Boulder County last night: owls & nightjars; bats, anurans, & fireflies; nocturnal marsh wrens & grasshopper sparrows; etc.
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Ted Floyd
Jun 6, 2020, 6:27:12 PM6/6/20
to Colorado Birds
Hey, folks.
We saw a bat up there, by the way, during twilight, and I suspect it was a hoary bat, Aeorestes cinereus. A good way to confirm that a whitish bat is that species is to point your recorder (cellphone fine) in the direction of the bat; the hoary bat is anomalously low-pitched, and extremely loud, and even though we humans can't hear the species, our recorders can, and you can totally see the spectrogram if you jack the y-axis up into the 20 kHz band; you should be able to see their freakishly powerful, but inaudible, chirps coming in just under 22 kHz, with their characteristic steep up-sweeps.
On the drive down, we saw a red fox, V. vulpes, trotting right along Flagstaff Road. We also saw massive throngs of disappointed strawberry moon seekers, for it was entirely overcast there, and a bit breezy. And remarkably warm. At the base of the canyon, Andrew heard a yellow-breasted chat, and I heard road noise.
Alright, next it was over to the marshes at the west end of Boulder Reservoir. Practically birdless there, with only a few Canada geese in the distance, but the anuran concert was splendid; three or four species, and the Woodhouse toads, Anaxyrus woodhousii, were just going OFF. The frogs and toads were awesome, but the real show-stoppers were the fireflies, Lampyridae spp., like the Milky Way come down to Earth, in the cattails right along the road. A motorist stopped to inquire what we were doing, and we explained that you have to turn your headlights off to see the fireflies, and the driver said, "Well, that's the dumbest thing, how can you see anything in the dark?" and drove away. Hooooookay. Anyhow, the fireflies just west of Boulder Rez are glorious, they're there for anybody to see, and, yes, I assure you, you need to turn off your lights to see them. Again: Metallica...Berlioz...
I was surprised that the firefly show was so good on the early date of June 5. Usually, in my experience, it's a late-June-into-early-July thing here in Boulder County. I wonder if that means they're just early this year, or, if I might entertain the happy thought, that they're going to be REALLY good in a few weeks.
Next stop: Cottonwood Marsh, where it was still a bit breezy, still overcast, and still warm. We hadn't even gotten out of the car when Andrew announced, "Listen, I can hear a chup-chup-CH'CH'CH'CH'CH'CH'CH'-kizzzzz out there!" Sure enough:
https://www.xeno-canto.org/565791
It's a western marsh wren (Woodhouse toad also audible in that cut), but I shall henceforth refer to it as a chup-chup-CH'CH'CH'CH'CH'CH'CH'-kizzzzz. Hey, it's a lot more descriptive, and arguably more evocative, than X Æ A-12. Anyhow, the bird sang constantly the whole time we were there, and we can tell it's from the western population by the elements of any particular song and, especially, by the variation among the different songs (n=15 in that cut). Don Kroodsma and others think the marsh wren might comprise two species, with both likely occurring in Colorado. So, once you've got the crossbills all figured out (good luck with that), see what you can do with your marsh wrens. There were bats here, too, big brown ones, and I wonder if they were indeed big brown bats, Eptesicus fuscus. I don't know. Also a killdeer flying over. That I do know.
After Cottonwood Marsh, we went to an area of Gun Barrel Hill where I have succeeded in the past in hearing a very special bird while still standing by the car. It required Andrew's supersonic ears, but we got it:
https://www.xeno-canto.org/565789
Final stop: Teller Lake No. 5. The only birds we could hear were ducks, or maybe coots or grebes or fish or a boot, flapping or flopping in the water. But the bats, little brown jobs, were wondrous, frequently flying so close that we could practically reach out and touch them. Not sure what species, but the little brown bat, Myotis lucifugus, seemed reasonable. Saw a raccoon, Procyon lotor, here and heard a troupe of coyotes, Canis latrans.
Andrew Floyd and I, having nothing better to do yesterday evening, Fri.-Sat., June 5-6, decided to go out in search of things that go bump, hoot, huhuhuhuhuhuhu, and p't'tip-pzzzzzzzzz in the night.
We started out up Flagstaff Road, just west of the Boulder city limits, more congested--truly, congested--than I'd ever seen it. But we managed to find a roadside spot far from, or at least not in the immediate vicinity of, the madding crowd. The last of the hermit thrushes were settling down as we ourselves were getting settled in, and the first of the flammulated owls avowed at 8:54pm. The flamms (n=2) never got particularly close, and neither did a common poorwill (n=1) down in a ravine below, but the northern saw-whet owls (n=4) were fantastic. We found ourselves in the midst of a foursome of saw-whets, two of them hooting wildly, a third uttering that eerie and rarely heard whetting-of-the-saw sound, and a fourth giving a shrill whistle that sounds like a cross between a kitten and a wraith. Here's one of them:
https://www.xeno-canto.org/565795
A comment: Owls and nightjars are eminently findable at this time of the year up Flagstaff Road, and you absolutely do not need playback to hear them. They're just singing spontaneously. You don't even have to leave the roadside pull-offs to hear them. And the idea of using lights for enjoying owls is equivalent to blasting your Metallica CD whilst listening to the "Sanctus" from the Berlioz Requiem. Lights are good in certain instances, and so, I suppose, is Metallica, but it is beyond senseless to use lights whilst delighting in the transcendent magic of a chorus of owls.
We started out up Flagstaff Road, just west of the Boulder city limits, more congested--truly, congested--than I'd ever seen it. But we managed to find a roadside spot far from, or at least not in the immediate vicinity of, the madding crowd. The last of the hermit thrushes were settling down as we ourselves were getting settled in, and the first of the flammulated owls avowed at 8:54pm. The flamms (n=2) never got particularly close, and neither did a common poorwill (n=1) down in a ravine below, but the northern saw-whet owls (n=4) were fantastic. We found ourselves in the midst of a foursome of saw-whets, two of them hooting wildly, a third uttering that eerie and rarely heard whetting-of-the-saw sound, and a fourth giving a shrill whistle that sounds like a cross between a kitten and a wraith. Here's one of them:
https://www.xeno-canto.org/565795
A comment: Owls and nightjars are eminently findable at this time of the year up Flagstaff Road, and you absolutely do not need playback to hear them. They're just singing spontaneously. You don't even have to leave the roadside pull-offs to hear them. And the idea of using lights for enjoying owls is equivalent to blasting your Metallica CD whilst listening to the "Sanctus" from the Berlioz Requiem. Lights are good in certain instances, and so, I suppose, is Metallica, but it is beyond senseless to use lights whilst delighting in the transcendent magic of a chorus of owls.
We saw a bat up there, by the way, during twilight, and I suspect it was a hoary bat, Aeorestes cinereus. A good way to confirm that a whitish bat is that species is to point your recorder (cellphone fine) in the direction of the bat; the hoary bat is anomalously low-pitched, and extremely loud, and even though we humans can't hear the species, our recorders can, and you can totally see the spectrogram if you jack the y-axis up into the 20 kHz band; you should be able to see their freakishly powerful, but inaudible, chirps coming in just under 22 kHz, with their characteristic steep up-sweeps.
On the drive down, we saw a red fox, V. vulpes, trotting right along Flagstaff Road. We also saw massive throngs of disappointed strawberry moon seekers, for it was entirely overcast there, and a bit breezy. And remarkably warm. At the base of the canyon, Andrew heard a yellow-breasted chat, and I heard road noise.
Alright, next it was over to the marshes at the west end of Boulder Reservoir. Practically birdless there, with only a few Canada geese in the distance, but the anuran concert was splendid; three or four species, and the Woodhouse toads, Anaxyrus woodhousii, were just going OFF. The frogs and toads were awesome, but the real show-stoppers were the fireflies, Lampyridae spp., like the Milky Way come down to Earth, in the cattails right along the road. A motorist stopped to inquire what we were doing, and we explained that you have to turn your headlights off to see the fireflies, and the driver said, "Well, that's the dumbest thing, how can you see anything in the dark?" and drove away. Hooooookay. Anyhow, the fireflies just west of Boulder Rez are glorious, they're there for anybody to see, and, yes, I assure you, you need to turn off your lights to see them. Again: Metallica...Berlioz...
I was surprised that the firefly show was so good on the early date of June 5. Usually, in my experience, it's a late-June-into-early-July thing here in Boulder County. I wonder if that means they're just early this year, or, if I might entertain the happy thought, that they're going to be REALLY good in a few weeks.
Next stop: Cottonwood Marsh, where it was still a bit breezy, still overcast, and still warm. We hadn't even gotten out of the car when Andrew announced, "Listen, I can hear a chup-chup-CH'CH'CH'CH'CH'CH'CH'-kizzzzz out there!" Sure enough:
https://www.xeno-canto.org/565791
It's a western marsh wren (Woodhouse toad also audible in that cut), but I shall henceforth refer to it as a chup-chup-CH'CH'CH'CH'CH'CH'CH'-kizzzzz. Hey, it's a lot more descriptive, and arguably more evocative, than X Æ A-12. Anyhow, the bird sang constantly the whole time we were there, and we can tell it's from the western population by the elements of any particular song and, especially, by the variation among the different songs (n=15 in that cut). Don Kroodsma and others think the marsh wren might comprise two species, with both likely occurring in Colorado. So, once you've got the crossbills all figured out (good luck with that), see what you can do with your marsh wrens. There were bats here, too, big brown ones, and I wonder if they were indeed big brown bats, Eptesicus fuscus. I don't know. Also a killdeer flying over. That I do know.
After Cottonwood Marsh, we went to an area of Gun Barrel Hill where I have succeeded in the past in hearing a very special bird while still standing by the car. It required Andrew's supersonic ears, but we got it:
https://www.xeno-canto.org/565789
That is a grasshopper sparrow (p't'tip-pzzzzzzzzz), in my mind one of the most enchanting of all night-singing bird species. Andrew's ears were indisputably useful, but I think we got an assist from the full moon, too. It finally came out, if only for a few minutes, and I suspect the moonlight induced the sparrows, plural, to amp up their singing. No pix of the birds--in fact we didn't see any birds at all last night--but here's my human companion, watching the moon and listening to sparrows:
You might have noticed some crickets in that cut of the grasshopper sparrow. How could you not have noticed them? But if you somehow overlooked the crickets, here they are in all their glory:
https://www.inaturalist.org/observations/48673024
They're field crickets in the genus Gryllus, and pretty likely G. veletis, I think. We heard a couple of insomniac western meadowlarks at this stop, too.
After the sparrows and crickets and meadowlarks, we popped in on Sawhill--yeah, for those of you who know the Boulder County lowlands, our itinerary had, by this point, become altogether haphazard. It was overcast again, fully and thoroughly and completely overcast, and a winnowing Wilson snipe was going berserk. The snipe's winnowing (huhuhuhuhuhuhu) is a sonation, not a vocalization, made with the bird's tail. Who knew! I don't think the snipe ever got particularly close to the ground, and that was sort of the point--that disembodied sound, spooky and supremely soothing, waaaaay up there, utterly indifferent to Andrew and me and the fishermen and frogs below. (Frogs: North American bullfrogs, Lithobates catesbeianus, and chorus frogs, Pseudacris spp.)
https://www.inaturalist.org/observations/48673024
They're field crickets in the genus Gryllus, and pretty likely G. veletis, I think. We heard a couple of insomniac western meadowlarks at this stop, too.
After the sparrows and crickets and meadowlarks, we popped in on Sawhill--yeah, for those of you who know the Boulder County lowlands, our itinerary had, by this point, become altogether haphazard. It was overcast again, fully and thoroughly and completely overcast, and a winnowing Wilson snipe was going berserk. The snipe's winnowing (huhuhuhuhuhuhu) is a sonation, not a vocalization, made with the bird's tail. Who knew! I don't think the snipe ever got particularly close to the ground, and that was sort of the point--that disembodied sound, spooky and supremely soothing, waaaaay up there, utterly indifferent to Andrew and me and the fishermen and frogs below. (Frogs: North American bullfrogs, Lithobates catesbeianus, and chorus frogs, Pseudacris spp.)
Final stop: Teller Lake No. 5. The only birds we could hear were ducks, or maybe coots or grebes or fish or a boot, flapping or flopping in the water. But the bats, little brown jobs, were wondrous, frequently flying so close that we could practically reach out and touch them. Not sure what species, but the little brown bat, Myotis lucifugus, seemed reasonable. Saw a raccoon, Procyon lotor, here and heard a troupe of coyotes, Canis latrans.
Well, starting with the first flam just before 9pm and wrapping up with the snipe just before 2am, we found a grand total of ten (10) bird species the whole time we were out there, and, as I said earlier, we never actually laid eyes on any birds. But it was an unforgettable night of birding and nature study, and we celebrated on the way back home to Lafayette with a bag of baked cheddar jalapeño pretzel Combos®:
Ted Floyd
Lafayette, Boulder County
Sandra Laursen
Jun 9, 2020, 9:23:13 PM6/9/20
to Colorado Birds
Just a note that you, Ted, reported fireflies on June 9-10, 2017, according to the search function on this august list. So they are early but have been early before!
- Sandra Laursen
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