5.9.
The taxon-group pattern:
biological classification of the birds seen
The taxon-group pattern is a set
of three attributes used to classify the bird
taxonomically:
birdnotes.rnc
taxon-group =
( attribute ab6 { bird-code }, 
( attribute rel { "|" | "^" }, 
attribute alt { bird-code }
)?,
attribute notable { "0" | "1" }? 
)
bird-code = xsd:string { pattern="[a-zA-Z]{2,6}" }
| |
The ab6 attribute is required.
In most cases it specifies the code corresponding to
the name used to describe the classification of the
bird. For a discussion of this code system, see
Section 3.3, “The taxonomic dimension: what kind of bird?”. For example, the code
for Wandering Tattler is wantat:
ab6='wantat'
|
| |
Normally the rel and
alt attributes are absent, and
in such cases the ab6
attribute describes a bird assigned to a specific
species, family, or other taxon.
However, there are two cases where the kind of bird
sighted must be described as two six-letter codes
(ab6 and
alt) and another code
(rel) that describes the
relationship between those codes:
Species pairs: Sometimes
the identification can be narrowed down to a
choice of two forms, but no further. For
example, sightings of certain flycatchers in the
genus Empidonax
are often described as “Dusky/Hammond's
Flycatcher.” In these cases we use
rel='|', for example:
ab6='dusfly' rel='|' alt='hamfly'
Hybrids: The
classification is given as a pair of codes with
rel='^'. For example, a
hybrid of Mallard x Gadwall would be encoded:
ab6='gadwal' rel='^' alt='mallar'
|
| |
Flag unusual records with notable='1'.
Such records should be highlighted so that readers
not interested in routine sightings can more rapidly
skim the reports for “the good stuff.”
|
For species pairs and hybrids, the order is not
important. However, retrieval should always ensure
that the ab6 code is lexically
less than the alt code, so
that records of a given pair or hybrid fall in one
place and not two.
