The varied thrush is a rare visitor from the West Coast. It's a bird that breeds in California, Oregon, Washington, Alaska, and the Canadian provinces of British Columbia and Yukon. What's it doing in Pennsylvania, you might ask? Each year about this time there is a small spattering of varied thrushes that show up in the Eastern United States, mostly reported around the Great Lakes and the Northeast states. It's also true that its not every year that varied thrush sightings are reported in Pennsylvania.
Where did this Wild Neighbor come from, and what brought it here?
It must have come from north-west North America; it's breeding range.
I did a little research on eBird.org, the Cornell Lab of Ornithology's global bird sightings database. Keep in mind it is very possible for a western bird to make it to the east coast and back without ever being detected. That being said, I've placed three flight paths across the United States that are informed by recent eBird sightings which show potential routes that this particular varied thrush may have taken to get to Tioga County, Pennsylvania.
|Yellow dots on the left indicate potential breeding terriories. Black, blue, and brown lines are potential flight paths. Yellow dot in PA is location where the varied thrush showed up today.|
Another question is, when did this particular varied thrush begin its eastward journey? Was it a relatively slow migration that occurred over the course of several weeks or even a month? Or was it a very rapid migration that took a week or less?
Looking at recent weather patterns, one scenario is that our varied thrush rode the front of Winter Storm Ezekiel. Imagine a varied thrush being carried by the strong winds of a winter storm front while reading this recap of Ezekiel from weather.com:
"As this intense storm approached the coasts of southwestern Oregon and northwestern California last Tuesday evening, Nov. 26, it underwent bombogenesis. The storm's minimum central pressure dropped 43 millibars in 24 hours, far exceeding the criteria of 24 millibars within 24 hours to be deemed a bomb cyclone. Tuesday night, the pressure dipped to at least 973.4 millibars in Crescent City, California, as Ezekiel made landfall. This value was an unofficial all-time record for the lowest sea-level pressure observed anywhere in the state of California, according to the National Weather Service office in Eureka. Cape Blanco, Oregon – the notoriously windy spot on the Pacific Northwest coast – recorded a sustained wind of 85 mph with a gust to 106 mph early Tuesday afternoon. Winter Storm Ezekiel first entered the West Coast last Tuesday, Nov. 26, when it hit southern Oregon and northwestern California as a bomb cyclone. The storm then moved slowly eastward across the West, Plains and upper Midwest Nov. 27-30, spreading snow and strong winds through parts of those regions. Snow, freezing rain and sleet spread into the Northeast Dec. 1-2."
(following Winter Storm Ezekiel. https://weather.com/storms/winter/news/2019-12-01-northeast-great-lakes-snowstorm-forecast-ezekiel)
I, for one enjoy the thought of a varied thrush riding the winds of a wicked-strong winter storm as it makes its way across North America. One theory among many possibilities.
Where did you come from? How did you get here? I ponder these questions while watching you, tucked neatly within the snow-laden branches of an Eastern hemlock tree at the forest edge. You seem to me patient as you wait your turn at the feeding station. Chickadees, titmice, and juncos in a flurry. A few of them depart. Now alighted on a wire overlooking all, but not for long. A few quick steps and a vigorous scratch on the snow-covered yard and one, two, three black-oil sunflower seeds fill your gizzard. I see the full beauty of your plumage. burnt-orange lines and breast on slaty face and body. A visit from the north-west coast you are a treasure to behold.
Thanks to the kindness of a friend and the hospitality of his neighbor I was given a great gift to be able to witness this living treasure right here in north-central Pennsylvania 10 minutes from home.
|Varied thrush next to a dark-eyed junco.|