Date: 6/14/26 3:29 pm From: Ted Floyd <tedfloyd73...> Subject: [cobirds] SparrowFest at The Arsenal + more on recording in the wind
Hey, all.
With Pete Christiansen, Jason Zolle, Jeff Percell, and Michael Ward, I
enjoyed a nice day yesterday, Sat., June 13, of eBirding and iNatting at
Rocky Mountain Arsenal National Wildlife Refuge, Adams Co. The weather was
pleasant: temps a bit below the seasonal average, with some clouds rolling
in by mid-day, and winds kicking up after sunrise. More on the wind in a
bit.
The highlight was an excellent showing by several passerellid species. We
detected 37 *Cassin sparrows,* 80 *grasshopper sparrows,* and 87 *lark
buntings.* And those were, of course, just trailside and roadside
detections; Lord knows how many are out there altogether. An eclecticism of
other avian highlights included: a male *black-chinned hummingbird,*
seemingly on territory; a *Virginia rail,* singing the male-song in the
middle of the day; a *western cattle-egret* strutting along the shore of
Lower Derby Rez; two *Mississippi kites* swooping and sailing over
Lower/Little Havana; just one *burrowing owl* (I think they're mostly down
in the their holes right now, tending young and out of sight); a c*ordilleran
flycatcher* giving the "position note" in Upper Derby woods; one
audio-supported presumptive *eastern warbling-vireo* and four unsupported,
and unsupportable, warbling-vireos (more on this below); a *sage thrasher,*
in ideal breeding habitat (sandsage + saltbush) at Big Blue Stem; and three
*dickcissels*, one at Big Blue Stem, two singing along the wildlife drive.
In the one-that-got-away category: a brief apparition from a scolopacid
that likely was a white-rumped sandpiper. And as to non-avians, at least
four prairie racerunners, *Aspidoscelis* *sexlineatus viridis*, in a New
Mexico locust grove.
The Cassin sparrow show at The Arsenal is impressive. Check out this eBird
output, indicating some combination of: (a) legitimate species biology; and
(b) the pernicious positive feedback loop of observers going to places
where birds have previously been reported. As Andrew Floyd casually
inquired, on seeing this result: "Did *you* contribute to this bias?" Lol,
guilty as charged: We ticked the species at 10 "daughter" hotspots at the
"mother" hotspot for The Arsenal. Anyhow:
[image: CaSp output.png]
Okay, recording birds in the wind. Nathan Pieplow recently recommended
recording from our wind-baffled trousers pockets. I remember an incident,
eons ago, on a windy winter morning in Boulder when Bob Zilly yanked off
one of my mittens, wrapped it around my recorder, and *voilà *, the peak
meter, indicating wind noise, dropped to near-zero. That's cool. But if you
want the ultimate wind baffle, try a *CAR. *🚘 Here's one of yesterday's
Cassin sparrows, out on the windswept wildlife drive at The Arsenal:
[image: C01 CaSp.png]
You can tell from the almost perfectly straight flatline on the waveform
function (bottom panel). Srsly, if recording from within a pocket or mitten
does the trick, doing it in a car, as above, takes things to a whole new
level of acoustic purity.
Here's a grasshopper sparrow, atop windy Rattlesnake Hill yesterday at The
Arsenal:
[image: C02 GrSp.png]
Something poignant for peeps, like me, with deleterious alleles for the
LOXHD1 and TRIOBP genes (tl; dr— you got age-related high-frequency hearing
loss), is the strong signal at the 0.77-sec. mark. First, a plea for
birders to examine not just the popular sound spectrogram output (top
panel), but also the richly informative waveform function, or oscillogram,
output (bottom panel). Look at all those millipascals reaching the
defective cochleae of my inner ear at around 0.77 sec.; given that the
powerful signal has a carrier frequency just under 6 kHz, I can still
totally hear that sound, and I've disciplined myself in recent summers to
be consciously attuned to it. Which means I typically get on a singing
grasshopper sparrow 300–500 ms before the kids do. Even if it's the *only*
part of the song I can hear on a grasshopper sparrow singing at any
distance. 😬
Next up. There are *Brewer* *sparrows* out there! Not nearly as many, this
summer, as there are Cassin and grasshopper sparrows. To find a Brewer
sparrow at The Arsenal, try the sandsage–saltbush admixtures, as, for
example, at Big Blue Stem. Here's one singing in the wind:
[image: C03 BrSp.png]
Although the recording is acoustically noisy, with "white noise" (actually,
*gray* noise in all such outputs) throughout, it's not all that bad, for
the perhaps counterintuitive reason that the bird was singing out in the
open. Open environments are, on the whole, acoustically simple, having the
useful effect of driving wind noise down into the lowest registers. That's
suboptimal if you're trying to hear (and record) owls, pigeons, and
subwoofers, but not so bad for sparrows, katydids, and dog whistles.
More challenging, and where the Pieplow–Zilly Theorem really comes into
play, is in acoustically complex environments like the decently dense grove
at Upper Derby. Here's a presumptive eastern warbling-vireo yesterday at
Upper Derby:
[image: C04 EaWV.png]
Lots of "white" (gray) noise in that one, even though, subjectively, it
didn't seem bad, as we were "out of the wind." So we were, in terms of
broadband activation of our epidermal mechanoreceptors. But the wind's
sound energy (those pesky millipascals) don't magically go away.
Hello?—First Law of Thermodynamics? The wind is still there, but it's
distributed everywhere in the environment, manifested as this sort of dull
reverb that we don't consciously pick up on but that nevertheless
diminishes our sensitivity to discrete sounds in the environment. (*Cf*.
the well-known problem of struggling to discern sibilant phonemes at
cocktail parties.)
Two other things:
1. Nathan issues a plea for longer(ish) cuts of birdsong, and that's
especially advisable, I would say, in the case of variable vireos. Ed
Pandolfino has a paper in *Western Birds*, a while ago, on the songs of
Cassin and plumbeous vireos, and he makes the point that it's actually
*impossible* to identify—or, at least, credibly attempt to identify,
haha—those two species from audio cuts less than about a minute in
duration. Sorry, this cut from The Arsenal is only 15 seconds, presented
here as COBirds-suitable imagery, rather than Pandolfino-compliant output.
Father Ed: Forgive me.
2. You've all been waiting for the other shoe to drop. 👠Yeah, we all need
to provide such support for our species-level warbling-vireo IDs in
Colorado. Pete, Jason, Jeff, Michael, and I actually heard five (*n*=5)
candidate eastern warbling-vireos yesterday at The Arsenal, but we got
spectrogram-supported audio on just this one. Therefore, we eBirded one
eastern and four "spuhs" (eBird taxon "Eastern/Western Warbling Vireo") for
our visit yesterday at The Arsenal. There's no shame in that! Indeed, it
signals that you are a competent, science-based birder. Just do it. Or, I
suppose, don't do it.
Ted Floyd
Lafayette, Boulder Co.
P. s. Two more things on warbling-vireos. I cannot help myself.
First, for peeps keeping tabs on the presumptive easterns at Walden Ponds,
Boulder Co., catastrophe struck back on Wed., June 10! Check out this audio
and, especially, the comments appertaining thereunto:
macaulaylibrary.org/asset/659462219
Second, while we're all excitedly adding presumptive eastern
warbling-vireos to our county lists, let's not overlook the coolness of
presumptive western warbling-vireos. They can get amped up ("a vireo on
speed") like easterns, they are super-variable, and they'll sometimes sneak
in a terminal "squirt!" note in the song. For the ultimate surround-sound
experience with presumptive western warbling-vireos, ride the gondola at
Telluride, San Miguel Co. For the poor man's experience, try Gregory Canyon
in Boulder Co., full of songsters like this one, singing up a storm back on
Mon., June 8:
macaulaylibrary.org/asset/659334751
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