Dawn Chorus Update #8: Fun with Spectrograms at Silver Lake (and on the East Coast)

[Stephen Chase]

Hi Whatcom Birds,

I woke up this morning a little later than I had hoped, and so missed the moment of first light at my dawn chorus destination at Silver Lake County Park. No matter - the chorus was active on my arrival at 5:13am, and the birdlife was phenomenal! Our next batch of neotropical migrants have arrived right on time, including Western Tanagers, Black-headed Grosbeaks, Warbling Vireos, Swainson's Thrushes, and MacGillivray's Warblers. The diversity today was top-notch: 51 species, most of which were passerines!

Today I'll stray a bit from the specific focus on the dawn chorus, because I'd like to chat about the fascinating world of spectrograms. Spectrograms (sometimes also called sonograms) are visual representations of sound. For example, here's a Pugetensis White-crowned Sparrow song - recorded on my walk this morning - in spectrogram format:

The concept is fairly simple. The vertical Y axis shows frequency, with lower sounds at the bottom and higher sounds at the top. The horizontal X axis shows time. The gray "noise" is undesirable - in this case it was just a slight breeze. Water, wind, or a passing airplane or car all bring noise, reducing the visual "pop" of the spectrogram - and of course making the sound harder to hear. In this clip, that gray noise is actually fairly minimal; you can hear the White-crowned Sparrow loud and clear in my original audio clip. I've uploaded six spectrograms to my eBird checklist for today's dawn chorus walk at Silver Lake, including a minute-long clip of the dawn chorus. Have a listen!

I've got to admit, I find spectrograms absolutely beautiful! For one, they provide a "signature" of the distinctive song of each species, and sometimes even of an individual bird's unique song (especially Song Sparrows!). Another name for "spectrogram" is "voiceprint" because the image shows a fingerprint of the bird's song. I love how spectrograms show how distinctive bird songs actually are, especially for birds which otherwise might sound similar. In fact, this is how the popular Merlin Bird ID app works: it converts audio into spectrograms, and then makes a suggested ID based on the frequency and duration of the visual image. I also love how spectrograms give the eyes a match for what the ears hear. I've been out of town on the East Coast for the past week. Take a listen to this stunning Wood Thrush clip I recorded Monday morning in the Blue Ridge Mountains of southern Pennsylvania. Isn't it cool how each rendition of the thrush's song is slightly different both to the eyes and to the ears? Isn't it incredible to see a visual representation of the famous two-membrane voice box of Wood Thrushes! Don't mind me while I geek out for a bit!

Another favorite from my trip east is this accidental duet between a Northern Parula and a Northern House Wren. It's almost like the two were trying to align their songs, but just couldn't quite do it! And here's a Gray Catbird recorded in the Piedmont region of northern Virginia, showing off with its jazzy series of whistles, squeaks, and gurgles. So cool!

I've received a lot of positive feedback from this community about my dawn chorus series; thanks for letting me know you're enjoying these writeups. A couple of you shared that you've been inspired to try out some bird audio yourself. Feel free to share links to your favorite recordings! For those interested in trying out spectrograms for themselves, I'll copy my postscript from a previous writeup below.

Such a fun time of year, isn't it!?

In Everson,

Stephen

*Interested in recording bird songs? The pros use parabolic recording dishes, but it's surprisingly easy to produce high-quality audio clips with a Smartphone. I recommend recording with a dedicated app such as Voice Record. Smartphones have several mics; the one you'll be recording from is on the bottom of the device. When recording, point the bottom of your phone toward the audio source. Avoid recording over nearby noises, such as creeks, roadways, and wind - and beware of your own shuffling and breathing! On a computer, import your recording into an audio editing program such as Audacity, normalize to -3, and trim the clip. Then export to your preferred file type; eBird prefers .WAV. If you upload to eBird's citizen science database (the Macaulay Library), you'll see a beautiful spectrogram of the audio clip as shown above. If you want more detailed instructions, let me know. Enjoy!