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5.3.  Preparing the alternate forms (.alt) file

Because field records do not always use the latest names, and because the reported forms are not always standard species, you must prepare an “alternate forms” file enumerating all the forms that have a six-letter code but which are not standard species names.

You must prepare an .alt file for each .std file, reflecting the exact lumps, splits, and names of the standard arrangement. The file must be named f.alt, where f is the same prefix as that of the .std file.

For example, if the standard file for the AOU Check-List, 6th. ed., including supplements through the 40th, is called aou640.std, the corresponding alternate names file must be called aou640.alt.

In the .alt file you will place several different types of records. Each line starts with the six-letter code being defined, followed by a record type code, and a variable length tail.

5.3.1.  Higher taxon records in the .alt file

For each form above species rank in the hierarchy, enter a line of this format:

  1. Enter the six-letter code. If the code is shorter than six letters (e.g., HAWK), right-pad it to length with spaces.

  2. Enter one space. This signifies that the record is for a higher taxon.

  3. Enter the scientific name of the higher taxon to which this code is referred. This name must be defined in the .std file.

  4. Enter one slash (“/”), then the English name.

  5. In most cases, you are done. However, if the English name requires some markup to be represented correctly in typeset output, enter another slash, followed by the English name formatted according to the TEX typesetting system.

In the optional TEX name field, two TEX macros are used:

  • The \sp macro takes one argument and formats it in italic followed by “sp.” in Roman type. Here is the TEX definition of this macro:

    \def\sp#1{\itc{#1} sp.}%

  • The \itc macro formats its argument in italics, followed by the italic correction (\/). Here is its definition:

    \def\itc#1{{\it #1\/}}%

Here are some complete examples of higher-taxon records.

albatr Diomedeidae/albatross sp.
accipi Accipiter/Accipiter sp./\sp{Accipiter}
laracc Accipiter/large Accipiter sp./large \itc{Accipiter} sp.

5.3.2.  Direct equivalent records in the .alt file

For each non-standard code that is the exact equivalent of a standard code, create a record in the alternate forms file with this format:

  1. Enter the non-standard code, left-justified in the first six columns.

  2. Enter an equal sign (=) in the seventh column. This is the record type code for an exact equivalent.

  3. Enter the standard six-letter code for the new name, left-justified in the next six columns.

  4. Enter one space, followed by the English name (for annotation purposes).

Examples of direct-equivalent records:

amboys=blkoys Oystercatcher, American Black
amewid=amewig Widgeon, American
watpip=amepip Pipit, Water


The form after the equal sign must be defined elsewhere in the standard or alternate forms file. A direct-equivalent record may refer to a code in another direct-equivalent record, but ultimately the chain of references must lead to an actual taxon.

The program will detect cases where there is a cycle in the chain of references. For example, if BRNOWL refers to COBOWL, but COBOWL refers to BRNOWL, that is an error.

5.3.3.  Subspecific forms records in the .alt file

There are several reasons for assigning codes to forms that are a subset of a standard species:

  • Subspecies in the strict taxonomic sense, such as Myrtle Warbler (a subspecies of Yellow-rumped Warbler).

  • Color morphs, such as Blue Goose (a morph of Snow Goose).

  • Recognizable forms of uncertain taxonomic status, such as Pink-sided Junco (an identifiable form of Dark-eyed Junco).

So we use the term “subspecific form” loosely, to mean any identifiable form that refers to some subset of a standard species. For each such code, enter a line with this format:

  1. The six-letter code being defined.

  2. A less-than (<) symbol. This is the record type code for a subspecific form record.

  3. The six-letter code of the standard species that contains this form.

  4. One space, followed by the English name of this form.

  5. In most cases you are done. However, if the English name needs TEX markup to appear correctly in typeset output, append a slash, followed by the TEX-encoded English name.

Examples of subspecific form lines:

agpchi<grpchi Attwater's Greater Prairie-Chicken
agwtea<gnwtea Teal, American Green-winged
alcgoo<cangoo (Aleutian) Canada Goose
axetea<gnwtea teal, (American x European) Green-winged
blugoo<snogoo Blue Goose
branth<brant  Brant (hrota)/Brant (\itc{hrota})

5.3.4.  Collision records in the .alt file

In order to record all the known collisions—that is, cases where two or more names encode to the same six-letter abbreviation according to the rules for abbreviation formation—you must add to the alternate forms file one line for each collision. Each such line enumerates all the disambiguations, that is, the substitute form codes that are preferred:

  1. Enter the collision code in the first six columns.

  2. Enter a question mark (?) in the seventh column.

  3. Type all the disambiguations separated by colon (:) characters.

Examples of collision records:

columb?colba :colbid:colbin

The first example shows that two names collide for the code barowl. The forms are Barred Owl (which is given the substitute code brdowl in the standard forms file) and Barn Owl, with substitute code brnowl.

The last example shows a three-way collision for code columb between the codes for genus Columba, family Columbidae, and subfamily Columbinae. Note that a collision record may refer to forms other than standard taxa.