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Another week, another set of rare avian emissaries from the west

Swainson's Hawk
Ashley Tubbs
CC 2.0
Swainson's Hawk

As so often happens, Facebook brought us word of the latest rare bird. A post in the Cape Cod Birders group on Monday showed clear photos of a hawk that, in the parlance of its native lands, ain’t from around these parts. Though vaguely reminiscent of our familiar Red-tailed Hawk, with broad wings made for soaring, the bird in the photo showed dark flight feathers, plain whitish chest and belly, and chocolate brown head and back, betraying its identity as a Swainson’s Hawk, a bird of western grasslands that should be most of the way to southern South America by now. Instead, this bird was circling the dunes of Provincetown.

By the time I saw the report it was two days old because the couple who saw it didn’t believe the Merlin app’s identification of Swainson’s Hawk and were getting the sighting vetted by humans in yet another Facebook group dedicated only to hawk identification. It hasn’t been reported again, but if you’re going to look for a Swainson’s Hawk in Massachusetts, there’s no better place than Provincetown – over the years, at least seven have been reported from the dunes there at the ends of the earth, far more than anywhere else in the state. In fact, none have ever been seen anywhere else on the Cape and Islands save for an old sight report from the 60s in Wellfleet.

Swainson’s Hawks are of the soaring hawk group known as buteos, like Red-tailed Hawks. In spring, out on dry western rangeland and agricultural valleys, they feed their babies typical hawk things, like rabbits and rodents. But the rest of the year, these big hawks mostly eat grasshoppers and other big insects. In fact, they migrate further than any other hawk just to eat grasshoppers in southern Argentina all winter – a bird breeding in northern Canada might travel 17,000 miles round trip per year. Those better be really special grasshoppers. Back in the 90s, that migration did not pay off for many of them – an estimated 20,000 were killed by pesticides used to kill grasshoppers on Argentinian farms.

Swainson’s Hawks bring me back to my time as an official hawk counter – yes that is an actual job – at the River of Raptors hawk count in Veracruz, Mexico over 20 years ago. There, in one of the earth’s great, relatively unheralded wildlife spectacles, close to five million hawks pass through the narrow coastal plain of eastern Mexico each fall en route to wintering grounds in Central and South America. From our official count site on the roof of the Hotel Beinvenido in the small city of Cardel, we might see tens of thousands of Swainson’s Hawks on a peak day in mid-October. As many as 800,000 have passed in a season.

Over on the Vineyard, keeping to the “east meets west” theme of fall rarities, some western songbird counterparts to the Swainson’s Hawk made a visit. A stunning yellow Townsend’s Warbler was photographed in Aquinnah and a more subdued but still exciting Bell’s Vireo in the wilds of Chilmark.

This trio of species, all named for various 19th century naturalists, segue nicely into a topic I’ll need to cover another day. All three species, and many, many others, will all have new names someday – the American Ornithological Society announced this week they will rename all birds named for people, given how problematic some of the people were and the difficulty of sorting out the monsters from the ok guys. Townsend himself is a good example – though he came from an anti-slavery Quaker family and his brother worked with the blind – seems like one of the good ones - it turned out he robbed native American graves to provide skulls to one of the founders of scientific racism. So yeah, time to change the names.

But that’s a topic I’ll fully explore another day. In the meantime, go forth and bird, with the full knowledge that soon you won’t be able to remember the new names of more than 80 species. It will be like when they renumbered the exits on Rt 6, but way worse.

Mark Faherty writes the Weekly Bird Report.