Animal 'Communication' across Species?

Taxidermied Robotic Northern Pygmy Owl
Jeremy Roberts for The New York Times

In an NYT article, science writer Christopher Solomon reports that "When Birds Squawk, Other Species Seem to Listen" (May 18, 2015), or so he's told by Erick Greene, professor of biology at the University of Montana, who studies animal 'communication.' Professor Greene showed Mr. Solomon what happened when a 'robotic' owl was switched on and began to survey an area for prey:

Greene . . . stepped away from the stand [with the hidden robotic owl] and stood by the home's backdoor. He pressed the fob of a modified garage-door opener. The curtain dropped, unveiling a taxidermied northern pygmy owl. Its robotic head moved from side to side, as if scanning for its next meal. [At that moment, the] yard hushed, then erupted in sound. Soon birds arrived from throughout the neighborhood to ornament the branches of a hawthorn above the mobbed owl and call out yank-yank and chick-a-dee . . . . [Later at] his laboratory on campus, Dr. Greene plugged the recording of the pygmy owl fracas into a computer that he likened to an "acoustic microscope." The calls appeared as a spectrogram - essentially musical notation . . . . One call lasts only a second or three, but can have up to a dozen syllables . . . . [And size matters:] black-capped chickadees embed information about the size of predators into these calls. When faced with a high-threat raptor perched nearby, the birds not only call more frequently, they also attach more dee's to their call. [But not necessarily big size:] Raptors tend to be the biggest threat to birds nearest their own size because they can match the maneuverability of their prey. So a large goshawk might only merit a chick-a-dee-dee from a nimble chickadee, while that little pygmy owl will elicit a chick-a-dee followed by five or even 10 or 12 additional dee syllables . . . . [Moreover,] "squirrels understand 'bird-ese,' and birds understand 'squirrel-ese.'" When red squirrels hear a call announcing a dangerous raptor in the air, or they see such a raptor, they will give calls that are acoustically 'almost identical' to the birds.

I'm not sure what this adds up to so far as animal language in general is concerned, but I am surprised that squirrels mimic bird calls - and vice-versa, I suppose. This article at least shows that some sort of communication is embedded deeply in various 'lower' species, so the possibility that 'higher' species - such as dolphins, orcas, sperm whales, and elephants, not to mention various apes - might engage in relatively complex language is all the more likely.

Why, this might even support the otherwise incredible possibility that human beings can communicate intelligibly, though the preponderance of evidence is much against it.