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Collisions in the six-letter bird code system

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 MAGWAR would otherwise be a collision between MacGillivray's and Magnolia warblers.
Next: The six-letter bird code system in its entirety
See also: A robust bird code system: the six-letter code
Previous: Rules for the six-letter bird code system
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John W. Shipman, john@nmt.edu
Last updated: 1996/01/21 20:02:29
URL: http://www.nmt.edu/~shipman/z/nom/6coll.html