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The national Atlas Working
Group, and locally the HOS Atlas Steering Group, agreed the basics for
the Atlas field methodology. The approach gives broadly similar methods
in summer and winter and has a good balance of methods for different
levels of involvement and skill. Below are some of the key points,
beginning with a reminder of what the Atlas aims to do and what the
fieldwork aims to provide.
Aims of the HOS Atlas
project
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To produce dot
distribution maps showing in which tetrads (2-km squares) each
species winters or breeds. (10-km squares for the national project)
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To produce maps
showing broad patterns across Hampshire of relative abundance during
winter and the breeding season. (Britain & Ireland nationally)
·
To measure changes in
distribution and abundance patterns since earlier Atlases.
To fulfil these aims,
Atlas fieldwork in Hampshire must provide:
Seasons
Winter = beginning of
November to end of February; four winters, 2007/08 to 2010/11.
Breeding Season =
beginning of April to end of July; four seasons, 2008 to 2011.
General principles for
both seasons
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Fieldwork comprises ‘Roving
Visits’ and ‘Timed Tetrad Visits’ – the two together
providing the total species list and evidence of breeding, and the
latter providing the essential abundance data.
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Both types of visits
are equally important.
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Roving Visits
are free-format – simply records of species with the aim of amassing
comprehensive species lists for each tetrad (or 10-km square
nationally). Such records might be a result of a day’s birding
through a number of tetrads, or perhaps dedicated searches of the
habitat in one or two tetrads for hitherto missed species.
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Timed Tetrad
Visits (TTVs) are more structured:
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Each Timed
Tetrad Visit in Hampshire should be for two hours,
during which individuals of each species seen and heard are
counted. Observers can of course continue after the two
hours on a Roving Visit basis, to search for species not
already encountered or to seek further evidence of breeding.
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In a season
(winter or summer) there should be two such visits, one
early and one late. For winter this means one visit in Nov-Dec
and one in Jan-Feb. For the breeding season this means one in
Apr-May and one in Jun-Jul. A tetrad need only be surveyed in
one summer and one winter.
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The aim will
be for all of Hampshire’s 1000+ tetrads to receive
Timed Tetrad Visits.
Evidence of breeding
Levels of breeding
evidence (e.g. bird singing; bird with food; nest with eggs) are being
sought from both Timed Tetrad Visits and Roving Records.
Evidence of breeding is also being built into BirdTrack as an optional
field to facilitate further data capture.
Want to know more ?
Please take a look at the
“How can I help” section of the Atlas information on this website.
Glynne Evans Chairman, HOS Scientific Committee & Atlas Steering
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