Data retrieved from the interactive site should be cited as:
USGS Patuxent Wildlife Research Center. 2014. North American Breeding Bird Survey Internet data set, 21 April 2014 (http://www.pwrc.usgs.gov/bbs/retrieval/).

Data retrieved from the ftp site should be cited as:
USGS Patuxent Wildlife Research Center. 2014. North American Breeding Bird Survey ftp data set, version 2014.0 (ftp://ftpext.usgs.gov/pub/er/md/laurel/BBS/datafiles/).

Acknowledgments:
These data are the result of efforts by thousands of U.S. and Canadian BBS participants in the field, as well as, USGS and CWS researchers and managers. All publications based on these data should acknowledge all of these efforts. In addition, if a publication is based solely on the analysis of BBS data, we suggest that you involve the BBS office with the writing and/or review of the manuscript. We would also appreciate receiving a reprint or photocopy of any such article at the time of its publication.