To gain insight into the migrations of purple finches, Leslie Brainerd Arey Professor of Biosciences Herb Wilson analyzed all the banding data on purple finches from the Bird Banding Laboratory from 1921 until 2008, with particular interest in answering three questions: During irruptions do birds from one area, such as New England, move straight south, or do they spread across the continent? Do purple finches show fidelity to breeding sites? Do they show fidelity to wintering sites?