Archive for May, 2020

29
May 20

A Magical Musical Bird: The Swainson’s Thrush

Swainson’s Thrush

The whistle came from a thick grove of old growth western hemlocks and Douglas firs. It might have been a tenth of a second long and then was followed immediately by a 2 second upward spirally flourish. It seemed like a flute or maybe an oboe was up in the trees. I stopped dead in my tracks along the dirt road and pointed my parabolic microphone in that direction.

The dense forest where the Swainson’s Thrush Sang.

Three seconds later a much softer whistle opened the tune followed almost immediately by a louder longer one and then a beautiful spirally flourish. The flourish was also a set of over-slurred phrases, each close together and slightly higher than the previous, getting softer as they went. My eyes closed to listen to this Swainson’s Thrush, a one-ounce bird who only recently arrived from his wintering grounds in South America. They breed in the temperate rainforests of Western Washington, and this one was defending its territory and maybe still trying to find a mate.

I’d read that each male has 3 to 7 song types. They vary in their detail and successive songs will be different. I cupped one hand behind an ear to listen closely. The opening whistles seemed to vary in pitch, sometimes one note and sometimes two. The flourishes were so complex and fast that I couldn’t tell how they varied. Maybe the sonograms of my sound recording would help me understand his melody.

The first song of the Swainson’s Thrush on my recording.

The first tune in the sonogram opened with two notes and then the upward spiraling flourish. The second note was louder than the first (as shown by the brighter color on the sonogram) and then the first section of the flourish was loud before it became fainter and went really high in pitch. The opening over-slurred whistles seemed to peak around G6 on the note scale. The first second of the next part went from G6 to G7 to B7 in a series of up and down notes. Then the song became softer and went all the way up to B8 before trailing out for another second around F7. The highest pitches and faint parts I could not hear, but I’m sure the birds could.

The second song by this same Swainson’s Thrush.

The next tune was dramatically different from that first. It opened with a soft up-slurred note and then two over-slurred whistles that were slightly louder before moving into a quicker paced flourish that included a series of over-slurred, up-slurred, and down-slurred notes. The pitch of the entire tune never went as high as the first, only reaching about D8. The next several also appeared a little different from these first two and after six or seven tunes, the bird was clearly repeating itself. 

Above is a Five-Minute Recording of the Swainson’s Thrush singing. The Sonogram of the recording will play as a movie and allow you to see the changing notes. The scale runs from 0 Herts to 10,000 herts.

The songs of Swainson’s Thrushes make my tension float away. These magical musical birds provide a gift of music to our souls.

Swainson’s Thrush
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1
May 20

A Breathtaking Baritone

Stillwater Wildlife Area near Carnation, Washington

Author Note: This trip was done in 2017. As of late April 2020, Washington is in a “Stay at Home” mode as we try to control the coronavirus and the resulting COVID-19 disease. In early May, the state will open some protected areas for recreation while we continue to practice social distancing. If the Stillwater Wildlife Area opens, I hope to make it out early one morning to search for the “pump-er-lunk” bird. An earlier version of this essay appeared in WOSNews 173 in 2-18. I thank Dan Steiffert for letting me use some of his amazing photographs. https://www.flickr.com/photos/danstreiffert/

The trees were just beginning to show a little shape as I inched my way along the dike at Stillwater Wildlife Area. It was 5:00 AM on a Sunday morning in early May, and sunrise would not come for another hour, even longer before the sun hit this area at the western base of the Cascades. My flashlight was off so as to not disturb any wildlife. The songs of American Robins filled the air. Their “cheerily, cheer up, cheer up, cheerily, cheer up” melody proclaimed spring had arrived, and they were ready for another day, even though it looked like night. 

American Bittern – Photo by Dan Streiffert

A different sound made me stop, a gulping like someone was swallowing large mouthfuls of air. It came from the marsh across the small pond to my south. Five gulps were quickly followed by an eerie call: “pump-er-lunk,” then another “pump-er-lunk” and finally, a “dunk-a-doo.” A male American Bittern was trying to woo a female. 

I’d come to record this exact sound, so I settled onto the ground to put my stereo microphone rig on a tripod and see if I could hold still for the next hour. I slid off the gravel-topped dike to station my mic with its back to the bank, partially blocking sounds from behind me. The water was ten feet below, and a few bushes and cottonwoods lined the pond’s edge. Open water extended fifty yards to a thick marsh. The bittern was probably sitting at the water’s edge, hoping a female would like his display. 

Sonogram of the morning chorus at Stillwater Wildlife Area near Carnation Washington. The American Bittern has a deeper call than most birds. They hide in the marsh where this deep call will travel farther through the thick vegetation.

A second male began gulping; he was roughly a hundred yards east of my seat. The closer one instantly responded with his answer. Last week, I was here with a group of birders. The sun had risen as we searched along this old railroad bed, now a hiking trail. One person discovered a male bittern, probably this same one, lurking in the reeds and focused her spotting scope on him. We watched the male contort its neck as it lunged forward to gulp in air, expanding its esophagus like a balloon, and then used that air to make this resonant “pump-er-lunk” sound. 

In five decades of birding, I had never heard their call until last week. They don’t breed in Florida where I lived for more than two decades and were not common breeders near my Maryland home either. The sound last week took me by surprise; I watched the male for a long time while the birding party walked farther down the dike. Every few minutes, the bittern would begin again to blow up his esophagus and bellow out this resonating sound. This behavior and sound were so astonishing that I felt the need to return to see if I could record this spectacular call.

Their courtship boomings have a ventriloquistic nature, and rural people have given them some exciting names; “stake-driver,” “thunder-pumper.”  These are low-frequency sounds that will travel much farther through thick vegetation than the high pitch songs of most birds. Ornithologists think that these calls function both to attract females and tell rival males that this marsh was taken.

American Bittern (adult) Photo by Dan Streiffert

American Bitterns are members of the heron family. Their streaky brown and buff plumage allows them to disappear into the reeds, blending perfectly with the vertical shoots. They often freeze in a pose with their bills pointed skyward, neck stretched, so the streaks in their plumage will run parallel with the reeds. If they see people, they usually sulk back into the marsh.

But on that day, I was alone along this dike; no other person was out this early. I was hunched low; I had headset over my ears; my stereo mic pointed right toward the marsh where the bird just called. My eyes were closed so I could concentrate on absorbing the morning chorus of birds. It was still 45 minutes until sunrise. In addition to the robins, the Red-winged Blackbirds had started their “conk-la-ree” song, and I could imagine them drooping their wings while leaning forward and puffing out their bright red shoulder patches as they bellowed. They reminded me of my high school years when the football jocks would strut down the aisle, not moving aside for anyone, puffing out their shoulders when passing a pretty girl. The six-phrase melody of a Song Sparrow came from right above me. He was probably sitting at the end of a branch, looking across the marsh, and raising his head, puffing out his chest when he sang his beautiful song. Individual male song sparrows have about nine different melodies, and they mix them up in their morning repertoire. He hopes this diversity will impress a mate. 

Juvenile American Bittern (left) being fed by Adult (right) Photo by Dan Streiffert

These birds would be an excellent background to the bittern, creating a musical filler between this heron’s calls in my recording. He’s my quest today. To think a bird could be such a breathtaking baritone. Each time the sound came across the marsh, I was amazed by how these notes were made and wanted to show others this unique love song. Another bittern called to my left, and a third at the limit of my hearing on the right. A long pause happened between their trumpets and then once one started to gulp in air, the others followed. I tried not to move or say anything in spite of my excitement. My recorder picked up every nuance of the morning.

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