Each instance represents one kind of bird seen within a circle-year.
The concatenation of these columns relates each instance to the effort table.
An integer value that orders census records within a year according to their published order.
These three values identify the type of bird. See
Section 3.6, “Kind of bird”. The
.form value is always uppercase and
right-blank-padded to a length of six. The
.rel value is
"/". If the
.rel is not blank, the
.alt_form attribute is the second bird
code, also uppercased and right-blank-padded to six
" " or
" " or
Count of birds as an
int. The value
may be −1 to signify an unknown count.
There used to be at least one row in this table
that had a zero census, which is an error.
(Audubon's database, by contrast, uses zero for
count-week birds and never shows a value of