Action: Provide supplementary water to increase survival or reproductive success
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A controlled study in Morocco found that water supplemented northern bald ibis Geronticus eremite pairs had significantly higher reproductive success than those far from water sources.
In arid environments water supply may be as much of limiting factor as food supply and providing drinking water may increase survival, particularly of chicks.
Supporting evidence from individual studies
A controlled, multi-year study between 1998 and 2002 in coastal semi-desert steppe in southern Morocco (Smith et al. 2008) found that northern bald ibis Geronticus eremite pairs nesting less than 1 km from supplementary water points had significantly higher reproductive success than pairs nesting more than 5 km from water points (all nests: 1.0-2.2 fledglings/nest for nests close to water vs. 0.37-1.6 fledglings/nest for distant nests; only successful nests: 1.3-2.4 fledglings/nest vs. 1.0-2.3 fledglings/nest). There were no differences in clutch size between treatments, so the authors suggest that differences in productivity were due to failure rates, with 11% of 105 nests close to water failing, compared to 38% of 74 nests far from water. The increase was greatest in years of low natural rainfall but apparent in all years.