Currently a Hudsonian Godwit is along the northeast shore of Crom Lake (Weld CR 31 between 88 &90).
Dave Leatherman
Fort Collins
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Monday, 15 June 2026
[cobirds] Osprey Update and a question
The Osprey pair are settling in and continually adding to their nest. It is mid-June now, and guess who is starting to sit on eggs? They have been actively breeding for the past few days. I see the female sitting in the nest more often now instead of perching on the edge of the box. The male is now always close by. If he isn't on the perch or the edge of the box, he is in the trees nearby.
Isn't this awfully late for them trying to raise a family? Up to now, I've just been assuming that they are newly bonded and playing house. Looks like it is getting more serious. They are also more vocal, constantly calling to each other.
What should I make of all of this?
Pauli Smith
Highlandlake/Mead, Weld county, CO
[cobirds] Cassin's Kingbirds - Rio Blanco Co.
They’re Baaack! Yesterday morning (Sun, 14 Jun’26) while running our Breeding Bird Survey (BBS) east of Rangely (Rio Blanco Co., CO) we found at least two (2) CASSIN’S KINGBIRDs in the same spot where we first found them way back in 2021! What I find very interesting about this extralimital repeat is that we hadn’t had them there the past two (2) years, only to find them in the same spot as they nested in 2023 (unfortunately they won’t show up in the official BBS results as we found them outside the allotted time on our way back out). We figured they had given up their Mission after failing to attract more settlers, but the optimism of pioneers apparently carried on. If these are indeed the same individual birds, they would be at least six (6) years old as we found them as adults during our first year covering this route (Angora BBS) back in June 2021. While certainly plausible, it is also possible at least one is an offspring given the site fidelity – the armchair ornithologist in me wishes would have had them banded to know for sure. In any case, this is a fascinating occurrence for a rare species in northwestern Colorado. If you’d like specific details on the location, please let me know separately.
Good BBSing,
Doug
Sunday, 14 June 2026
[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 cordilleran 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.
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 cordilleran 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:
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:
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:
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:
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:
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.)
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:
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.
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:
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:
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Saturday, 13 June 2026
Re: [cobirds] How to record audio in windy conditions
I use a good shotgun microphone and a digital recorder. However, years ago i birded with randy Little in new jersey. Randy did all the original sound recordings for the Peterson field guides using a large parabolic dish microphone
On Sat, Jun 13, 2026, 4:54 PM Mary Keithler <mkeithler@gmail.com> wrote:
Hi Nathan,--
Thanks for the timely recording tips and the heads up on the Merlin updates we can look forward to. Sounds very handy.
Mary
Sent from my iPhone
On Jun 13, 2026, at 4:11 PM, Nathan Pieplow <npieplow@gmail.com> wrote:
--Hi everybody,
In recent days I've seen several examples of a classic Colorado birding problem: people try to record audio of a bird, but there's simply too much wind, and the recording ends up being unusable, or nearly so.
If you find yourself in this situation, I recommend that you start up Merlin and then put your phone in your pocket. The fabric then acts as a makeshift windscreen. It usually doesn't dramatically affect the levels from the bird sound, but it can greatly cut down on wind noise.
In a few weeks, we will all have the ability to send recordings from Merlin directly to eBird on our phones. This will also come with the ability to trim recordings in Merlin. If you do the phone-in-the-pocket trick, it will be important to trim away the not-in-pocket parts of the recording to ensure the best levels on the resulting online audio.
While I'm at it, I'll exhort everyone to please keep your recorder running longer than you might be tempted to. I've been asked to identify a bunch of ten-second and twenty-second recordings of Warbling Vireos recently, and it's not always possible. The longer your recordings, the better, especially for things like Warbling Vireos or any kind of rarity. Longer recordings are easier to ID and can be used in a wider variety of scientific research.
Thanks, and good birding!
Nathan PieplowBoulder
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Re: [cobirds] How to record audio in windy conditions
Hi Nathan,
Thanks for the timely recording tips and the heads up on the Merlin updates we can look forward to. Sounds very handy.
Mary
Sent from my iPhone
On Jun 13, 2026, at 4:11 PM, Nathan Pieplow <npieplow@gmail.com> wrote:
--Hi everybody,
In recent days I've seen several examples of a classic Colorado birding problem: people try to record audio of a bird, but there's simply too much wind, and the recording ends up being unusable, or nearly so.
If you find yourself in this situation, I recommend that you start up Merlin and then put your phone in your pocket. The fabric then acts as a makeshift windscreen. It usually doesn't dramatically affect the levels from the bird sound, but it can greatly cut down on wind noise.
In a few weeks, we will all have the ability to send recordings from Merlin directly to eBird on our phones. This will also come with the ability to trim recordings in Merlin. If you do the phone-in-the-pocket trick, it will be important to trim away the not-in-pocket parts of the recording to ensure the best levels on the resulting online audio.
While I'm at it, I'll exhort everyone to please keep your recorder running longer than you might be tempted to. I've been asked to identify a bunch of ten-second and twenty-second recordings of Warbling Vireos recently, and it's not always possible. The longer your recordings, the better, especially for things like Warbling Vireos or any kind of rarity. Longer recordings are easier to ID and can be used in a wider variety of scientific research.
Thanks, and good birding!
Nathan PieplowBoulder
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[cobirds] How to record audio in windy conditions
Hi everybody,
In recent days I've seen several examples of a classic Colorado birding problem: people try to record audio of a bird, but there's simply too much wind, and the recording ends up being unusable, or nearly so.
If you find yourself in this situation, I recommend that you start up Merlin and then put your phone in your pocket. The fabric then acts as a makeshift windscreen. It usually doesn't dramatically affect the levels from the bird sound, but it can greatly cut down on wind noise.
In a few weeks, we will all have the ability to send recordings from Merlin directly to eBird on our phones. This will also come with the ability to trim recordings in Merlin. If you do the phone-in-the-pocket trick, it will be important to trim away the not-in-pocket parts of the recording to ensure the best levels on the resulting online audio.
While I'm at it, I'll exhort everyone to please keep your recorder running longer than you might be tempted to. I've been asked to identify a bunch of ten-second and twenty-second recordings of Warbling Vireos recently, and it's not always possible. The longer your recordings, the better, especially for things like Warbling Vireos or any kind of rarity. Longer recordings are easier to ID and can be used in a wider variety of scientific research.
Thanks, and good birding!
Nathan Pieplow
Boulder
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