This move by the FWS comes on the heels of a new study released in mid-February by the Wildlife Conservation Society that documents the sudden disappearance of jack rabbits from the Greater Yellowstone Ecosystem. Once abundant throughout Yellowstone and Grand Teton parks, the white-tailed jack rabbit is now a (very) rare sighting; the last documented sighting in Yellowstone was 1991. The decline in population has occurred within the last ten to twenty years and went largely unnoticed. The study was unable to pinpoint a cause for the disappearance – it could be disease, predation, hard winters or a combination of factors. In any case, the study points out that the loss of jack rabbit prey will affect wolves, coyotes, lynx, and other small predators. Jack rabbits are usually a primary source of food for lynx, and their decline may seriously affect the long-term recovery.