When whip-poor-wills nest the female lays two eggs on the ground on top of dry leaves, choosing a place where sunlight makes dappled patterns to match her camouflaged plumage. Hall E. Harrison’s Birds’ Nests Field Guide explains:
Incubating bird sits close; when flushed flies silently away like a moth. Eggs usually discovered by accident rather than by search. Friend of author flushed female from 2 eggs, and returning later to point out nest was unable to find it. After careful study, author detected nearly invisible female incubating 4 ft (1.2 m) away.
— Birds’ Nests Petersen Field Guide by Hall E. Harrison
Since they operate at night even a singing male is hard to find. As we approached our cars to leave, a whip-poor-will sounded very close. Barb Griffith found him in the dark, calling from a flat rock. This photo isn’t the bird we saw, but you get the idea.
Even though birds don’t sing in the winter they still make warning calls so a “cheeping” bird should be easy to find, right? Not necessarily.
Some species, like chickadees and white-breasted nuthatches, make sounds that are easy to pinpoint but the calls of others are thin, faint, high notes that are hard to triangulate. Is the bird up or down? To the left or right? In that thicket or the next one?
Here’s a list of winter birds whose warning or contact calls are hard to find. The calls may be insubstantial, but if you recognize the sound you’ll at least know what species is hiding in the bush. (Turn up your speakers.)
For a really narrow high-pitched frequency you can’t beat the three-note contact call of the golden-crowned kinglet. He’s hard to pinpoint even if you can hear him. Now that I’ve lost my upper range of hearing I rely on friends to tell me when this bird is present. The calls are at 7500-8300 Hertz. Can you hear them? Not I!
Don’t feel bad if you can’t find a bird by its warning or contact call. Even if your hearing is perfect some birds are hiding by voice.
(photos by Cris Hamilton and Steve Gosser, see captions)
p.s. Here’s the call of an American robin that means “Danger From The Air.”
In the spring of 2015, Nature On The Go of Green Oak Twp, Michigan found a baby starling fallen from his nest. Since European starlings are invasive, no rehabber would raise the bird for release into the wild, so Nature On The Go decided to raise the starling as an educational ambassador.
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)