The number of wolves in Yellowstone National Park has continued to grow amid a push to remove the gray wolves from federal protection.



New figures from the park show that there were at least 104 wolves in 11 packs in Yellowstone in December last year, including nine breeding pairs, with 40 pups surviving until the end of the year.

The number of wolves is now at its highest level since the predators were introduced back into Yellowstone in 1995 from Canada. Gray wolves had been completely wiped out in the vast national park in 1926, leading to a range of negative ecological changes that their reintroduction helped correct.

The recovery of gray wolves in Yellowstone and elsewhere has prompted legislation that would remove the species from protection under the Endangered Species Act in the midwest and Wyoming. The bill, authored by Republican senators Ron Johnson and John Barrasso, would also stop the courts from overruling the Department of Interior on wolf delisting, following a federal court ruling last year that the states were not providing enough protection for the species.

A group of 26 scientists have reportedly written to the Department of Interior to delist gray wolves where processes are in place to “manage the species”.

But environmentalists say wolves still have a long way to rebound after their numbers were devastated over the past 200 years through shooting, poisoning and trapping. The Center for Biological Diversity estimate that wolves now occupy less than 10% of their historical range.

Yellowstone’s latest surveys also show that a five-year effort to conserve aerial predators such as hawks and eagles has been successful, with numbers of peregrines remaining stable and the nesting success of bald eagles and ospreys “above the long-term averages for both species during the last several years”.

There has also been progress on protect native cutthroat trout in Yellowstone. More than one million lake trout, an invasive introduced species, have been removed from Yellowstone Lake, with the park stating there are now signs that cutthroat trout are beginning to reappear.