The author is happy to make this file available for non-profit use, provided that direct acknowledgement is made any publication that uses this work.
Warning! Updated versions of this file will be provided on request whenever the AOU Check-List changes or new exotic or accidental species are added, and the phylogenetic keys will change in each version. It would be wise to structure any applications that use phylogenetic sorting so that they always extract the latest keys from the file just before sorting, rather than carrying around copies of the keys in other files. The author is available to assist in implementation of systems that gracefully survive the continued flux in avian taxonomy.
Refer to the history of AOU numbers for an example illustrating why it is a bad idea to try to use a static numeric taxonomic code.