson, J. A., Matsuoka, S. M., Tessler, D. F., Fox, J. W. and Greenberg, R. (2012). Identifying Migratory Pathways Used by Rusty Blackbirds Breeding in Southcentral Alaska. Wilson Journal of Ornithology, 124(4): 698–703.