The North American Bird Phenology Program, part of the USA-National Phenology Network, was a network of volunteer observers who recorded information on first arrival dates, maximum abundance, and departure dates of migratory birds across North America. Active between 1880 and 1970, the program was coordinated by the Federal government and sponsored by the American Ornithologists' Union. It exists now as a historic collection of six million migration card observations, illuminating almost a century of migration patterns and population status of birds. Today, in an innovative project to curate the data and make them publically available, the records are being scanned and placed on the internet, where volunteers worldwide transcribe these records and add them into a database for analysis.