General map illustrating previous reports of finch trichomonosis in France and detailed map of northern France illustrating the geographical origins of the data about dead and diseased birds. (A) Administrative départements with confirmed and suspected events of finch trichomonosis in dark and light grey, respectively; Départements in blue represent the northern France area and contains the studied sites; Years of the events are written for each département, years with a slash represent winter event. (B) The circle broadly defines the Boulonnais region. Red dots represent bird ringing stations within the Boulonnais where dead and diseased birds where observed and recorded over the first trimester of 2017 with 1: Bournonville, 2: Wirwignes, 3: Tingry and 4: Parenty; Green dots represent additional locations where dead birds were retrieved with 5: Herbinghen, 6: Bezinghem, 7: Preures, 8: Enquin-sur-Baillons in the Boulonnais, and 9: Vimy, 10: Arras, 11: Achicourt and 12: Saint-Aybert in the inland area.