I’m curious in Halacha how our sages derived the requirement that for a bird to be kosher it had to have a mesorah?
In Tanakh it doesn’t clearly say this so where does this requirement come from?
Conveniently R Nathan Slifkin has a full article titled Why do we need a Mesorah for Birds? which aims to answer your question. You'll have to read it in full to get the full depth of the answer, but in a nutshell he writes that
Chazal [... gave] four signs via which to distinguish kosher from non-kosher birds (possessing a hind toe, a crop, a peelable gizzard, and not being “predatory”[...]). [...] According to Rashi’s interpretation, the non-kosher birds in the Torah’s list possess the first three of these signs; but in order for a bird to be kosher, it must also be known to be non-predatory. And Rashi says that since it’s difficult to be really sure that a bird is never predatory, one needs a tradition that it is kosher.
Noting that a majority of Rishonim (including Rabbeinu Tam, R. Moshe b. Yosef, Ramban, Ran, Rashba, Ritva, Rif) disagree with Rashi, R Slifkin then goes on to show Shulchan Aruch and Rema (YD 82:2) requires a mesorah to confirm that a bird is kosher to cover Rashi's concern (see Darkei Moshe where he justifies the concern based on the stork). See the full post for details.