Midrash for Chullin 55:5

R. Elazar Hakappar says: Now what did we learn from deer and hart? It came (ostensibly) to teach, but it (in the end) it was found to be taught, viz.: Just as a beast (must be slaughtered) through shechitah, so, an animal (e.g., deer and hart), through shechitah, (but a bird [must be slaughtered through shechitah] only by ordinance of the scribes). Rebbi says: "as He commanded you" (Ibid. 21) apprises us that Moses was commanded as to gullet and windpipe (as being the loci of shechitah) and as to the (cutting of) the major portion of one (of these being the criterion for shechitah) in a bird and of both, in a beast.