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Results from Bobolink Migration and Wintering Ecology Research


For a decade VCE has shed illuminating light on Bobolink migration and wintering ecology. Our research has revealed where Bobolinks go after they leave their breeding grounds, the habitats they use, the food they eat, and the threats they encounter. Guided by these findings, VCE is informing effective full life-cycle conservation, addressing the most pressing threats, and forging new partnerships.

Bobolink Migration Patterns and Wintering Sites


Bobolinks breeding in Oregon, Nebraska, and Vermont all converge into 3-6 week stops (brown) and 3-4 month wintering areas (blue) in South America.

Bobolinks can be found in North America from Oregon to Maine, and from British Colombia to Nova Scotia. Do populations that breed in such disparate regions also migrate and winter in different places? Using light-level geolocators, VCE and collaborators found that Bobolinks from across the breeding range— Oregon, Nebraska, and Vermont—all converge in time and space in South America. Nearly the entire population funnels through the Llanos grasslands of Venezuela and then the lowlands of eastern Bolivia.

This geolocator research provides critical knowledge for full life cycle conservation. We now know where to focus conservation action, who to partner with, and can assess threats to Bobolinks during the non-breeding season. The geolocators revealed much more about Bobolink migration (see link below), and this work continues across the Bobolink range in Canada.

Renfrew, R. B., D. Kim, N. Perlut, J. Fox, J. Smith, and P. P. Marra. 2013. Phenological matching across hemispheres in a long-distance migratory bird. Diversity and Distributions 19:1008–1019. (Abstract)


A nerve-disrupting, highly toxic organophosphate called monocrotophos is widely used on crops in many South American countries. VCE documented exposure of Bobolinks to this insecticide at lethal and sublethal levels in Bolivian rice fields. Using our findings, we facilitated discussions between toxicologists and Bolivia’s industry, governmental, and NGO leaders to explore ways to rid the country of the problem pesticide. The Bolivian government, also concerned with the ill effects of monocrotophos on farmworkers, responded swiftly and banned it for use on these crops. We continue to explore the use and effects of pesticides in other countries where Bobolinks feed in agricultural fields.

Blood Parasites

Each year a few dozen Bobolinks pass through the Galapagos in the fall, apart from where the bulk of the Bobolink population migrates. We provide blood samples to our collaborators at Louisiana State University who are studying Bobolinks as the source of two types of avian malaria that infect Galapagos birds.

Peer-reviewed journal papers