TT #27 · Parashas Noach · Second Aliyah · Passuk 7:14
They, and every beast according to its kind, and every animal according to its kind, and every creeping thing that creeps on the earth according to its kind, and every bird according to its kind, every winged bird.
Torah Temimah points to Chullin 139b (distinction between “tzippor” and “kanaf”).
E-Daf image — Chullin 139b (size=3)
Shas / HebrewBooks PDF of the daf
English: “Every bird, every wing” — “tzippor” refers to the pure species; “kanaf” refers to the impure.
Custom (assignment of the two avian terms to pure versus impure species).
“Tzippor” designates the pure birds; “kanaf” designates the impure birds that also entered the ark.