The seasonality of group size and group composition of sand partridge (Ammoperdix heyi heyi Temminck, 1825) in the Ibex Reserve, Saudi Arabia

Th e seasonality of group size and composition in sand partridges was studied at the Ibex Reserve in central Saudi Arabia. Mean group size and flock encounter rate were signifi cantly related to rainfall and temperature. During winter and the breeding season (March to April), the encounter rate on the valley floors was distinctly lower than that observed during summer. Although encounter rates did not differ signifi cantly between valleys, sand partridges were more likely to be encountered in narrow, stony valleys. Correcting for valley width, encounter rates did not differ between valleys. Male and female encounter rates were constant throughout the reserve, indicating a constant sex ratio throughout the year. Results are in line with earlier findings reported from more northern habitats such as the Eilat Mountains (Israel) and the Rum Wildlife Reserve (Jordan). Human disturbance in parts of the reserve is high and may have an impact on group size and composition.