Bat: the Bible calls it a bird"Birds" is a case in point in regards to biblical definitions. While modern biology does not include bats among the taxonomic class of birds, the Bible groups them together into one category. The term in Hebrew used here for birds (ohf, עוף) comes from a verbal root meaning "to fly," although some of the species of birds listed cannot actually fly.1
In each of the other categories of animals, the Bible gives us general rules by which we can determine whether or not a species of animal is kosher. With birds, no such rule is given. People often look at the list of species prohibited by the Bible and note that many of them appear to be birds of prey or scavengers; however, it is critical to note that Scripture never mentions such a pattern. Rather, the text seems to indicate that there is a considerable but finite list of non-kosher birds. It would appear that all other birds may be eaten, regardless of their physical characteristics or diet.
However, we are presented with a serious problem regarding the list of non-kosher birds. Jewish tradition is uncertain about the exact identity of many of the twenty birds that are proscribed. Most of the time we take for granted the important role Jewish tradition plays in preserving the meanings of Hebrew words. If it had not been for Jewish tradition, Hebrew would be as obscure as the language of the ancient Mayans. It is only because of Jewish tradition that we can read and translate the Hebrew Bible.The meanings of many words (such as tzitzit, ציצית) would be a complete mystery. The vocalization of the text (i.e. the placement of vowels and accents), which can have a significant impact on meaning, could only be speculated since it was preserved orally until about one millennium ago. For that matter, it was Jewish tradition that decided what books are authoritative and included in the canon in the first place. But in this case, we are at a loss because tradition is unable to provide us with answers.
Pigeons: a kosher species of bird (source)Our English translations, unfortunately, do not typically communicate that uncertainty. They do their best to find a likely candidate for each bird named and leave it at that. This is particularly the case in Christian translations, where the editors would see no practical reason for someone to need to know the exact identity of each bird, since they believe that kosher law no longer applies.2 Among Jewish Bibles, the JPS Tanakh (Jewish Publication Society) mentions in a footnote that "a number of these cannot be identified with certainty," and the Stone Edition Tanach (ArtScroll/Mesorah Publications) leaves many of them untranslated with suggestions in footnotes.
As a result of that uncertainty, the Jewish community has taken the approach that to be safe, one must only eat birds for which there is a reliable tradition that it is kosher. This may seem like a drastic measure, but it is the only way to be certain to avoid the species that are off-limits.
Some of the birds that are considered "safe" are chicken, ducks, geese, turkeys,3 pheasants, doves, and pigeons. Most birds typically eaten in Western cultures fall into this category, although recently ostrich and emu farms (both non-kosher) have become more mainstream.4