Storks' Diversity, Flock Characteristic, Roosting Ecology and Fluctuation in Numbers in Some Mayas at Dinder National Park, Sudan, During the Dry Seasons 2009 and 2010

Abstract

Storks were studied by directly observing them in the Maya
(meadow) ecosystem of Dinder National Park (DNP) during the dry
seasons of 2009 and 2010. The objective was to determine their diversity,
flock characteristics, roosting ecology and the annual fluctuation in their
numbers. The numbers were ascertained by the double sampling
procedure in which the number of each stork species in a flock was
estimated and was then directly counted. A predictive model was
developed from the relationship between the counted and the estimated
variables. Subsequently, the number was only estimated and the actual
count was predicted from the regression model. The tree density was
determined by the nearest neighbour method. The crown diameters of the
trees were measured, and the crown areas were calculated. Eight species
of storks; namely, the black (Ciconia nigra), the white (Ciconia ciconia),
the Abdim’s (Ciconia abdimii), the yellow-billed (Mycteria ibis), the
African open bill (Anastomus lamelligerus), the woolly-necked (Ciconia
episcopus), the marabou (Leptoptilos crumeniferus) and the saddle bill
(Ephippiorhynchus senegalensis), occurred in DNP. The black and the
white storks are Palearctic migrants, whereas the Abdim's, the woolly-
necked, the African open bill and the yellow-billed are local migrants; the
marabou and the saddle bill are resident. The three species that occurred
in large flocks were the yellow-billed, the marabou and the open bill. The
total number of storks in 2010 was lower than that in 2009. This decline
was attributed to severe drought that struck the DNP in 2010.