Speaker 1: Welcome to brain Stuff from how stuff works, Hey, brain Stuff,
Speaker 1: Lauren Vogel bomb Here. A good birdwatcher can identify the
Speaker 1: local species not just by sight, but also by sound.
Speaker 1: It's something the Audubon Society calls birding by ear. With
Speaker 1: practice and a good field guide, avian enthusiasts learned to
Speaker 1: recognize the trademark tweets, cheeps, and hoots that various birds omit.
Speaker 1: Mastering this skill requires a basic understanding of how and
Speaker 1: why are feathered friends communicate. Often, a given species will
Speaker 1: use its own distinctive set of sounds, like mating calls
Speaker 1: and territorial threats to get assorted points across. Take the
Speaker 1: rock pigeon. These guys cord each other with gentle coups
Speaker 1: and too signal distress. They use a harsh grunt. If
Speaker 1: an individual rock pigeon is to survive and procreate, it
Speaker 1: must be able to recognize both vocalizations. But do what
Speaker 1: pigeons noises mean anything to passing crows or cardinals? Can
Speaker 1: birds understand the calls made by other species? We recently
Speaker 1: discussed this topic with Robert de McGrath, an ornithologist and
Speaker 1: behavioral ecologist at the Australian National University. McGrath has co
Speaker 1: authored multiple studies about interspecies communication in birds. Much of
Speaker 1: his research has dealt with avian alarm calls. These are
Speaker 1: the warning cries that birds send out when a predator
Speaker 1: is cited. As McGrath tells us via email, just about
Speaker 1: every bird species we have studied locally respond to other
Speaker 1: species alarm calls, and we suspect eavesdropping on other species
Speaker 1: calls is widespread around the globe. Perhaps this is not surprising,
Speaker 1: given that almost all species are vulnerable to predators and
Speaker 1: so should use any available cues that predators are around.
Speaker 1: One good example of this phenomenon can be found in
Speaker 1: the relationship between black capped chicken eas and redbreast a nuthatches.
Speaker 1: The two songbirds have much in common. Both species are
Speaker 1: indigenous to North America and attain similar sizes. They're also
Speaker 1: a wary of raptors. When chicken ees see a gosshawk
Speaker 1: owl or some other winged predator, the birds issue an
Speaker 1: alarm call. Like the t s A, their warnings recognize
Speaker 1: different threat levels. High pitched seat calls are used to
Speaker 1: tip off other birds about a raptor that's flying far overhead.
Speaker 1: The eponymous chickend e d cry rings out whenever a
Speaker 1: perched raptor is seen nearby. Extra d s are added
Speaker 1: if a killer looks especially dangerous. Research has shown that
Speaker 1: other birds, like red breasted nuthatches, understand the chicken eese warnings,
Speaker 1: and with close listening, they can decode the exact degree
Speaker 1: of danger that's being advertised in these alarm calls. Clearly,
Speaker 1: eavesdropping has its benefits. Alarm calls can even trigger a
Speaker 1: response from non avian listeners. The tough to tipmouse, for example,
Speaker 1: is a songbird whose anti raptor warning cries send squirrels
Speaker 1: and chipmunks running amazingly. These mammals are known to spread
Speaker 1: the distress signal by imitating it with their own voices. Sparrows, cardinals,
Speaker 1: and jays will also mimic the tipmouse's signature alarm call. Thus,
Speaker 1: an interspecies chorus heralds the arrival of an oncoming threat. Okay,
Speaker 1: so do birds just have an innate understanding of other
Speaker 1: species alarm calls or do they pick up the skill
Speaker 1: over time? McGraph says that at least in some cases,
Speaker 1: certain birds actively learn to identify the cries, superb very
Speaker 1: wrens are a common sight on the Australian National University
Speaker 1: campus in Canberra. As it happens, the school grounds also
Speaker 1: received plenty of visits from a gray bird known as
Speaker 1: the noisy inner. According to McGrath, there's a botanical garden
Speaker 1: across the street where the wrens like to hang out,
Speaker 1: but the miners avoid it. In one of his studies,
Speaker 1: he was able to demonstrate that superb fairy wrens who
Speaker 1: lived on campus fled when a recording of minor alarm
Speaker 1: calls was played. However, the wrens at the botanical garden,
Speaker 1: where again no miners are present, did not react to
Speaker 1: the same recording. This strongly suggests that interspecies call recognition
Speaker 1: is an't innate, it has to be learned. McGrath notes
Speaker 1: we've subsequently even trained fairy wrens to recognize novel sounds
Speaker 1: as alarm calls by pairing them with the presentation of
Speaker 1: gliding hawk models, which unequivocally shows learning Alarm calls aren't
Speaker 1: the only vocalizations that can transcend species. It's common for
Speaker 1: birds to recognize other birds species sounds if there's some
Speaker 1: benefit to recognition. McGrath said. Some species defend territories against
Speaker 1: members of others species and respond to their territorial song.
Speaker 1: Others can recognize contact calls, which helps them form mixed
Speaker 1: species flocks and find food. And then there's the cuckoo
Speaker 1: and notorious brewed parasite. Females lay their eggs in the
Speaker 1: nests of other birds, who are then sometimes tricked into
Speaker 1: raising the cuckoo's chicks to pull off the charade. Baby
Speaker 1: cuckoos imitate the begging cries made by infants of the
Speaker 1: host's own species, but these sorts of imitable cries aren't
Speaker 1: made by single species alone, like chicken ee. The name
Speaker 1: cucka Bara is on Amano Peak. It's derived from the
Speaker 1: world famous cackle made by these birds. Hollywood seems obsessed
Speaker 1: with their exotic laugh. Cucka Bara cries can be heard
Speaker 1: in the background of such films as Raiders Have Lost Arc,
Speaker 1: The Naked Gun, and assorted Tarzan movies. Today's episode was
Speaker 1: written by Mark Mancini and preduced by Tyler Clang. For
Speaker 1: more on this and lots of other barrier busting topics,
Speaker 1: visit our home planet how Stuff Works dot com.