Category Archives: Vocalizations

What Are Crows Saying? Listen to the Gaps

Crow cawing (photo by Bennilover via Flickr Creative Commons license)

5 December 2024

Crows are so vocal that we can’t help but think their caws are a language. So what are crows saying in their big boisterous flocks before they roost?

Dr. Douglas Wacker at University of Washington Bothell (UWB) wondered the same thing so in 2017 his team began recording and analyzing pre-roost aggregations on the UWB roofs. The rooftop recordings were not enough to crack the code so now the team has turned to spectrogram analysis.

Dr. Wacker presented information on crow vocalizations at the Olympic Peninsula Audubon Society in November 2024. To measure the calls they analyzed these components.

  • Syllable = a single caw
  • Gap = the length of silence between caws
  • Call = a series of caws
  • Pause = the length of silence between calls
screenshot from Dr. Douglas Wacker presentation to Olympic Peninsula Audubon, Nov 2024

The team recorded crow vocalizations in various contexts and compared the spectrograms. And they discovered an unusual thing. Crows appear to be “saying” things in the silence between their caws (gaps) and the pauses between their calls.

  • Gaps between caws: Are longer in pre-roost aggregations (evening) than in post-roost aggregations (morning).
  • Pauses between calls: Are shorter while mobbing an owl than in pre-roost aggregations.

If you want to know what a crow is saying, listen to their silences.

Crow cawing (photo by Jennifer Aitkens via Flickr Creative Commons license)

Learn more about crow language in this Olympic Peninsula Audubon Society’s video. I have set it to start nearly an hour into the meeting, beginning with spectrogram analysis of crow calls. I’ve included this 15 minute portion here because it is so interesting. Click here to see the entire 1.5 hour meeting.

video embedded from Olympic Peninsula Audubon Society on YouTube. (Starts at 58 mins into the recording)

Some day we might know what this crow is saying. In the meantime, listen to the gaps.

Crow cawing (photo by Jason Hopkins via Flickr Creative Commons license)

p.s. Dr. Wacker described an intriguing idea: The messages in human language come from our sounds. The messages in crow language appear to come from silences. Perhaps we can’t figure out what crows are saying because we aren’t used to listening to the silences.

Playing Music With Birds

28 April 2024

Now that the breeding season is here the air is filled with birdsong from dawn to dusk. Birds sing to claim territory and attract a mate, but they also appear to sing for the joy of joining others in song. Is the dawn chorus actually a community performance?

In the 1920s British cellist Beatrice Harrison discovered that when she played her cello in the garden the birds responded, approached, and sang along.

Europe’s great songster, the common nightingale, was especially drawn to join her performance. (Click here for the nightingale’s song.)

Common nightingale, singing (photo from Wikimedia Commons)

In 1924 the BBC recorded her playing in the garden with a nightingale joining in.

video embedded from Kall48 on YouTube

Fast forward to modern times. Two decades ago in Chicago, musician Lisa Rest lived in a third floor apartment whose windows were level with the tree canopy. On warm days she played her piano with the window open and eventually noticed that birds approached her window and sang while she was practicing.

Because Lisa has perfect pitch she could tell the birds were singing in key with her music. Soon she became interested in birds, continued playing music with them, and started a blog named Goldbird Variations. The birds were especially drawn when she played Bach’s Goldberg Variations.

Read how her journey began at her blog post below or click here to listen to Aria to the Goldberg by Lisa Rest in which she’s accompanied by house sparrow, house finch, white-throated sparrow and northern cardinal.

Nowadays Lisa Rest often goes birding and blogs about birds and the changing seasons. Catch up with her at Goldbird Variations (https://musicbirdblog.com/).

For more information about Beatrice Harrison and the nightingales see The Cello and Nightingale Sessions at publicradio.org.

(credits are in the captions)

Babble, Ring, Toot and Shout

Arrow-marked babblers (photo from Wikimedia Commons)

26 January 2024: Day 8, Hwange National Park, Zimbabwe — Road Scholar Southern Africa Birding Safari. Click here to see (generally) where I am today.

Though I can identify birds by song at home, it’s almost impossible to do in southern Africa among birds I’ve never heard before. To prepare for this trip I spent time learning about the birds I might see. Then I discovered their odd and distinctive sounds. Here’s a sample of some notable ones.

Babble: Arrow-marked babblers (Turdoides jardineii), pictured above, are gregarious birds that nest cooperatively and love to sing together. One or two birds may start the babbling song, then everyone joins in. Even after the cacaphony stops a few will mutter to each other. Babblers are members of the Laughingthrush family (Leiothrichidae). When I listen to them it makes me laugh.


Ring: The tropical boubou or bellshrike (Laniarius major) is a frequent singer with a bell-like voice. Contact calls like bou, houboubou or bobobobo give the bird its name but in song its vocal repertoire really shines. Boubous often duet in male-female pairs or two males in adjacent territories who call-and-respond so quickly that they sound like one bird. The songs are so amazing that I’ve included three examples.

Tropical boubou pair sing a duet at Hwange (photo from Wikimedia Commons)

Toot: The pearl-spotted owlet (Glaucidium perlatum) is the smallest owl in southern Africa, similar in size to our northern saw-whet owl. Though they aren’t in the same genus, the owlet’s call reminds me of a saw-whet’s toot except for this: The owlet toots louder and higher until he drops off at the end.

Pearl-spotted owlet (photo from Wikimedia Commons)

Shout: The hadada ibis (Bostrychia hagedash) is just plain loud. His name comes from his extremely loud and distinctive “haa-haa-haa-de-dah” call which he makes all year long, especially at dawn and dusk. Hadada ibises are now very common in suburbs where people hear them every day. Imagine one shouting from your roof.

Hadada ibis (photo from Wikimedia Commons)
Hadada ibis drying off on a roof after bathing (photo from Wikimedia Commons)

For more sounds of the African bush, including mammals and frogs, see Derek Solomon’s wildlife sound recordings.

p.s. I heard every one of these birds and I saw all except the pearl-spotted owlet. The owlet called from a hiding place just before sunset.

Go Awaaaay! Go Awaaaaay!

Gray go-away bird (photo from Wikimedia Commons)

23 January 2024: Day 5, Zambezi National Park — Road Scholar Southern Africa Birding Safari. Click here to see (generally) where I am today.

Today we’re on a birding drive through Zambezi National Park where we’re sure to hear the unique call of a very plain bird.

The gray go-away bird (Crinifer concolor) is named for the whiny sound he makes that, in English, sounds like “go awaaaaay.” All gray in color, he has a crest like a northern cardinal but he’s more than twice its length and 10 times its weight. Unlike the cardinal’s beautiful song the go-away bird sounds like he’s whining.

In fact he’s making an alarm call and all the birds and animals know it, fleeing or freezing in place while he warns them.

He whines alone …

… or with a crowd.

Gray go-away birds in a thorn tree (photo from Wikimedia Commons)

Go-away birds don’t fly well but they can clamber.

Though their flight is rather slow and laboured, they can cover long distances. Once in the open tree tops however, they can display the agility which is associated with the Musophagidae [Turacos], as they run along tree limbs and jump from branch to branch. They can form groups and parties numbering even 20 to 30 that move about in search of fruit and insects near the tree tops.

Wikipedia: grey go-away bird

At some point I’m sure they’ll tell us to “Go Awaaaay!”

Cheep and Chip, Tock or Knock

Chipmunk with full cheeks,  Cap Tourmente NWA, Canada (photo from Wikimedia Commons)

1 October 2023

Fall migration has been intense over Pittsburgh lately and promises to be excellent tonight and tomorrow as well. Yesterday morning I went birding at Frick Park, expecting to find loads of warblers. No such luck. The birds flew over without stopping. However, for chipmunks it was a fantastic day.

Despite the current warm weather, chipmunks (Tamias striatus) are frantically gathering food to store in their underground burrows where they’ll spend the winter. Since they can’t use their paws to carry food, they fill their enormous cheek pouches.

What could possibly make their cheeks so fat? How about acorns?

Chipmunk stuffing an acorn in his cheek (photo from Wikimedia Commons)

With so many chipmunks scurrying in autumn, you rarely see two together. Chipmunks are antisocial but they like to make calls to warn each other of predators. Among their most common calls are two kinds of warnings.

Cheep or Chip: “Danger from the ground!” This call sounds almost like a bird and warns of nearby terrestrial predators such as a cat, fox, coyote or raccoon.

video embedded from @MarkCz on YouTube

Tock or Knock: “Danger from the air! I see a hawk!” This is a useful call for birders that tells us to search for a hawk nearby. However, chipmunks know that hawks fly rapidly through the forest so all of them take up the call, far and wide, even though the hawk is not near them. Tock! Tock! Tock! Where is that hawk? Erf!

video embedded from Mybackyardbirding on YouTube

Read more about the chipmunk’s calls at North American Nature: What Sounds Does a Chipmunk Make?

(credits are in the captions)

The Calm Before The Crows

Fish crows at Red Hook, NY (photo from Wikimedia Commons)

30 August 2023

In August in the East End of Pittsburgh we get a taste of November dusk. It isn’t the weather or the clouds or the time of sunset. It’s a flock of more than 100 crows, a hint of the thousands to come this fall, that gather on rooftops along Neville Street before flying west to roost.

This year in early August the crows were absolutely silent but as the month progressed a few spoke out, telling me they were in a mixed flock of American and fish crows. American crows (Corvus brachyrhyncos) say “Caw.” Fish crows say a nasal “Uh-oh” (Corvus ossifragus). It’s the only reliable way to tell them apart.

American crow: “Caw Caw Caw.”

Fish Crow: Nasal “Uh oh”

video by Sayre Nature HD on YouTube

I wanted to count by species but the crows remained silent and unidentifiable through most of the month. I tried to tell them apart by sight but my focus on appearance made it impossible to count. So I stop trying. My August eBird checklists place all of them as “American crows” with an X for “Fish crows present.”

Then suddenly last Saturday they were all “talking” and about three quarters of them were fish crows. The flock continued on Sunday evening but I was too busy to count. I shouldn’t have assumed they’d be here on Monday. They were gone and they haven’t been back.

The big flocks will arrive in late October, comprised of 90+% American crows.

For now we’re in the Calm Before The Crows.

p.s. eBird’s Fish Crow Weekly Abundance map shows a dot in Pittsburgh in the month of August … and then it’s gone. Watch the animation here.

(credits are in the captions)

Who’s Singing Now?

Song sparrow singing in August (photo from Wikimedia Commons)

27 July 2023

In late July, who’s singing now?

Almost no one.

Birds sing during the breeding season to claim territory and attract mates but most songbirds wrap up the breeding season by mid-July. When breeding’s over they stop singing.

You’ll hear a handful of exceptions, though, among songbirds who nest many times each year. Song sparrows and northern cardinals raise multiple broods and have active nests in late July. Both are still singing though not as vigorously.

You won’t hear songs from birds who have finished breeding but you will hear their contact calls. Common grackles raise only one brood per year and by July they are already in flocks, sweeping through the woods and foraging on the ground.

Common grackle in flight (photo from Wikimedia Commons)

You might not see them on the shady forest floor but you’ll hear them making “chucking” sounds like this. (Note: There are additional birds making noise in the background of this recording.)

Birdsong will drop off completely next month. Take note of the few singers now.

(photo from Wikimedia Commons; click on the link to see the original)

What’s He Say?

Northern mockingbird on a wire (photo from Wikimedia Commons)

1 June 2023

Northern mockingbirds (Mimus polyglottos) are famous for mimicking the voices of other birds. Often they’re so good at it that the only way to recognize they’re mockingbirds is to notice that the phrases are repeated three times, then a pause.

On Tuesday 30 May I encountered a mockingbird singing his heart out atop a light post at CMU’s Morewood parking lot. He was so excited that he jumped up and down with his wings open. “Look at me!”

Just for yuks I turned on Merlin sound ID to see how the app would process his song. Sometimes Merlin said “northern mockingbird,” sometimes it said the bird he was mimicking.

In the following 2:49 minutes he’s the only bird singing.

What’s he say? Who is he mimicking? Leave a comment with your answer.

UPDATE: Check the comments for my list of songs that I *think* he sang.

(photo from Wikimedia Commons, audio by Kate St. John embedded from xeno canto)

All The Orchard Orioles Sing

Orchard oriole singing at Frick Park, 26 April 2023 (photo by Charity Kheshgi)

9 May 2023

This year the orchard orioles, smallest of the blackbirds (Icterids), returned to Pittsburgh in late April. We knew they were back when we heard this male singing near Frick Park’s Nine Mile Run boardwalk on 26 April. Ten days later we returned to the boardwalk and heard him again but it was a different bird — an immature male — and we remembered this: You can’t assume the singing bird is an adult male. In fact in the spring all the orchard orioles sing.

Orchard orioles (Icterus spurius) spend most of their lives in Central and South America and only a short time on their breeding grounds in southwestern PA from late April to August/September.

Orchard oriole range map from eBird Science

Adult males start singing in Central America before they head north. When they get here they sing during the nesting season and continue while feeding young. Then they fall silent. May is the best time to hear them.

Adult male voices are wiry and rapid with no pattern to the song. Here are two examples:

Orchard Oriole (Icterus spurius) · song Eric DeFonso, Xeno Canto XC792284
Orchard Oriole (Icterus spurius) · song Eric Zawatski Xeno Canto XC559298

Immature males sing, too.

Immature male orchard oriole (photo by Donna Foyle)

One-year-old males look different than adults and to a discerning listener — the female orchard oriole — they also sound different. Singing is a learning process and these yellow-green guys with black faces aren’t accomplished songsters yet. Here are two examples of immature male songs.

Orchard Oriole (Icterus spurius) · song Matthew L. Brady, Xeno Canto, XC781951
Orchard Oriole (Icterus spurius)” by Sue Riffe, Xeno Canto, XC680711

Females sing as well. Birds of the World explains: “Most tropical icterids have a female song and, ancestrally, the whole family is thought to have this behavior. Female Orchard Orioles sing throughout the breeding period with songs that are structurally distinct from those of males. … Their songs are statistically different in 5 of 8 acoustic variables (full song duration, syllable duration, maximum frequency, bandwidth and percent pause), and are easily distinguished by ear in the field.”

Click on the screenshot of the female below to watch and hear her sing.

Screenshot from video of female orchard oriole singing, Macaulay Library ML 238170941

So just when you think that singing bird is male, remember there are species in which all of them sing.

Read more the orchard oriole at All About Birds.

(photos by Charity Kheshgi and Donna Foyle, range map from eBird, female oriole screenshot from Macaulay Library; click on the caption links for further details)

How Plain-Tailed Wrens Sing The Perfect Duet

Plain-tailed wren at banding station, Bellavista, Pichincha, Ecuador, 2011 (photo from Wikimedia Commons)

26 April 2023

Eighty days ago at Ecuador’s Bellavista Cloud Forest Reserve our tour group heard this species singing from a thicket and added him — or perhaps a pair of them — to our Life Lists.

The plain-tailed wren (Pheugopedius euophrys) is hard to see but its incredibly loud voice is easy to hear, made doubly loud when a pair sings a complicated duet. The duet below was recorded near Tandayapa, Ecuador, perhaps at Bellavista, while other birds were singing in the background. The plain-tailed wrens drown them out.

Intrigued by the birds’ fast-paced, precise duet, researchers in 2021 studied the birds’ brain waves to find the signal that governed the interchange. Instead of an added signal they discovered that, “the species synchronizes their frenetically paced duets by inhibiting the song-making regions of their partner’s brain as they exchange phrases.” The listener’s brain hears something from the partner that mutes his/her own song-making at just the right moment.

“Think of these birds like jazz singers,” said lead author Melissa Coleman. “Duetting wrens have a rough song structure planned before they sing, but as the song evolves, they must rapidly coordinate by receiving constant input from their counterpart.

“What we expected to find was a highly active set of specialized neurons that coordinate this turn-taking, but instead what we found is that hearing each other actually causes inhibition of those neurons—that’s the key regulating the incredible timing between the two.”

It’s not too far-flung to think of these birds as jazz singers. “There are similar brain circuits in humans that are involved in learning and coordinating vocalizations. [Lead authors] Fortune and Coleman say the results offer a fresh look into how the brains of humans and other cooperating animals use sensory cues to act in concert with each other” just like jazz singers.

Here’s one more duet from Tandayapa, Ecuador. Amazing.

Read more at Good News Network: Duetting Songbirds ‘Mute’ the Musical Mind of Their Partner to Stay in Sync, Researchers Find. (quotes above are from this article.)

See the original study at PNAS: Neurophysiological coordination of duet singing.

(photo from Wikimedia Commons, audio embedded from Xeno Canto; click on the links to see the originals)