And he shall slaughter it on the side of the altar, northward, before Hashem; and the sons of Aharon the kohanim shall dash its blood on the altar, round about.
Source
Sifra, Vayikra Dibbura deNedavah, on 1:11 (“tzafonah before Hashem”).
English: “Northward before Hashem” — there is no north-requirement on a bamah. “It” (the flock animal) is slaughtered northward — and not a bird northward.
In Sifra: North applies only in the Temple/Mishkan precinct (“before Hashem”), not on a private bamah. The pronoun “it” limits the north rule to the animal olah; a bird olah is not forced north by this verse (and in fact melikah has no north requirement).
Type of Learning
Custom (place-phrase + pronoun exclusion).
What Is Learned
Flock olah shechitah must be on the north of the altar in the azarah; bamoth and bird offerings are outside that north rule.