'Secrets of the Penguins' to be premiered on eve of Earth Day

Years of filming, often in extreme conditions, has provided new insights into the extraordinary challenges endured by penguins for a documentary series to be premiered on Monday, the eve of Earth Day.

"Secrets of the Penguins" is voiced by US actor Blake Lively and hosted by National Geographic explorer Bertie Gregory, who hopes to engage the widest possible audience with the natural world.

He says filming that included 274 days on the Ekström Ice Shelf in Antarctica, home to around 20,000 emperor penguins, as well as in locations from Cape Town in South Africa to the Galapagos Islands, led to discovering "new penguin secrets".

"I have filmed penguins a lot before," he said. "I thought I knew penguins. I was so wrong."

The three-part series, to be screened on Disney+ on Monday, and on Nat Geo Wild from Tuesday, in all took more than two years to film.

The highlights include penguin chicks jumping off a 50-foot ice cliff in order to dive into the sea for the first time in their young lives.

"As soon as the first one went... they all started to jump. It was an amazing moment to witness," Gregory said, adding the exploit has never been broadcast before. "They're the only animal in the world to raise their young during the Antarctic winter. It is the coldest, darkest, windiest place on Earth."

Gregory says the significance goes beyond any one species. "We should want to look after penguins, not just because it makes us feel warm and fuzzy inside, but because we need healthy, wild places for so many things," he said.

The 31-year-old explorer has two Daytime Emmy Awards for the series Animals Up Close with Bertie Gregory and a BAFTA Television Craft Award for shooting British naturalist David Attenborough's Seven Worlds, One Planet.