Avian influenza is a viral disease that can infect wild and domestic birds.In 2006,the United States Departments of Agriculture and Interior designed a large-scale,interagency surveillance effort that sought to determine if highly pathogenic avian influenza viruses were present in United States wild bird populations.This program,combined with the Canadian and Mexican surveillance programs,represented the largest,coordinated wildlife disease surveillance program ever implemented.We present data from 197,885 samples that were collected from over 200 wild bird species.While the initial impetus for surveillance focused on highly pathogenic avian influenza,the scale of the data provided unprecedented information on the ecology of avian influenza viruses in the USA,avian influenza virus host associations,and prevalence in matrix positive birds over time.Ultimately,significant advances in our knowledge of avian influenza will depend on both large scale surveillance efforts and on focused research studies.