<\/a>Doug Wacker walks a Fairbanks road last fall while pursuing ravens, the voices of which he is recording.(Courtesy Photo \/ Kim Wacker)<\/p><\/div>\n\t\t\t\t
Many of Wacker’s recordings are the voices of members of the greatest local congregation of ravens he has found so far — at the Fairbanks dump.<\/p>\n\t\t\t\t
“I never thought I would go do an academic sabbatical in a landfill,” Wacker said during a recent presentation.<\/p>\n\t\t\t\t
Wacker wonders if there is any pattern in the array of sounds that come from a raven’s mouth. Over the years, researchers have identified up to 116 different vocalizations from ravens.<\/p>\n\t\t\t\t
Though scientists who study ravens have debated that number, William Boarman and Bernd Heinrich described a few types of specific calls in a raven description they wrote for the Cornell Lab of Ornithology’s Birds of North America. The distinct calls were begging, vocal play, predatory alarms, demonstrative calls, knocking, comfort sounds, chase calls and mimicry.<\/p>\n\t\t\t\t
Wacker is now recording the sounds of ravens (and their cohorts bald eagles) at the Fairbanks landfill 24 hours a day. He is also recording at many other places opportunistically.<\/p>\n\t\t\t\t
Wacker wants to further decode raven calls using machine learning, which he describes as using a computer to look for patterns.<\/p>\n\t\t\t\t
He said humans are biased in their descriptions of sounds, noting that scientists have described the same call ravens use to announce they have found food as an aw, a kow, a ky and as a yell.<\/p>\n\t\t\t\t
“We’re all calling the same (sound) something different,” Wacker said.<\/p>\n\t\t\t\t