The Gentoo penguin colonies of Antarctica are not a place for quiet conversation. "My first season down, I was blown away by how loud they were," Maureen Lynch, a doctoral student at Stony Brook University in New York who spends her winters studying the Antarctic birds, told Newsweek. "It's just constant, constant noise."
But somehow, the penguins make sense of the situation, a talent Lynch compares to being able to pick out your best friend's voice across a room full of hundreds or a thousand people talking. That's despite the fact that during breeding season the tuxedoed birds rely on just one type of call for almost all of their communication needs, Lynch says.
"When they make a noise, 99 times out of 100, it is this call," known to scientists as an ecstatic display call, she said.
Lynch has spent four Antarctic summers mounting heavy-duty recorders by penguin nesting sites and collecting audio files of the Gentoos shouting as they incubate their eggs and raise their chicks. Her analysis of that call was published Wednesday morning by the journal The Auk.
The Gentoos penguins take these calls seriously. "It's energy intensive, they have to stand up, you can see their chest heave as they make this call," Lynch says. Sometimes they're clearly communicating with mates, but sometimes they call when no other penguins are around. Sometimes they call when they seem irritated, and sometimes they call when they've just woken up from a nap. Lynch says her analysis is the first step to understanding what the calls actually mean.
Lynch's work was possible because her lab works with a non-profit organization that teams up with cruise ships to give scientists rides around Antarctica, which meant she could record sites across the Gentoo's habitat to look for differences between colonies as well as between individual birds at the same site.
Reseachers already knew the call is what adult penguins use to recognize their mate and what chicks use to recognize their parents, so it makes sense for neighbors to have their own unique version of the call. "It's necessary to sound different from penguins sitting next to you so that your mate can find you," Lynch says.
But it's not clear yet precisely how to parse Gentoo noises. Despite the need to identify other birds correctly to avoid awkward situations, individual birds still vary their calls. And according to a computer program Lynch taught to analyze the recordings, there's no rhyme to the differences that appear across the whole population of penguins. "We do see differences between colonies, but they're not really predictable differences," Lynch says.
Gentoos are particularly interesting to study, Lynch says, because unlike other penguins, they're actually thriving—populations are increasing and they're even settling in new territory. That's intriguing because the birds usually very reliably return to the same mates and nesting sites year after year.
Tracing the penguins' calls could explain how they're moving despite that fidelity. "They are making new colonies, and we don't know how they're doing that," Lynch says.