We already knew that this has been a gruesome year for the buffalo of Yellowstone National Park. But a recent flight by park service personnel has given us a new understanding of just how terrible the toll has been on America’s iconic free-roaming herds.

The flight was an aerial survey to assess the health of the rapidly diminishing herds. The resulting park service estimates surprised even those of us who have been fighting for fundamental changes to the unnecessarily brutal buffalo management practices of the park service and State of Montana. Their population models estimate that only 1,950 to 2,150 buffalo are left in the park. That means that more than half of the 4,700 animals that were a part of the herds going into the winter were killed off---most of them rounded up for slaughter by Montana wildlife officials as the buffalo approached park boundaries. This is the largest death toll since the 19th century, when we nearly wiped the species off the planet.