Re: Completeness and reliability of surveys entered into Eremaea Birds.
Anyone registered with Eremaea Birds can enter surveys. The database checks
each survey for unusual records. (An unusual record is defined as one where the
species has not been observed in the one degree block concerned within 12
months of the survey.) If an unusual record is detected, the survey is marked
for review by a moderator, otherwise the survey is automatically included in
the Eremaea Birds atlas (which forms the basis for all public reports). The
task of the moderator is to accept or query the unusual records. The main
purpose of this whole exercise is to prevent data entry errors. The general
policy is to accept observations where the observer is confident of what they
have seen, although the moderator can choose to exclude the survey from the
atlas if they still have serious reservations (a rare occurrence).
Surveys are also sourced from the Eremaea Birds Birdline reports. These are
generally accepted without query since they have already been moderated.
With regard to completeness, an Eremaea Birds survey can be anything from an
incidental sighting to a 24 hour survey. (Surveys can be of longer duration,
but only single-day surveys are included in the atlas). Birdline surveys, of
course, only list highlights. As noted by others, the inclusion of incidental
and "birdline" surveys increases the reporting rates for scarce species and
decreases it for common species. In the end, the reporting rate is the
reporting rate, and it is published in order to give some idea of the liklihood
of occurrence of a species, even though it is heavily distorted by what people
actually care to report.
I hope this helps. Suggestions are always welcome.
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