116 Spotted Crake habitat use
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 115–134
The Spotted Crake
Porzana porzana
remains
an extremely poorly known species, despite
its apparent global abundance and
widespread distribution. In 2000, it was
estimated that the size of the population that
breeds in Europe and Asia and winters in
Africa and India was between 100,000 and a
million individuals, with most likely
70,000–110,000 breeding in Europe, which
at that time was thought to constitute
50–74% of the global population (Rose &
Scott 1994; BirdLife International 2004). The
species likely declined dramatically across
Europe in the mid-nineteenth century, at
least in areas subject to rapid improvements
in agriculture, where drainage of extensive
areas and small wetland biotopes removed
Spotted Crake habitat from the fabric of the
landscape (
e.g
. Holloway 1996). However,
even in recent years, it is very difficult to
obtain evidence for its status and
abundance. Assessments in the late 1980s
suggested that, in countries where trends
were known, a quarter of the European
population has declined since the 1970s
(Tucker & Heath 1994), and these trends
seem to have continued thereafter
(Koskimies & Dvorak 1997; BirdLife
International/European Bird Census
Council 2000). Because of its comparative
rarity, generally unfavourable conservation
status and its inclusion on Annex I of the
European Birds Directive, the species is of
high conservation concern. As such,
Member States of the European Union are
obliged to designate Special Protection Areas
(SPAs) for the species, yet very little is known
about its abundance, distribution, habits and
habitat requirements during the breeding
period.
The number of Spotted Crakes breeding
in Denmark was estimated at
c
. 64 singing
males in 2007 when the last formal
assessment was undertaken, and the species
was considered to have increased by 50–
80% between 1990 and 2000 (Danish
Ornithological Society 2013). This increase is
in part due to a number of major wetland
restoration schemes which in the short term
at least have created ideal (
i.e
. new shallow
freshwater) conditions for the species,
including on the Skjern River, west Jutland
where up to 12 singing males have been
present in recent years since the re-
establishment of 22 km
2
of wetlands
(Petersen
et al.
2007). Nevertheless, very little
is known about the habitat requirements
of this species (but see Schäffer 1999;
Gilbert
et al.
2002) which tends to exploit
shallow-water wetlands that are potentially
doomed by vegetation succession to become
unsuitable in the absence of natural
perturbations or management interventions
(see Francis 2011 and Stroud
et al
. 2012). For
this reason, it was decided to initiate a pilot
project to attempt to study the behaviour,
movements and habitat use of Spotted
Crake at a major restored wetland, Lille
Vildmose (56º54’N, 10º12’E) in northeast
Jutland, on the site of abandoned peat
cuttings. The species is notoriously difficult
to study or monitor, not least because of its
cryptic and secretive habits and its use of
densely vegetated wetlands which greatly
hamper observations (
e.g.
Stroud
et al
. 2012).
Hence, the project reported here aimed to
map singing birds across the range of
habitats represented at the site to assess
crude selection at a large spatial scale, and
also to see whether birds could be trapped
