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The helicopter rotor spread was 35 ft (10.7 m) but the area affected by the downdraft was 45-50 ft (13.7-15.3 m) in diameter. It was apparent that the agitation of the nesting cover caused by the downdraft, coupled with the noise of the engine, was sufficient to cause ducks to flush. In addition to being faster, cheaper, and more efficient, use of the helicopter has other advantages, such as a reduction in nest desertion due to nest hunting activities. When examined the day following the survey, none of the nests located by the helicopter crew had been abandoned. By kneeling on a pontoon to locate, examine, and mark nests without landing or leaving the hovering helicopter, no human scent is left, the vegetation does not appear disturbed, and no trails are left for predators.