While October provided a non-stop rare bird show on the Cape and Islands, November proved a little quieter, before going out with a bang last week. Two Sundays ago, a biking birder on Nantucket flushed a nondescript gray bird from a dune near Low Beach. This catbird-sized mystery bird with a spotted breast perched up just long enough to reveal that it was, in fact, a Sage Thrasher, representing the first ever record, not just for Nantucket, but for all of the Cape and Islands. Only three other records exist for Massachusetts, all on the North Shore.
Sage Thrashers, as the name implies, are birds of the lovely, desolate sagebrush steppes of the western US, where their beautiful, rambling songs are a big part of the soundtrack. Covering 156 million acres, these desert and semi-desert areas are characterized by little rain, and harsh winters. Sage shrubs dominate, and the few trees are restricted to permanent water sources. Since this ecosystem covers seldom-visited, flyover areas of the west like eastern Idaho and northern Nevada, few people are familiar with Sage Thrashers. In winter, they migrate short distances to similarly shrubby, dry habitats in Arizona and Mexico. Though common and widespread in their preferred habitat, they suffer from the same list of threats as pretty much every species in the American west – overgrazing by cattle, invasive species encroachment, and oil and gas development.
It’s puzzling to me that a short-distance migrant and habitat specialist like the Sage Thrasher would ever end up here. But birds have a way of getting really lost, which is one of the things that gets us birders up in the morning. Maybe family obligations and life’s other plans have made it unlikely that you will be booking that dream birding vacation to the desert shrublands of Utah. But every now and then, if you’re lucky, maybe a bird takes a wrong turn at Albuquerque, and a little bit of the sagebrush steppes will come to you.
Maybe I’m romanticizing things, but that’s what I find really compelling about these rare birds - I think of them as little pieces of distant ecosystems come to visit. A Red Crossbill isn’t just an uncommon finch, it’s a living piece of the vast, cool spruce-fir forests of Canada that broke loose and drifted south. That Painted Redstart that showed up on Cuttyhunk in October is an animated bit of the oak-draped slopes of Mexico’s Sierra Madre deposited here on a southwesterly wind.
The Sage Thrasher appears to be gone, unless someone took it into protective custody until the Christmas Bird Count in a few weeks. But it’s ok – with our track record on the Cape and Islands, another rarity will be along soon. And when it does, remember that with a little imagination, that rare bird can be more than just a bird – if your mind is right, it could evoke an entire, perhaps exotic ecosystem. Think of it as a feathered emissary from a far-away land.