A bird chatas is offered below [the Altar’s Red Line], and an animal chatas [is offered] above [the Red Line]. A bird olah is offered above [the Red Line], and an animal olah [is offered] below [the Red Line]. If he deviated in this [case] or in that [case], [the offering is] invalid.  The order of pairs [of bird-offerings] is as follows: [In] the [pairs brought for an] obligation, one [bird] is a chatas and one [bird] is an olah; in [pairs brought for] vowed-offerings and donated-offerings, they are all olos.  What is a vowed-offering? One who says: “It is hereby incumbent upon me [to bring] an olah-offering.”And what is a donated-offering? One who says: “This [bird] is [hereby sanctified as] an olah-offering.”  What is [the difference] between vowed-offerings and donated-offerings? Only that regarding the vowed-offerings, [if] they died or were stolen, he is responsible for [replacing] them, and [regarding donated-offerings, [if] they died or were stolen, he is not responsible for replacing them.