The author checked the six-letter system for collisions by writing a computer program that applies the rules mechanically to each name, and then running the program on a file of all the species names from the current AOU Check-List.
Only nine two-way collisions were found. There were no three-way collisions. Here is a list of the collisions and their resolutions. For safety's sake, both species involved in a collision are given substitute codes.
Wrong Right Name ------ ------ ---- BAROWL BRDOWL Barred Owl BRNOWL Barn Owl BLAWAR BKBWAR Blackburnian Warbler BKPWAR Blackpoll Warbler BLUGRO BLUGRB Blue Grosbeak BLUGRS Blue Grouse BRSPET BRIPET British Storm-Petrel BARPET Band-rumped Storm-Petrel BTGWAR BTNWAR Black-throated Green Warbler BTYWAR Black-throated Gray Warbler GOCWAR GCHWAR Golden-cheeked Warbler GCRWAR Golden-crowned Warbler LESPET LCSPET Leach's Storm-Petrel LSSPET Least Storm-Petrel RUTHUM RTHHUM Ruby-throated Hummingbird RTLHUM Rufous-tailed Hummingbird SPOSAN SPBSAN Spoonbill Sandpiper SPTSAN Spotted Sandpiper
Using the six-letter system with names other than standard species names leads to more collisions. Some involve obsolete names, or forms that have never been accepted on the standard checklists. These are included to allow handling of older names and names from rejected or hypothetical records.
Here is the list of all the additional collisions encountered after using this code system for over ten years of work with CBC and other field records of all kinds.
Wrong: Right: ------ ------ BELSPA BLDSPA "Belding's" (Savannah) Sparrow BLLSPA "Bell's" (Sage) Sparrow BUFBOO MASBOO "Blue-faced" [=Masked] Booby BFOBOO Blue-footed Booby CATHAR CATHAC Catharacta sp. CATHUS Catharus sp. COLUMB COLBA Columba sp. COLBID columbid sp. COLBIN Columbina sp. DENDRO DENCYG Dendrocygna sp. DENICA Dendroica sp. FRINGI FRINLA Fringilla sp. FRINID fringillid sp. FRININ fringilline sp. HARHAW HRLHAW "Harlan's" (Red-tailed) Hawk HRSHAW Harris' Hawk INHMYN COMMYN Indian House [=Common] Myna HILMYN Indian Hill [=Hill] Myna PASSER PASR Passer sp. PASINA Passerina sp. PASINE passerine sp. PROCEL PROCID procellariid sp. PROCIF procellariiform sp. WILWAR WLSWAR Wilson's Warbler WLWWAR Willow Warbler YELLOW YELLEG yellowlegs sp. YELTHR yellowthroat sp.Note: Names starting with "Mc" or "Mac" are treated as one word. Code
MAGWARwould otherwise be a collision between MacGillivray's and Magnolia warblers.