Rebhuhn. Schlussbericht 1991–2000 - BAFU

Skylarks and common kestrels have been investigated more in detail.
Skylark territories containing wild-flower strips were smaller than those with arable
farmland only. For skylarks wild-flower strips were more attractive as nesting habitat
and for searching food than all the other crop types. Wild-flower strips did
have a beneficial effect on nestling growth of skylarks. Wild-flower strips are attractive
to common kestrels as hunting grounds. During winter food supply for
common kestrels was better because of higher mice densities in the wild-flower
strips. However, since common kestrels change during winter from hunting by hovering
to the more energy-saving hunting from posts and such sites are lacking in
the open landscape, the birds can benefit only partly (in spring and autumn) from
the better food supply.
To summarise, the conclusions of the investigation are:
A. some threatened breeding bird species of open and semi-open farmland can be
supported by ecological compensation measures on condition of the following:
a) the ecological compensation areas have to be rich in plant species and structures
(e.g. sown or spontaneous wild-flower strips),
b) at least 5% of the productive land has to be of a superior quality,
c) the ecological compensation areas form (together with existing structures) a
web of habitats.
B. On productive arable farmland the problems of endangered bird species cannot
be solved with the measures provided by the legal framework alone, since quantity,
quality and the spatial arrangement of the ecological compensation areas do
not satisfy the needs of more demanding breeding bird species.
Rebhuhn. Schlussbericht 1991–2000 19