Invertebrate diet of the Houbara Bustard Chlamydotis [undulata] macqueeniiin Abu Dhabi from calibrated faecal analysis

The ecology of the Houbara Bustard Chlamydotis [undulata] macqueenii is poo rly known and populations are declining due to hunting and habitat loss. As wintering populations in Abu Dhabi may be limited by habitat and food, we studied the diet using calibrated faecal analysis. Prey were categorized in to 16 groups and fed to captive birds under controlled conditions. We calcu lated the recovery rates of prey following digestion and identified consist ent fragments for each group. Wild Houbara Bustard faeces were collected an d examined for key fragments, and initial prey intake was calibrated. Plant remains were identified and their contribution was estimated. Fewer than 2 8% faeces contained > 50% plant material by volume and only 12% contained 9 5% or more. Numerically, the most important prey were: ants (64%), large no cturnal tenebrionids (14.5%), small climbing tenebrionids (12%) and diurnal tenebrionids. However, the Tenebrionidae contributed 97% of the animal bio mass. The relative proportions of prey in the diet were similar to relative abundance as assessed by pitfall trapping. Estimates of the energetic valu e of the prey suggested that on average Houbara Bustards must consume aroun d 670 desert invertebrates/day to meet energy needs. The effort required to catch these prey may vary at least ten-fold seasonally. On average plants could provide a further 6.4-14% energy but more work is needed on this. Whe ther Houbara Bustards wintering in Abu Dhabi are prey-limited depends on pr ey densities and renewal rates which remain unknown.