Hilchos Bikkurim 1:7

The five gifts that kohanim acquire everywhere are the designated parts of slaughtered animals, the money of pidyon haben (redeeming a firstborn son), the sheep used to redeem a firstborn donkey, the stolen property of a convert (who died and left no heirs to return it to) and dedicated property (charamim). These five gifts are secular in nature.

Hilchos Bikkurim 1:8

The gift that the kohanim acquire from the Temple is the hide of a burnt offering. This includes the hides of other sacrifices of the highest sanctity, all of which are given to the kohanim.