Abstract :
Time budgets and activity patterns of sandgrouse were studied in semi-arid agricultural land in Spain (Black-bellied and Pin-tailed Sandgrouse) and in more desertic conditions in Israel (Black-bellied and Spotted Sandgrouse). During c. 75% of daylight hours, all four species were either foraging or inactive. The birds in Israel spent more time foraging than those in Spain, despite having lower thermoregulatory costs, reflecting a likely difference in the productivity of the sites. Partitioning of foraging habitat was evident at both sites and, contrary to expectation, it was the larger Black-bellied Sandgrouse which spent the most time foraging. In Israel, Spotted Sandgrouse became inactive at high temperatures whereas the Black-bellied continued to forage, utilizing the shade available in its dwarf shrub foraging habitat. The range of Black-bellied Sandgrouse may be limited by its thermoregulatory ability in hot conditions and its need to forage for long periods.
