Mischna zu Wajikra 5:78

Thirteen rulings govern the carrion of a clean bird:There must be intention; It need not be rendered susceptible; It conveys food uncleanness if its minimum bulk is that of an egg; And it conveys uncleanness when in one's gullet if its minimum bulk is that of an olive; He that eats of it must wait until sunset [to be clean]; Guilt is incurred on account of it for entering the sanctuary; Terumah is burned on account of it; He who eats a limb of it while it is alive suffers forty lashes; Slaughtering it or nipping [off its neck] cleanses it even if it is terefah, the words of Rabbi Meir. Rabbi Judah says: they do not cleanse it. Rabbi Yose says: the slaughtering does cleanse it but nipping does not.

A bird hatat is performed below [the red line], but a beast hatat is performed above [the red line]. A bird olah is performed above, but a beast olah below. If he changed this procedure with either, then the offering is disqualified. The seder [ordered ritual] in the case of kinnim is as follows: In the case of obligatory offerings, one [bird] is a hatat and one an olah. In the case of vows and freewill offerings, however, all are olot. What constitutes a vow? When one says: "It is incumbent upon me to bring an olah." And what constitutes a freewill-offering? When one says: "Behold, this shall be an olah." What is the [practical] difference between vows and freewill offerings? In the case of vows, if they die or are stolen, one is responsible for their replacement; But in the case of freewill offerings, if they die or are stolen, one is not responsible for their replacement.

Antigonus a man of Socho received [the oral tradition] from Shimon the Righteous. He used to say: do not be like servants who serve the master in the expectation of receiving a reward, but be like servants who serve the master without the expectation of receiving a reward, and let the fear of Heaven be upon you.

The area within the wall [of Jerusalem] is holier, for it is there that lesser holy things and second tithe may be eaten. The Temple Mount is holier, for zavim, zavot, menstruants and women after childbirth may not enter it. The chel is holier, for neither non-Jews nor one who contracted corpse impurity may enter it. The court of women is holier, for a tevul yom may not enter it, though he is not obligated a hatat for doing so. The court of the Israelites is holier, for a man who has not yet offered his obligatory sacrifices may not enter it, and if he enters he is liable for a hatat. The court of the priests is holier, for Israelites may not enter it except when they are required to do so: for laying on of the hands, slaying or waving.

Hatat [birds] are on one side, and olot [birds] are on the other and an unassigned [pair] is in the middle: If from the middle pair one bird flew to this side, and one bird flew to this side, then he has not lost anything, because he [the priest] says that the bird that flew [from the middle] towards the hataot is a hatat and the bird that flew towards the olot is a olah. If one [from each side] returns to the middle, then [all] those in the middle must be left to die, but those [left on either side] can be offered up as hataot or as olot respectively. If again a bird [from the middle] returned and flew away to the sides, then all must be left to die. One cannot pair turtle-doves with pigeons or pigeons with turtle-doves. How is this so? If a woman has brought a turtle-dove as her hatat and a pigeon as her olah, she must then bring another turtle-dove as her olah; If her olah had been a turtle-dove and her hatat a pigeon, then she must bring another pigeon as her olah. Ben Azzai says: we go after the first [offering]. If a woman brought her hatat and then died, her heirs must bring her olah; [But if she first brought] her olah and then died, her heirs need not bring her hatat.