Interior Secretary Ryan Zinke arrives for his first day of work at the Interior Department in Washington on Thursday, riding Tonto, a 17-year-old Irish sport horse. (Interior Department via AP)

Arriving on horseback Thursday, newly minted Interior Secretary Ryan Zinke pledged he would devote more resources to national parks, boost the morale of department employees and bolster the sovereignty of American Indian tribes.

Zinke — who was confirmed by the Senate on Wednesday by a 68-to-31 vote — rode with a nine-person mounted police escort to the Interior Department’s downtown headquarters on Tonto, an Irish sport horse. The horse, a bay roan gelding standing just over 17 hands tall, is normally kept in stables on the Mall and is owned by the U.S. Park Police.

While the Park Police serve as the interior secretary’s regular security detail, officers are typically not mounted.

Within hours of his arrival Zinke signed two secretarial orders, including one that overturned the U.S. Fish and Wildlife Service’s guidance to agency managers to phase out the use of lead ammunition and fishing tackle on national wildlife refuges by 2022. Several gun rights and hunting groups had objected to the policy, which was instituted just before Barack Obama left office, on the grounds that non-toxic copper and steel shot is somewhat more expensive.

In the new directive, Zinke wrote, “I have determined that the Order was not mandated by any existing statutory or regulatory requirement and was issued without any significant communication, consultation, or coordination with affected stakeholders.”

Advocates of the previous order, however, noted that it set in motion a five-year consultation process between federal officials and the states. Lead poisoning–which takes place when fragments of shot are consumed by scavengers or absorbed into the surrounding environment–is estimated to kill between 10 and 20 million birds each year, along with other species.

George Fenwick, president of the American Bird Conservancy, criticized the move in statement, saying, “How shameful that this administration is casting science aside along with the welfare of wildlife.”

Zinke’s second order aims to expand access to public lands for outdoor recreation and fishing; representatives from 15 organizations ranging from the Boone and Crockett Club to the National Rifle Association and Ducks Unlimited joined him as he signed the two directives.

A fifth-generation Montanan, Zinke also sent an email to the department’s 70,000 employees telling them that he had spent years working on public lands issues and was dedicated to protecting America’s natural heritage.

“I approach this job in the same way that Boy Scouts taught me so long ago: leave the campsite in better condition than I found it,” he wrote in a missive that was later posted on Medium. “I’m an unapologetic admirer and disciple of Teddy Roosevelt. I believe in traditional mixed use ‘conservation ethics’ doctrine laid out by [Gifford] Pinchot, but realize that there are special places where man is more an observer than a participant, as outlined by [John] Muir.”

An employee with the Bureau of Indian Affairs from Montana’s Northern Cheyenne tribe played a veterans honor song on a hand drum as Zinke approached the department on C Street NW, while 350 employees waited outside to greet him. In his email, Zinke noted that he was “proud to be an adopted member of the Assiniboine-Sioux from Northeast Montana,” and that his commitment to respecting tribal sovereignty and the rights of U.S. territories “is not lip service.”

Zinke is an avid outdoorsman, and the department’s home page boasts a large photo of him fly-fishing. His Medium post included a photo of him standing outside Glacier National Park with his wife, Lola. On Thursday he wrote about one of his favorite memories hiking on public lands, recalling that he suffered a painful mishap while trying to impress his future wife near the military base in California where he was training to become a Navy SEAL.

“I was trying to show off some rock climbing skills I had just picked up training with the SEAL teams, but lost my hold and I broke my ankle,” he wrote. “I did what any guy would do in my situation: I stood up and kept on hiking, surely messing up my ankle a bit more. Lola and I finished the hike and I didn’t collapse in pain, but the bigger accomplishment was I won Lola’s heart.”

Although Zinke received much more bipartisan support than most of President Trump’s other Cabinet nominees, he also faces challenges mediating between some of Interior’s traditional supporters and conservative Republicans eager to make changes to how public lands are managed. Utah Republicans, for example, have asked Trump to unilaterally revoke national monument status for Bears Ears, a tribal site in southeastern Utah that Obama designated less than a month before leaving office.

Zinke has said that reducing the $12.5 billion backlog in maintenance and operations for national parks is one of his and the president’s top priorities. But it’s unclear how much money the administration can devote to the task and other Interior Department programs, given Trump’s push to boost military funding while cutting other discretionary spending. Interior may face a budget trim of 10 percent to 12 percent, according to individuals briefed on the White House plans. These individuals asked for anonymity because no final funding decision had been made.

In a sign of how contentious lands issues have become, an Instagram post this week by the Interior Department — accompanied with a quote from Zinke — attracted criticism as well as tens of thousands of likes.

“I hope those jobs are filled by people focused on protection and preservation and NOT mining, logging and drilling!” one person wrote. “An attack on the sanctity of our national parks and monuments will face strong resistance!”

Zinke made it clear in his note that he was adamantly opposed to selling off federal lands, as some congressional Republicans had proposed, but he wanted to give Interior employees more flexibility in how they operate.

“We serve the people, not the other way around,” he wrote. “Washington has too much power. I think we need to return it to the front lines.”

More from Energy and Environment:

White House eyes plan to cut EPA staff by one-fifth, eliminating key programs

Humans have caused an explosion of never-before-seen minerals all over the Earth

Antarctic ice has set an unexpected record, and scientists are struggling to figure out why

For more, you can sign up for our weekly newsletter here and follow us on Twitter here.