OSSIFRAGE, os’ ə frij (פֶּ֔רֶס, Lev 11:13, KJV, RSV; gier eagle ASV, Deut 14:12; ossifrage KJV, gier eagle ASV, vulture RSV). Coming second only to נֶ֨שֶׁר in the list this may be taken as a very large bird; the root means “breaker” (of bones) and this suggests those vultures that have acquired this manner of feeding on the marrow after the flesh has been eaten. Three species in particular practice this, the two black vultures and the lammergeier, or bearded vulture. These are still resident in Pal. in small numbers. (See Osprey.)
International Standard Bible Encyclopedia (1915)
The great bearded vulture known as the lammer-geier (Le 11:13; De 14:12 the King James Version, the Revised Version (British and American) "gier-eagle"). The Hebrew name perec means "to break." Let oasis, "bone," and frangere, "to break," indicate the most noticeable habit of the bird. It is the largest of the vulture family, being 3 1/2 ft. in length and 10 in sweep. It has a white head, black beard on the chin, and the part of the eye commonly called the "white" in most animals, which is visible in but few birds, in this family is pronounced and of a deep angry red, thus giving the bird a formidable appearance. The back is grayish black, the feathers finely penciled, the shaft being white, the median line tawny. The under parts are tawny white and the feet and talons powerful. It differs from the vulture in that it is not a consistent carrion feeder, but prefers to take prey of the size captured by some of the largest eagles. It took its name from the fact that after smaller vultures and eagles had stripped a carcass to the last shred of muscle, the lammergeier then carried the skeleton aloft and dropped it repeatedly until the marrow from the broken bones could be eaten. It is also very fond of tortoise, the meat of which it secures in the same manner. As this bird frequents Southern Europe, it is thought to be the one that mistook the bald head of Aeschylus, the poet, for a stone and let fall on it the tortoise that caused his death. This bird also attacks living prey of the size of lambs, kids and hares. It is not numerous and does not flock, but pairs live in deep gorges and rocky crevices. It builds an enormous nest, deposits one pinkish or yellowish egg, and the young is black. It requires two years to develop the red eyes, finely penciled plumage and white head of the adult bird. It was included among the abominations because of its diet of carrion.