2,278. The Signs of Kosher Birds

Maachalos Assuros 1:15

One who is familiar with the non-kosher species of birds and their names may eat a bird of any other species. Kosher species of birds are eaten based on tradition, i.e., it’s accepted in a given locale that a certain species of bird is kosher. A hunter’s word is accepted if he says that his mentor taught him that a certain bird is permitted so long as the mentor has an established reputation of being familiar with the species of birds and their names.

Maachalos Assuros 1:16

One who doesn’t recognize the species of birds and doesn’t know their names must check the signs of non-kosher birds as taught by the Sages, i.e., any bird that attacks with its claws and eats is known to be from one these species and is not kosher. If a bird doesn’t attack with its claws and eat, it’s kosher so long as it has an extra claw, it has a crop or its craw can be peeled by hand.