Midrasch zu Wajikra 1:15

1) (Vayikra 1:15): "And the Cohein shall bring it near to the altar"): Why "And he shall bring it"? (In context the "it" is superfluous). Because it is written (Vayikra 1:14): "And he shall offer his offering from the turtle-doves or from the young," I might think that he could offer no fewer than two; it is, therefore, written "And he shall bring it near" — even one suffices.

2) "And the Cohein shall bring it near … and he shall pinch off (malak) its head" — whence we are taught that melikah is performed by a Cohein. (For we would otherwise reason:) Is it not a kal vachomer (that a non-priest could also perform melikah), viz.: If a sheep, for (whose shechitah) "north" was mandated (see Vayikra 1:11), a Cohein was not mandated — melikah, for which north was not mandated, how much more so should a Cohein not be mandated! It is, therefore, written: "the Cohein … umalak" — melikah is performed only by a Cohein.

3) I might think that he should perform melikah with a knife. And it would follow by kal vachomer, viz.: If shechitah, for which a Cohein was not mandated, an instrument (i.e., a knife) was mandated — melikah, for which a Cohein was mandated, should it not follow that an instrument be mandated! It is, therefore written: "the Cohein … umalak" — concerning which R. Akiva says: Now would it enter your mind that a non-priest could offer it on the altar? What, then, is the intent of "the Cohein … umalak"? To teach us that melikah must be performed with the body (i.e., with the fingernail) of the Cohein.