The prince, 32, helps host one of his favorite charities at a bash at Windsor Castle

By Simon Perry
May 21, 2015 06:40 PM

Prince William dusted off his tuxedo and black bowtie and raised a glass to one of his favorite charities at Windsor Castle on Thursday evening.

The prince, 32, was partying solo – without wife Kate, 33 – but he was surrounded by friends as he led the celebration for conservation charity Tusk Trust at his grandmother Queen Elizabeth‘s castle, about 30 miles west of London.

The elegant bash is part of a week of engagements that has seen William hand out awards on behalf of the Queen, meet England’s women’s soccer team and check in on the work of his other key cause, United for Wildlife.

The party, which was held in the magnificent St. George’s Hall and attended by 300 guests, including mezzo-soprano Katherine Jenkins and British comedian Rory Bremner, was extra special because it marked the 25th anniversary of the Tusk Trust.

Conservation is one of the key causes William has spent much of his post-military life focusing on, especially with the launch of United for Wildlife in 2014. And he’s sharing his passion for wildlife with his children – Prince George’s nursery is African-themed.

“I’ll have toy elephants and rhinos around the room,” William told CNN in 2013. “We’ll cover it in, you know, lots of bushes and things like that. [We’ll] make him grow up as if he’s in the bush.”

William told the guests that the charity is as much about helping “the great charismatic animals that roam Africa – the elephants, rhino, lions and so on – as it is the people of Africa, who must be cared for too. And Tusk spoke for both the people and the wildlife when it recognized that one group flourishes only when the other does.”

“I am hugely proud to be Royal Patron of Tusk Trust, a position I’ve now had for 10 years – longer than any other position I’ve held bar none,” he added.

The prince praised how the charity, led by CEO Charlie Mayhew, has raised “25 million pounds [$39 million] in 25 years in support of over 100 projects, protecting 36 different endangered and critically endangered species.”

It has also built and refurbished 30 schools, now attended by over 72,000 children, and supported 450 game guards in 30 conservancies.

With guests from Tusk USA and others from around the world, he was hoping for increased fundraising at the birthday bash.

Special wine vintages, William joked, had been chosen “that encourage generous donations, so please don’t prove them wrong.”

After dinner there were performances by Jenkins and Bremner.

William is set to spend the next week off with Kate, 33, and their young family, until he returns to his new job as an air ambulance pilot on June 1.