One study found that use of honeyguides by the Boran people of East Africa reduces their search time for honey by approximately two-thirds. Because of this benefit, the Boran use a specific loud whistle, known as the "fuulido", when a search for honey is about to begin. The "fuulido" doubles the encounter rate with honeyguides. Another study of the Yao honey-hunters in northern Mozambique showed that the honeyguides responded to the traditional "brrrr-hmm" call of the honey-hunters. The chances of finding a bee-hive were greatly increased when the traditional call was used. That study reported anecdotes from Yao honey-hunters that adult but not juvenile honeyguides respond to the specific honey-hunting calls.