Vulo (noun): a gorean tawny-colored poultry bird, similar to a pigeon, which also exists in the wild; used for meat and eggs. Also mentioned at Mariners and Rebels are message or messenger vulos.
Behind them another four haruspexes, one from each People, carried a large wooden cage, made of sticks lashed together, which contained perhaps a dozen white vulos, domesticated pigeons.
. . .
Even from where I stood I could see the pigeons pecking at the grain in reassuring frenzy.
Nomads of Gor Book 4
"I am in touch with the negotiations being pretended in the holding of Temmu," he said. "Message vulos keep me informed, and I have intelligence by tarn, as well.
Rebels of Gor Book 33
Book 4: Nomads of Gor, pages 1 and 84 Book 8: Hunters of Gor, page 34 Book 10: Tribesmen of Gor, page 48; Mariners of Gor, Rebels of Gor