Hello, Birders. Earlier "today," Tuesday, August 31st, in the 2am hour, winds aloft were southwesterly (not good), but there was nonetheless a modest flight of nocturnal landbird migrants (30+ flight calls per hour) over Greenlee Preserve, Lafayette, Boulder County. It was mainly expected stuff: Wilson's Warblers and Chipping Sparrows, plus a few others.
I also heard a single Upland Sandpiper, at 2:06 a.m. Which brings me to a recent remark by everybody's favorite Colorado birder-in-exile, Tony Leukering: > I've recently read most of the posts about the McIntosh loon and > nocturnal flights of migrants and had a few things to write in response. > First off, the pattern that I see in Ted's Upland Sandpipers-over-Boulder > data, is that insomniacs detect more nocturnally-migrating Uppies than > do most other birders. I mean, I'm almost always up around 11:30 pm, > but only rarely so after 2 am. Thus, I hear very few Uppies going over, > Boulder or elsewhere. First, I'm not an insomniac. It's just that I don't like sleeping... ;) Regarding nocturnal migration, it's important to consider that Upland Sandpipers are *not* strictly nocturnal migrants. They migrate day and night...to which you might say, "Gee, when do they ever rest?" And that's where it gets fascinating. In recent conversations with Bob Gill, an expert on long-distance migration by shorebirds, I've learned that a key assumption of mine about Boulder County's Upland Sandpipers may well be wrong. After hearing Upland Sandpipers on nocturnal migration over Boulder County in July and August of 2009, I assumed that these birds were coming in from nearby--northeastern Colorado, the Nebraska Panhandle, etc. But Bob says that's probably not the case. Instead, he thinks we're listening to no-nonsense, high-altitude, super-strong flyers on practically non-stop flights from as far away as cental Alaska. We're hearing the overland equivalent of those amazing trans-Pacific shorebird migrants like Bar-tailed Godwit and Bristle-thighed Curlew. "Our" Upland Sandpipers may well fly all night, and then they just keep going--throughout the next day, and perhaps into the next night, and so forth... So why don't we hear them by day? Well, that's the cool part. They're up there, but we don't notice, or we misidentify them. By day, there are lots of other distractions--for starters, all the things we can SEE in broad daylight. That distracts us. Or: We do hear Upland Sandpipers by day, but we misidentify them. It was gratifying, in a way, to learn just a few days ago that one of Colorado's greatest birders had until recently ALSO been been confusing the Upland Sandpiper's flight call with the distinctive call of the Curve-billed Sandpiper. Me too! (Until I "discovered" the difference, just last year.) Seriously, the "quiddyquit!" call of the sandpiper can sound surprisingly similar to the "whit-whit-wheet!" of the thrasher. By day, in south-central Colorado's canyonlands, you might well just write off that diurnal migrant Upland Sandpiper as a "distant Curve-billed Thrasher." This developing Upland Sandpiper saga is a classic example, it seems to me, of the human tendency to stick to what we know. We all "know" that the skies of Colorado aren't filled with the flight calls of high-altitude migrant Upland Sandpipers en route from Alaska to Bolivia; and since we "know" that, we concoct alternative realities. Either we don't hear the flight calls at all, or we write them off as Curve-billed Thrashers or Lesser Yellowlegs (that's another alternative hypothesis I've encountered) or something. I love it. To me, the absolute greatest joy of birding--in life, really--is getting thrown for a loop. Seven years ago, I had no idea you could go out at night in late July in the Front Range and hear large numbers of Chipping Sparrows on nocturnal migration; five years ago, I still had no idea what those Chipping Sparrows actually were doing, namely, migrating by night to their faraway molting grounds. Just two years ago, I had no idea you could reliably expect to hear Upland Sandpipers flying over Boulder County; and just one year ago, I had no idea those sandpipers were probably on long-distance flights from places far to our north and west. Continuing in this vein, I got thrown for a loop just yesterday morning, Monday, August 30th, while listening to a very heavy dawn flight over Lafayette. Rather than ramble on about it, I'll just direct you to comments I've already posted to the NFC-L (nocturnal flight calls) list: http://www.birdingonthe.net/mailinglists/NFCL.html#1283211864 Oh, and I have a final thought. If you've been outdoors at all for the past week or so, you've surely noticed that we've been languishing under icky south winds seemingly forever. Well, that's supposed to change over the next few days, with a variable but generally northerly flow. (Or vector. Nick Komar: flow=vector, heh!) Anyhow, I cautiously predict that there may be a good night flight at some point by week's end. ------------------------------- Ted Floyd Editor, Birding Follow Birding magazine on Twitter: http://twitter.com/BirdingMagazine ------------------------------- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
