Vol. 32 – 2006 - Ecologia Mediterranea

MOHAMED BOUKHEMZA, NABILA BOUKHEMZA-ZEMMOURI, JEAN-FRANÇOIS VOISIN, BELKACEM BAZIZ
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Sébaou were highlighted by frequentation
indexes. Direct observations on the hunting and
feeding activities of these two species from
March to July 1995 were also carried out. We
distinguished several categories of preys according
to the occupied habitats. In addition, a
quantitative approach of the diet and feeding
activity of these wading birds was also
approached according to the seasons and of the
attended trophic habitats.
Within locality, the frequentation indexes of the
habitats by these two species varied from one
season to another according to food availability,
which was function of the biological cycle of
preys. The species were both very highly
attracted by plowed fields. Insects largely dominated
all other animal classes in the diet of
both birds, but accounted only for a small part
of biomass intake. Although represented by
small numbers, Vertebrates represented most of
all the consumed biomass. The temporal variation
of the feeding effort parameters showed
the highest intake values during April, nesting
and breeding period for the young. These values
dropped at the time when the young
become independent from their parents. Feeding
activity, expressed in numbers of steps, was
also maximum in April, then dropped therafter.
Hunting efficiency, expressed in terms of failure
percentage, was maximum in summer. The variations
of the feeding effort parameters according
to habitats show that energy intake was
highest in plowlands, and least in the mown
meadows and wetland. Feeding activity,
expressed in step numbers, was maximum in
waste lands. Hunting efficiency, expressed in
failure percentage, was maximum in ploughings
and minimal in the wetlands.
Abriged english version
In Algeria, Cattle Egret Bubulcus ibis lives in
almost all the tellian area. In the Mediterranean
region, except for of Franchimont’s
work in 1986b, few data are available about
the food locations from which the successfully
reproduction of Cattle Egret depends,
contrary to what occurs for nesting sites (Bredin
1981, 1983; Hafner & Fasola 1992). The
white Stork Ciconia ciconia, is considered as
a one of the declining species in the Western
part of its distribution area (Reinwald et al.
1989). In Europe, several works on feeding
ecology have been carried out (e.g. Pinowska
& Pinowski 1989; Dziewiaty 1992; Thomsen
& Struwe 1994). In Algeria, many studies
were undertaken (Boukhemza et al. 1997;
Boukhemza 2001; Boukhemza et al. 2004),
but there is a lack of quantitative data on feeding
activity. The White stork and Cattle
Egret live together in the Sébaou valley. It
seemed convenient enough to see how these
two species, the one (Cattle Egret) which is
described as ubiquist and the other being rare
and in the regression phase, do share food
space and resources during their annual cycle,
from the expenditure and energy profits points
of vues.
The various habitats attended by the white
Stork (Ciconia ciconia) from January to
August 1995 and the Cattle Egret (Bubulcus
ibis) from November 1994 to October 1995
in the Sébaou valley were highlighted by frequentation
indexes. Direct observations on the
hunting and feeding activities of these two
species from March to July 1995 were also
carried out. We distinguished several categories
of preys according to the places of capture.
In addition, a quantitative approach of
the diet and feeding activity of these wading
birds was also achieved during the same period.
It related to the relative estimation of the
expenditure and energy contributions through
some parameters according to seasons and
attended trophic habitats.
In the same area, the frequentation indexes of
the habitats by these two species fluctuated
from one season to the other depending on
food availability, this was function of the
preys biological cycle. In both cases, it is
mostly in June, which corresponds to the takeoff
time of the young generation that the frequentation
indices are highest. It is also at that
time of the year that the most significant activity
of these birds is observed.
The white Stork finds most of its food in the
temporary meadows, the ponds, the ploughed
grounds and the cultures which it attends all
the year. The other habitats, like the refuse
tips, are frequented only in winter. Ploughed
fields were always very highly attractive. This
diagram of frequentation is found in the European
countries such as Denmark, Spain and
Germany (Skov 1991; Coppa 1991; Lestan
1991; Thomsen 1995; Thomsen & Struwe
1994; Marchamaldo de Blas 1995). These
choices of frequentation seem to be dictated
by good conditions such as the preys detection
along with the possibility of moving
without being stopped by the vegetation.
In Kabylie, the Cattle Egret all along the year
attend ploughings, the meadows, the low cultures,
the wetlands and the temporary ponds.
In the Camargue, it is also present all along
the year in the marshes (Voisin 1991), and the
other habitats such as the discharges are frequented
only in periods of food (Hafner 1977;
ecologia mediterranea – Vol. 32 – 2006