birds with chicks from entering fields that are about to be mown by erecting
“flags” made out of bamboo canes with blue or white plastic bags attached to
their tops (Kruk et al. 1997).
Chick mortality can also be reduced by altering the pattern of mowing. Fields
are normally mown from the outside of the field inwards. This concentrates
chicks in an ever-decreasing island of unmown grassland until this is itself cut,
killing the chicks. Mowing from the center of the field outward allows chicks to
escape to surrounding fields, and together with leaving strips of suitable habitat
along field margins has been used to increase productivity of Corncrakes in the
United Kingdom (Tyler et al. 1998) (Figure 14.4).
14.5.5Using fertilizer
The attractiveness of grassland to some types of geese can be increased by re-seeding
unproductive swards with more nutritious grasses, such as Perennial Rye Grass
Lolium perenne(e.g. Percival 1993), and by fertilizing the sward with nitrogenous
fertilizer (Owen 1975; Percival 1993; Vickery et al. 1994). Care should always be
taken to minimize run-off and leaching. Reseeding and/or fertilizer application will
damage any existing botanical, invertebrate, or breeding bird interest of a grassland.
342 |Habitat management
Fig. 14.4Mowing regimes can be altered to minimize the loss of nests and chicks of
ground-nesting birds. Delaying mowing until after breeding is one method. Corncrakes
(inset), though, require uncut grassland throughout the summer, so strips of unmown
grassland are left on field edges to retain suitable habitat for them. (RSPB Images)