All last week, I was honored to be at the ABA’s 2014 convention in Corpus Christi, Texas. My favorite bird down there, I have to say, was the Long-billed Thrasher. Long-billed Thrashers were everywhere!–in city parks in downtown Corpus, in upland thickets far from the coast, and in suburban yards right along the saltwater bays and lagoons. I didn’t see a lot of these thrashers, but I sure heard them. The songs of Long-billed Thrashers are unmistakable: wild and twangy, exuberant, they just go on and on and on.
There’s just one problem.
Here in the ABA Area, Long-billed Thrashers and Curve-billed Thrashers come into some amount of contact in South Texas. True, the two species tend to sort out by habitat–Long-bills in woodlands, Curve-bills in the desert. But that wasn’t the case on an ABA Convention field trip Jeff Bouton and I co-led this past Saturday. We were birding a super-productive stretch of eastern Kleberg County, and an astute trip participant asked a perfectly reasonable question: How do you distinguish the songs of Long-billed and Curve-billed thrashers?
Tom Stephenson, in his article in the March/April 2014 Birding (pp. 38-42), states that it is “impossible” to learn the songs of thrashers. That sounds depressing. But Stephenson’s message is actually a hopeful one. Yes, it’s hard enough to learn the song of any particular thrasher, and, practically speaking, impossible to learn all the songs of an entire population of thrashers. But it’s easy to learn a few basic rules–thrasher “grammar,” if you will. For example, this species has clicking notes, but this one doesn’t; this species has even phrasing, but that species has clear breaks or pauses; this species’ song goes way up and down in pitch, but that species’ song spans a relatively narrow range of pitch; and so forth. Learn just a few of these rules, and the “impossible” thrashers suddenly become gratifyingly easy.
Stephenson’s article focuses on the five “desert thrashers” of Arizona–Le Conte’s, Crissal, Bendire’s, Curve-billed, and Sage. The article spells out, in words, the essential grammar of each species’ song. The article also depicts, in pictures called sound spectrograms, what the thrashers’ songs look like. It’s great birderly discipline to learn bird songs in words and pictures, but, let’s be honest, even the most sophisticated of us benefit immeasurably from hearing birds sing. And it’s hard–er, impossible, literally so–to hear birds on the printed page. So, without further ado, we herewith present the songs of the five thrashers described and depicted in Tom Stephenson’s article:
Alrighty, we have the desert thrashers all figured out. But what about Curve-billed vs. Long-billed? Here’s a link to a recording I made of a Long-billed Thrasher from that ABA Convention field trip a few days ago:
Any thoughts on how to distinguish Long-billed from Curve-billed?