King penguins, male-female difference

This 2014 video says about itself:

Just above Antarctica, off the island of South Georgia, lies a breeding hot spot for elephant seals and king penguins known as Gold Harbour.

Filmmaker Richard Sidey captures incredible raw footage and the natural sound of this wild bounty for part of his series, Speechless. “[W]ith the absence of narrative, the viewer is left to create their own narrative and their own experience, without being told what to think … It gives everyone the possibility of seeing these places for what they are without the restrictions of cost and the environmental impact”, he says.

From ScienceDaily:

Distinguishing males from females among king penguins

February 22, 2018

It is difficult to distinguish males from females among King Penguins, but a new Ibis study reveals that King Penguins can be sexed with an accuracy of 100% based on the sex-specific syllable pattern of their vocalisations. Using the beak length, King Penguin individuals can be sexed with an accuracy of 79%.

The new findings may help investigators understand how King Penguins choose mates, and they offer a cost-effective, non-invasive technique for researchers to sex King Penguins in the field.

“The sex-specific syllable pattern in King Penguin calls is a very interesting finding, both from an evolutionary perspective as it is rare in non-passerine species, but also because it allows researchers with very little training to reliably identify the gender of King Penguins without handling the individuals,” said lead author Hannah Kriesell, of the Centre Scientifique de Monaco and the University of Strasbourg.