Author (Your Name)

Paul J. DoughertyFollow

Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Biology Dept.


Herb Wilson


Historic Christmas Bird Count and eBird data indicate that during winter invasions, North American irruptive fringillid species occur in relatively even numbers across latitudes east of the Rocky Mountains. Most boreal breeding species show large southward invasions every other winter, with this pattern typically being strongest across the northern and mid United States. eBird data confirms that many northern fringillids irrupt synchronously, and both datasets also show positive correlations between the winter movements of southern breeding species in many areas. Winter abundance records show negative correlations between northern breeding species and southern breeding species in nearly all monitored areas of North America.


Irruptions, Migration, Finches, Masting Cycles, Citizen Science

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Ornithology Commons