Thomas Bancroft; The Swainson’s Thrush

Thomas Bancroft visited earlier this year in April during a time when our forests are full of song and sightings of Swainson’s Thrush, a bird that arrives at this time of year during their northward migration. Here is a link to a sound recording of this species in our forests along with a beautiful essay he wrote about this bird. Enjoy!

tombancroft

A Swainson’s Thrush in Panama
By Thomas Bancroft

The flute-like whistle began an upward spiral but then appeared to stumble. The bird started again and continued to misstep before reaching the ending that was familiar to my ears. It sounded like a person trying to remember a tune, knowing he knew it, but also knowing he still didn’t have it quite right, so the practicing continued. Finally, the full Swainson’s thrush song burst through the woods.
But, there I stood in a montane forest in Western Panama thousands of miles from this bird’s breeding range. It was late afternoon on an early April day, and I had hiked up the Rio Colorado valley in Chiriquí. All day, the woods had been full of the chip notes of hundreds of Swainson’s thrushes, and I had seen at least half a dozen individuals as they flitted through the understory. This was a thick tropical forest of broad-leaf trees, not the coniferous forests where this species breeds in North America. Bromeliads and orchids clung to many branches as well as dense blankets of mosses and ferns.
According to Jeffrey, this species had only arrived in the Mt. Totumas area in the last week, and individuals would be abundant throughout April, fattening on fruit and insects before their next leg north. They winter in northern South America — Colombia, Ecuador, Peru, and Venezuela — and were heading north to breed in the western United States and Canada. Ornithologists think that northbound Swainson’s thrushes can average 250 km during one of their nightly migration flights. After dark, the urge to fly north may overtake them, and they travel for as long as their fat reserves, their tank of gas, will last. They migrate at an altitude of a few hundred feet to six thousand, depending on wind, cloud, and fog, often giving their chip notes as they go.
The thrush I was listening to finally had his song down pat and was singing variations of it every few seconds. I remembered the first time I heard this magnificent song. I was in high school, and my sister and I were hiking in the mountains of western Montana. The melody seemed to float out of the dense forest and wrap around us. The valley in Montana had thick conifers, Douglas firs, western hemlocks, and red cedars. Those wet temperate forests were so different from this exotic tropical place where I was hiking in Panama.
By early May, the quickest migrants will arrive in the Pacific Northwest where I now live, and by early June, their numbers will peak as they start their breeding season. Swainson’s thrushes weigh about an ounce or approximately half a serving of dried wild rice. Yet, they can make this almost 5,000-mile journey on their own. It might take them 30-night flights to reach my home in Seattle and even more to arrive at the northern ends of their breeding range in Alaska. They orient themselves by the stars, earth’s magnetism, and the location of the sun in the evening and morning. All these travels are done through internal knowledge.
I stared into the forest, listening to that wafting, ethereal and rich flute, and thinking there was no way I could make it home from here on my own. I’d planned to stay a week and then take a taxi back to the airport and a series of flights to reach Seattle. Along the way, someone else would guide me, feed me, and point me in the right direction. The notes seemed to penetrate the forest, graceful, lucid, poetic.

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