A melodic whistle cuts through the silence. Yılmaz Civelek places two fingers in his mouth and once again chirps into the hilly void. A figure emerges from the green slope, whistles a greeting back and waves — just as Civelek has asked her to.
Civelek is visibly cheered by the response. He is one of just a few people who can communicate using a whistled language (ıslık dili), which locals in Turkey's mountainous Black Sea region call "bird language" because of its similarity to birdsong.
An estimated 10,000 people in the region "speak" the whistled language, which in 2017 was placed on UNESCO's list of intangible cultural heritage that is in danger of dying out.
Words are easily lost in the region, trapped between mountain ridges or carried away by the wind. But a whistle can travel kilometers. No one knows how old "ıslık dili" is, but it's especially favored by sheep herders who need to communicate over vast expanses of land. There are only a few shepherds left. "And then there's technology - the mobile telephone," says Civelek. Despite the geography, it's still possible to get reception in the mountains.
Civelek is from Kuşköy, which translates as "bird village," in the province of Giresun. Like most in his generation, he grew up with the language and doesn't want to see it die out. He is active in a bird language club and plans to share what he knows in a classroom soon.
The 47-year-old, who now lives in the city of Giresun, spends as much time as possible in the high plateau region in the summer. He and his wife have built a small house there, and his sister Muazzez Köçek lives nearby. There are a few cows and a handful of neighbors, but otherwise, only green pastures and dark forests surround the houses.
Köçek is one of the best whistlers in the village. She won best female whistler at Kuşköy's annual bird language festival three times and taken third place in the mixed-gender category five times.
However, she only whistles with her mouth, unlike Civelek, who like most other speakers also uses his fingers. Depending on how far he needs to communicate, he'll sometimes use just his index finger, or several fingers. For distances over five kilometers, he uses his other hand to form a cone that helps the whistle travel farther.
Civelek's son Olcan is less than interested in bird language. The 19-year-old doesn't speak it and also sees no point in learning it. "I don't need it," says the student, who lives in Giresun. He's much more into football, especially his favorite team, Beşiktaş, from Istanbul.
Besides a study that found that people use both sides of their brain when speaking bird language - instead of either the language-dominant left side, or the musically inclined right half
"ıslık dili" has hardly been researched.
Musa Genç, dean of Giresun University's tourism faculty, wants to change that. The 58-year-old, who's originally from the west coast, has made it his mission to protect and research the language.
He wants to offer a language course within three years at the latest and develop a certification program for future teachers such as Civelek.
There's no better place to promote his initiatives than the bird language festival in Kuşköy: people flock there from surrounding villages, the narrow streets fill with cars, the sound of a kemençe lute floats in the air and people perform the traditional horon dance.
"I believe that we must give the bird language a function beyond tradition, so that people say: ‘I need to speak the bird language'," says Genç, after announcing to festivalgoers that he's planning to promote the language to search-and-rescue and emergency services. Otherwise, it'll just become a "show language" and eventually die out, he says.
The language is useful for search-and-rescue services because it can travel long distances - it can help find people who are missing in the mountains, trapped under rubble or lost in caves, says Genc, adding that it could be "life-saving" in such instances.
Civelek remembers a few times in the past when bird language was used in emergencies. When he was a child, he says he used it to instruct dogs to drive off wolves who were attacking herds of sheep and goats he was tending, as well as to warn other shepherds.
He hasn't seen a wolf in a long time now. But not so long ago, Civelek found a goat that had got lost in the high plateaus. So, he chirped out into the distance: "Your goat is here." And then, a tweet came seemingly from nowhere: "Thanks."