Why are birds never out of key when they sing?

In fact, this is not just about birds; almost all creatures that make pleasant sounds (except us) never make a note out of key.

How is this possible?

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    I am listening to Mozart's piano concerto 21. The seagulls outside are not even trying to sing in key. – badjohn Jul 11 '17 at 10:43

Birds don't sing in a key. Keys are human cultural constructions with some basis in physics, but primarily just artful constructions of a sentient mind.

In fact, when you hear a parrot or something similar attempt to mimic human song, it's not nearly as "in key" as even an average human singer would be.

Birdsong only sounds pleasant because you've learned to associate the sound of birdsong with pleasant things. This is clearly not uncommon! But don't confuse "pleasant-sounding" with "in key." They are NOT the same. A babbling brook, I might say, is a pleasant sound--but it's not even something that can be easily defined in pitch.

Now, what you may be hearing are recognizable intervals between notes being sounded by what I'd call a monophonic pitched songbird. It might be possible to interpret groups of these notes as if they were in a key, and in fact some composers are known to do this (see Olivier Messiaen). However, intervals between pairs of notes don't put birdsong into a key, since every next interval is going to imply something totally different. The intervals themselves are probably based on the harmonic series (since that's the easiest way for physics to work), which is a shared root attribute of human cultural tonality, hence why those notes can sounds like they're "in key".

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    A lot of information compressed into small paragraph. I would like to asked thing from top-down. I do not understand by "Birdsong only sounds pleasant because you've learned to associate the sound of birdsong with pleasant things." -- what pleasant things? This line can be used with anything that we say 'we like'. – Quazi Irfan Jun 6 '12 at 3:04
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    I agree - I think the second explanation (namely, that birdsong sounds more or less in key because that's how the physics of sound production and reception works) holds more water, and birdsong with recognizable tones probably sounds pleasant to us because we produce and recognize sound in a similar way. – reinierpost Jun 6 '12 at 5:27
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    Birds tend to only sing in good weather when the sun is shining. This I think is the most important aspect to "associating birdsong with pleasant things". – awe Jun 6 '12 at 6:05
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    I probably could have written 'pleasant feelings' instead of 'pleasant things', that is, typical human beings have developed a positive behavioral response to the sound of birdsong. If a sparrow made the exact same sound but was a gigantic carnivorous beast that ate humans for dinner, you would have developed a negative behavioral response to the same sound. This is basic natural selection, and can be applied to why we think babies are cute, why healthy people are more attractive, and why sweets taste good. – NReilingh Jun 7 '12 at 2:15
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    Re: association: birds only 'sing' when there are no predators around. If there are, birds usually screech and chatter. Veldt evolution in action? Also, if you've aver been around a large mass of birds of the same species all making noise together, you'll know it's not always pleasant. – naught101 Oct 11 '12 at 8:17

Bird song is not tonal. Read this paper by Wallins and Mercer. A key quote from them:

Any similarity between birdsong and modern music is by analogy

And Carol Whaling (document available at the same link) provides this spectral plot:

enter image description here

Which you can see is not tonal, in the way we think of music.

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    I love that graphic. I've never seen better proof that animals have culture than that. Blows my mind. – NReilingh Oct 7 '12 at 4:43

I'm happy to admit that I don't know what I'm talking about on this subject but its my understanding that all creatures that rely to some extent on sonic communication occupy very select frequencies on the global soundscape.

i.e. Elephants use very low bass frequencies to communicate, whales very high frequencies. It depends on the medium in which the animals exist i.e. air or water etc.

Birds themselves communicate on different bandwidths of frequency.

A sparrow for instance communicates sings on a bandwidth that is distinct from say, a magpie. This is so when they all occupy the same space they can differentiate the calls of their own species from that of others i.e. increase the signal to noise ratio.

No doubt their hearing is specifically attuned to these frequencies as well. I'm not saying they're deaf to other frequencies but that their hearing is geared towards a specific range of frequencies as is our own.

So when you ask how is this possible. Evolution no doubt. I'm sure their lyranx or tweeters or whatever you call a birds voice box is engineered to produce certain frequencies in much the same way as tuning a guitar... by tensioning the strings.

In other words its possible because its necessary to survive. If birds couldn't call a mate or hear the cries of their young when in a forest full of different bird species, they'd simply perish.

I don't know when the last time was that you were in a forest but them birds, they sure do make a racket. They're always talking over the top of one another. So without "perfect pitch" they may as well be talking to themselves.

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    Interesting stuff, but it doesn't really answer the question.. – naught101 Oct 11 '12 at 8:55

Please, listen more closely. Modern music is not a standard to decide whether or not birds are musical. They do indeed sing phrases, that have their own mode or key. Listen to finches and warblers at noon during mating season. An important thing to remember about birdsong is that it is EXTREMELY fast. Not only are the phrases being sung in a blisteringly tempo, but the songs are being screamed at the top of their lungs in pure joy. So try slowing down a recording of a bird's mating song, especially the sing songy cockateau, warbler, finch type for an easy example. They are not particularly monophonic, but have two vocal chords, actually. This makes it even harder to determine their pitch, because they are singing two notes at once, and will frequently deploy all sorts of expressive timbre adjustments, as well as distortive effects(a human analogy would be humming while whistling). They may not do an intro, verse, chorus, verse, chorus, outro like modern music, but I'd venture to say they are far better than most human musicians. They all are very individual too, which is most obvious during mating season.


Birds do sing in key with music. I first noticed this 18 or so years ago when I was playing piano and a mourning dove wanted to sing along, would wait until the music got into his register, and he was in key with the passage. Basically the bird is compelled to be in key with the music because he is responding to the vibration. I wondered about this for a couple years, because the more birds I played for the more sang in key with it, and were attracted to the music, but birds also have calls that are not considered songs, and the calls were always in key too, as were the begging calls of their offspring.

I boiled it down to the vibration reaction when one night I was leaving a symphony performance and realized the entire crowd (of humans) leaving the concert hall was talking in key with the last chord the orchestra played. (I have absolute pitch and never found it useful for anything until I was able to make these observations.) Furthermore, the cicadas that "sing" in the trees at the outdoor classical concerts at Ravinia in Highland Park, Illinois, are not just in key with the music but they also know the dynamics of the piece and rise and fall with the orchestra.


Birdsong cannot be 'out of key', since it is not necessarily tonal - any more than (non-tonal) human speech could be said to be out of key. But that does not mean that some birds cannot (sometimes) sing tonally, just as many humans can. I have read the recommended article by Wallins and Mercer, and they do not rule out tonal birdsong. Over the years I have heard many blackbirds (in particular) repeatedly producing (presumably favoured) tonal melodies, using intervals identical to those of a human major or minor scale. Not having absolute pitch myself, I cannot say in what key (or even if an individual bird favoured a particular key), but using tonic solfa, my impressions is of a preference for the notes 'do - mi - so - la - do'.


It seems to me that Birds do not sound out of key or off pitch, what have you, when they sign, because they are higher up in the register where the scale length is getting tighter and it is harder to distinguish off key notes since the intervals are smaller. They have a harmonic overtone and this causes it to be more melodic in the sense that it is more harmonic even though we know melody and harmony are not the same. Reminds me of a story about the Fox and the Crow and the Fox gets the Crow in the Tree to sing for him so that he drops his cheese. Suddenly I feel I may have fallen victim to this very scheme at this very moment as I am trying to sign this tune of why birds have fancy wings.... But I Digress.

Also as pictured in the waveform and frequency response curves the sound consists of a more square or sawtooth type wave than a pure sinusoidal wave which accounts for the chirp.

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    Truth is the birds have no sense of melody and are horribly off key. The randomly improvise with chaotic tweeting and twittering that has no rhythmic sensibility and would not qualify as Chopin. Perhaps that is just me though... No ?? – Daniel Buchanan Nov 16 '13 at 4:18
  • Maybe I should try to test your theory that "they don't sound off-key because they sing so high" by transposing a bird song by an octave or few. – John Dvorak Nov 16 '13 at 4:23
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    If you look at the frequency plots it is quite obvious that this theory doesn't have any basis in fact. It is not more difficult to distinguish off pitch notes (as you can test for yourself by transposing any piece of music up a couple of octaves) – Doktor Mayhem Nov 16 '13 at 12:51
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    @dr mayhem yup, in fact the reverse is true. Pitch distinctions are easier up high. – Some_Guy Oct 31 '16 at 12:45

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