Last week Colin Roberts tweeted this video from one of his forest trailcams in southwest Scotland. His cameras record the activities of pine martens but the view is sometimes dominated by another species, the Eurasian jay.
Eurasian jays (Garrulus glandarius) are intelligent, curious, and very vocal mimics. This particular jay punctuates his visits with the sounds of a squeaky tree, a tawny owl, and an amazing Star Wars riff.
Then he gets really close to the lens and … oh my!
Now that the birds are singing again and more singers will arrive on migration, it’s time to practice identifying songs by ear. Yes, it’s hard to do but it’s easier if you can visualize the song.
Just like a sheet of music, a spectrogram of bird song shows how the frequency (pitch) goes up and down. The black dashes graph the frequency and length of the notes. The brown wave graphs loudness in decibels.
Play the matching audio to hear the graph: a song sparrow recorded by Ted Floyd, Xeno Canto XC374118.
Two quizzes follow the video or you can try them independently at the Bird Song Hero Challenge. TIP: Watch the sonogram as it plays! Some of them are tricky.
p.s. Did you know that birds sing harmonies we can’t hear? On the song sparrow spectrogram, above, there are tall vertical dashes during the fast part of the song. The bird is harmonizing with himself in the 12,000 HZ frequency. If you’re older than 30-something, you probably can’t hear it.
Golden-crowned kinglets sing an ascending, accelerating series of up to 14 very high-pitched tsee notes lasting up to 3 seconds and sometimes ending in a musical warble that drops an octave or more in pitch. This is one of the first bird songs that people stop being able to hear as they age.
If you can’t hear the kinglets you are probably over age 65, perhaps younger, and probably have age-related hearing loss. Presbycusis affects 1 out of 3 of people by age 65 and half of us by age 75. The CDC explains that “the most important sounds we hear every day are in the 250 to 6,000 Hz range.” Kinglets vocalize around 8,000 HZ.
What are HZ? Sounds cause vibrations and are measured in vibrations per second: 1 Hertz (HZ) is 1 vibration/second. High-pitched sounds vibrate faster than low pitched sounds so “high pitch” is also “high frequency.”
At birth humans can hear sounds from about 20 to 20,000 HZ but we start losing our upper range of hearing at age 18! Most of us don’t miss sounds above 17,000HZ but some teenagers in the UK will. They capitalized on the age-related hearing difference by creating a “mosquito whine” ringtone that teachers cannot hear. See and hear it on NPR.
The kinglets in the video are vocalizing at 7700 to 8400 HZ as shown in this graph from the Spectroid app on my mobile phone. The pink scale at the bottom shows the kinglets singing in the 8000 HZ area (at right) and my voice below 5000 HZ (long pink lines on the left). (Top graph shows loudness in decibels.)
So now I have two ways to see golden-crowned kinglets singing. I can watch their beaks or I can watch the Spectroid graph on my mobile phone.
Perhaps if I point my cellphone in the woods I’d see if any golden-crowned kinglets are out there.
After months of silence, spring is coming and the birds are singing again. It’s the best time of year to practice identifying birds by song.
No matter your skill level there’s always more to learn. If you’re an expert, it’s time to practice songs heard only once a year during spring migration. (Cape May warbler!)
If you’re new to bird song you probably think, “It’s so hard to learn bird song. I don’t know anything!”
Here are two hot tips to help birders at any level.
Tip #1: You’ll learn the song better if you see the bird singing. We humans are visual learners. Look for the unknown singer and watch him sing.
The eastern phoebe pictured above looks plain but he’s easy to identify by song because he says his name: FEE bee! FEE bee! The author of the video below went looking for the bird to watch him sing. It’s a bit seasick-making 😉
Tip #2: Keep at it! You already know some bird songs. Just build from there, one bird at a time.
Here are three birds most people can identify. I bet you can, too.
Have you ever wished for a tool that could accurately identify a single bird’s voice among dozens of singers? You aren’t alone. Ornithologists are eager for a way to census birds using field recordings, but the sheer volume of data and complexity of bird song makes this a daunting task. A free tool that can identify huge volumes of song data doesn’t exist yet, but the Kitzes Lab at the University of Pittsburgh is creating one.
OpenSoundscape uses machine learning, a subset of artificial intelligence (AI), to scan recorded birdsong and algorithmic hunches to arrive at a song’s identity. To do this the Kitzes Lab starts with real life recordings.
The team brings the recorders back to the lab and downloads the sound files to the database. (Some day the software will be able to triangulate GPS from several Audio Moths and determine a single songbird’s location!)
Here’s one recording of at least six individual birds. OpenSoundscape is learning how to identify them.
It makes a spectrogram of the sound file (below), then picks out each pattern and uses algorithms and the classifier library to identify the individual songs.
The more songs it successfully identifies, the better its algorithms become.
By the end of 2019 the OpenSoundscape models, software, and classifier library of birdsong will be ready for researchers on a laptop, cloud service or supercomputer. Ornithologists will be able to gather tons of data in the field and find out who was singing.
p.s. WESA featured this project in their Tech Report on 26 Feb 2019. Click here to listen.
(credits: photo of ovenbird by Aaron Budgor on Flickr, Creative Commons license. Photo of Audio Moth on a desk by Kate St. John. All other photos and sound file, courtesy the Kitzes Lab)
Crows are common in the city but ravens are rare so I was surprised to hear a raven this week in Schenley Park. It called and circled overhead waiting for its companion to arrive. “Brrrock! Brrrock!” When the second raven caught up they flew away together.
I see ravens in town about twice a year but I only hear them make the Brrrock call. If I lived where common ravens (Corvus corax) are common, I’d hear their wide variety of sounds.
This video from Anchorage, Alaska gives you an idea of the ravens’ vocal range. He starts with Brrrock. Then he gets creative.
When you’re vulnerable to predators it pays to stick together and have a good lookout to warn you of danger.
The dusky-throated antshrike (Thamnomanes ardesiacus) doesn’t look important but he’s quick to notice the presence of hawks and falcons and has a distinctive alarm call that wakes up the forest to impending danger. It turns out that he’s key to the foraging location and cohesion of his mixed species flocks in the Amazon.
Early this year, a study by San Francisco State University temporarily removed dusky-throated antshrikes from their mixed species flocks in Peru. They discovered that within hours the flocks left their semi-open mid-story locations for denser parts of the forest. Often the flocks without an antshrike completely dissolved.
What does the alarm call sound like? Is it loud? Does it grab your attention? You bet! Here’s the sound of a worried dusky-throated antshrike:
His role in the flock works so well that the same mix of species sticks together for generations. As San Francisco State Professor Vance Vredenburg remarked, “You come back to the same habitat after 20 years, and the same flocks are using the same areas of the forest.”
We don’t think of swallows as songbirds but indeed they do sing. Our largest swallow, the purple martin (Progne subis), has a unique sound that carries far. With practice, you can recognize their voices even when you can’t see them.
Purple martins nest communally so the best place to learn their song is near a purple martin colony.
In early summer near their nests, you’ll hear songs, creaky rattles and the sound of begging juveniles. (Purple martins vocalizing near their nest, including begging calls of young, from Xeno Canto XC139568 by Russ Wigh)
The throaty, gurgling chirps are unique to purple martins. When you hear it overhead, look for a nearby colony and go see the swallows sing.