Tarn (noun): Crested, hawk-like bird large enough to be ridden; used in battle and in racing..

Taken from the book by John Norman, Book 1 in the Gor Series, Tarnsman of Gor...

Though the tarn, like most birds, is surprisingly light for its size, this primarily having to do with the comparative hollowness of the bones, it is an extremely powerful bird, powerful even beyond what one would expect from such a monster. Whereas large Earth birds, such as the eagle, must, when taking flight from the ground, begin with a running start, the tarn, with its incredible musculature, aided undoubtedly by the somewhat lighter gravity of Gor, can with a spring and a sudden flurry of its giant wings lift both himself and his rider into the air. In Gorean, these birds are sometimes spoken of as Brothers of the Wind.

The plumage of tarns is various, and they are bred for their colors as well as their strength and intelligence. Black tarns are used for night raids, white tarns in winter campaigns, and multicolored, resplendent tarns are bred for warriors who wish to ride proudly, regardless of the lack of camouflage. The most common tarn, however, is greenish brown. Disregarding the disproportion in size, the Earth bird which the tarn most closely resembles is the hawk with the exception that it has a crest somewhat of the nature of a jay's.

Tarns, who are vicious things, are seldom more than half tamed and, like their diminutive earthly counterparts, the hawks, are carnivorous. It is not unknown for a tarn to attack and devour his own rider. They fear nothing but the tarn-goad . They are trained by men of the Caste of Tarn Keepers to respond to it while still young, when they can be fastened by wires to the training perches. Whenever a young bird soars away or refuses obedience in some fashion, he is dragged back to the perch and beaten with the tarn-goad. Rings compariable to those which are fastened on the legs of young birds, are worn by the adult birds to reinforce the memory of the hobbling wire and the tarn-goad. Later, of course, the adult birds are not fastened, but the conditioning given them in their youth usually holds, except when they become abnormally disturbed or have not been able to obtain food. The tarn is one of the two most common mounts of a Gorean warrior; the other is the high tharlarion, a species of saddle-lizard, used mostly by clans who have never mastered tarns. No one in the City of Cylindars, as far as I knew, maintained tharlarions, though they were supposedly quite common on Gor, particularly in the lower areas--in swampland and on the deserts.