וְהִזָּ֞ה מִדַּ֤ם הַחַטָּאת֙ עַל־קִ֣יר הַמִּזְבֵּ֔חַ וְהַנִּשְׁאָ֣ר בַּדָּ֔ם יִמָּצֵ֖ה אֶל־יְס֣וֹד הַמִּזְבֵּ֑חַ חַטָּ֖את הֽוּא׃
Y rociará de la sangre de la expiación sobre la pared del altar; y lo que sobrare de la sangre lo exprimirá al pie del altar; es expiación.
Mishnah Zevachim
How was the hatat of a bird sacrificed?He pinches off its head behind its neck, but he did not sever it. And he would sprinkle its blood on the wall of the altar. The residue of the blood was drained out on the base. Only the blood belonged to the altar, while the rest of it belonged to the priests.