• תורים must be mature, בני יונה must be young

The next Mishnah states: כשר בתורין פסול בבני יונה – what is acceptable [as a korban] regarding turtledoves is not acceptable regarding pigeons, and vice versa. תחלת הציהוב – The beginning of yellowing (an intermediate stage) of both types of birds is פסול. A Baraisa explains that תורין must be גדולים – mature, whereas בני יונה must be קטנים – young, but young תורין and mature בני יונה are invalid. Another Baraisa explains that although one might have thought that young תורים should be valid based on a kal vachomer from בני יונה, or mature בני יונה should be valid based on a kal vachomer from תורים, the pesukim indicate to us that each type is specific, and Rava explains: לא לישתמיט קרא ולכתוב – no passuk slips away from the standard usage and writes: מן בני התורים או מן היונה – from young turtledoves or from pigeons; the Torah always writes "בני יונה", young pigeons. Although "תורים" might have allowed for both young and mature turtledoves, we compare תורים to בני יונה: just as only young בני יונה are valid, so too only mature תורים are valid.

• Defining from when תורים and בני יונה are valid

A Baraisa darshens "מן" התורים – “from” the turtledoves and "מן" בני היונה – “from” the pigeons to exclude the intermediate stage of תחילת הציהוב – beginning of yellowing (when it develops yellow feathers around its neck), which is invalid for both types of birds. מאימתי התורים כשרים – From when are turtledoves valid as korbanos? משיזהיבו – From when they turn gold, and have completed the intermediate stage. בני יונה become invalid (too old) משיצהיבו – from when they turn yellow, thus reaching the intermediate stage. Yaakov Korchah taught a Baraisa which defines the earliest stage from when בני יונה are valid as "משיעלעו". He explained this refers to the passuk: אפרוחיו יעלעו דם – its young chicks swallow blood. Abaye identifies this stage: מכי שמיט גדפא מיניה ואתי דמא – from when one pulls a feather from it and it bleeds.

• Is תחלת הציהוב – beginning of the yellowing of birds disqualified as a ספק, or as a בריה?

Rebbe Zeira asked: if one vowed to bring an עולה either from תורים or בני יונה (whichever he chooses), and he brought both types of birds when they were in the stage of תחלת הציהוב – the beginning of yellowing, what is the halachah? ספיקא הוי ונפיק – Is such a bird normally disqualified because it is of doubtful status (whether it is considered young or mature), and in this case he is יוצא (since he brought both types, ensuring that whichever status it is, one עולה was valid)? או דילמא בריה הוי ולא נפיק – Or perhaps it is disqualified because it is an independent entity, neither young nor mature, and he was not יוצא in this case, because both birds are disqualified? Rava suggests a proof from the Baraisa which darshens "מן" to disqualify תורים or בני יונה from being used during תחלת הציהוב. If this stage is considered a בריה, it is understood why the passuk would be needed to disqualify it. But if it is a ספק, איצטריך קרא למעוטי ספיקא – is a passuk needed to exclude a matter of doubt?! But there is no matter of doubt before Hashem as to its status!? The Gemara answers that the passuk is actually darshened to teach something else entirely (and the Baraisa brought this passuk as a mere אסמכתא).

Siman – Cab. The cab that picked up the young turtle dove and the old pigeon when they were told they were פסול for a korban, after dropping off a turtle dove with golden feathers, and a pigeon that was bleeding from a pulled feather which were valid, was from תחילת הציהוב Cab Services, and driven by a bird in that proudly introduced itself as a בריה, not a ספק.