Rice paddy-fields have become increasingly important worldwide as
reliable alternative foraging sites for many wading birds due to the
rapid loss or degradation of their natural wetland habitats. While
assemblage and dispersal patterns of these birds are influenced by
spatial distribution of their food resources, foraging activities of
some species contribute significantly to natural suppression of some
organism harmful to agriculture or human health. This 4-month study
investigated how paddy-field management practices influence spatial and
temporal linkage between African Openbill Stork distribution and
abundance to that of its gastropod mollusc prey resources at Ahero Rice
Irrigation Scheme, western Kenya. Regression models predicted African
Openbill Stork abundance's positive response to gastropod prey
abundance, but negative response to conspecific competition abundance.
Stork abundance also increased in response to rice-crop stage, with
highest abundances at mid-crop stages, though only marginally due to
field-flooding. Contrarily, gastropod abundance increased progressively
with rice-crop phases, peaking at transplanting before reducing to
stabilization towards crop maturity and harvesting. Paddy-field-block
size showed no effect on abundances either Openbill Stork or gastropods.
However, paddy block size predicted positive effect on Openbill Stork
abundance when interacted with rice growth stage, and with gastropod
abundance. Conversely, abundance of competing waterbirds, when
interacted with gastropod abundance or rice-crop stage, predicted lower
stork abundance, reaffirming negative impact of conspecific competition
for stork assemblage. The findings demonstrate the significant role of
gastropod food resources in overall distribution and assemblage of
African Openbill Stork, impact of conspecific competition, and the
crucial indirect influence of anthropogenic field management in shaping
these dynamics through agronomic practices especially field flooding
control and rice production cycles generally. The results are applicable
in designing rice-fields as attractive alternative habitats for Openbill
Stork and other waterbirds, to harness their potential contribution to
bio-regulating the gastropod vectors of schistosomiasis.