Temporal and sex-specific variation in growth rates of Marabou Stork Leptoptilos crumeniferus chicks

The nesting success of Marabou Storks Leptoptilos crumeniferus breeding in north-eastern Swaziland is closely associated with rainfall. The reasons for this relationship are not known but may be related with food intake and growth of the chicks. This study set out to determine whether sex, hatching date and sequencing of laying affected the growth rate of chicks. Nestlings were measured weekly from hatching until they died or fledged. Nestling development is described in detail and photographs of different-aged chicks are presented. Male and female chicks differed in growth rate and asymptote for mass, but only in asymptote for wing length. Furthermore, chicks that hatched from eggs laid earlier differed from those laid later in asymptote for wing length and growth rate for mass. Date of hatching had no effect on growth rates. Marabou Storks appear to be slower growing than expected for the Ciconiidae.