Examples from the Web for tiercel
The male peregrine, known to hawkers as the tiercel, is greatly inferior in size to his mate.The Truth About Woman|C. Gasquoine Hartley
He appears to have known a tiercel which flew rooks, and seldom missed as much as one in ten flights.
The tiercel of the saker is more properly called a sakret, sakeret, or sackeret.
It is only rather exceptionally that a tiercel can be got to fly them.
The latter was probably called the tercel, or tiercel, from being about a third smaller than the falcon.The Ornithology of Shakespeare|James Edmund Harting