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Night songs from springtime birds

  • A yellow-billed cuckoo. PHOTO BY JENN GOELLNITZ

For the Ledger-Transcript
Published: 5/4/2020 4:48:22 PM

How are you getting through the pandemic? Some folks are knitting. Others are doing jigsaw puzzles. My wife has become a crossword junkie. Then there is the sourdough bread craze. I’ve found something a little different.

Most of our birds migrate under the cover of darkness to avoid hawks and use the stars for navigation. Occasionally you can spot one with a telescope as it passes across the face of the moon, but the best way to experience bird migration is to see with your ears. On active nights, birds are so numerous that they are picked up by Doppler radar. You can even hear them as they pass overhead. At dusk, I put a microphone and recorder out on my deck to record the nocturnal bird migration. The next morning, I retrieve the gear and check for messages. Then I have to figure out who left which message. It’s like a jigsaw puzzle for the ears.

Since I started recording in mid-March, many hundreds of individuals have left voicemails, including Wood Duck, Virginia Rail, Killdeer, Ring-billed Gull, American Bittern, Great Blue Heron, Hermit Thrush, American Robin, Chipping Sparrow, Field Sparrow, Dark-eyed Junco, White-throated Sparrow, Song Sparrow, Rusty Blackbird, Louisiana Waterthrush. It’s a wonderful way to experience the breadth of bird migration in real time.

Nocturnal flight calls are not your typical bird vocalizations. They are thought to be a means by which birds stick together, helping to keep otherwise wayward individuals on the correct course heading, especially during periods of reduced visibility. Some species like cuckoos have a distinctive nocturnal call note, which is difficult to confuse with any other nocturnal sound. Other species, notably many sparrows and warblers can be trickier for the human ear to parse. In these cases we can enlist the help of technology by uploading a recording to audio editing software to be displayed as a spectrogram. These are graphic representations of sound that plot frequency against time, rendering otherwise identical sounds distinct from one another. There is even a field guide for spectgrams if you want to get down in the weeds. But identification and analysis is secondary. It’s important to recognize that we don’t need to know why birds sing to appreciate the song. We don’t need to graph species per hour to be spellbound for life. Peak migration in New Hampshire happens during the second week of May. No fancy equipment needed. Just step outside about an hour after dusk, cup your hands to your ears, look to the heavens and try to listen in on one of the most marvelous natural events that this wonderful world has to offer. At least that’s how I’m getting through the pandemic.

Check in for regular updates on the nocturnal migration at harriscenter.org/nightsongs. Cornell University hosts a bird migration forecasting service at birdcast.info, which will help you to pick the right night to listen.

Eric Masterson is Land Program Manager at the Harris Center For Conservation Education in Hancock.




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