Please find here my report for Plumbeous Vireos from Steens Mountain, Harney County, on June 5th of this year.
Adrian
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On June 5th, 2020, Chris Hinkle, our mom Em Scattaregia, and I observed a pair of Plumbeous Vireos on Steens Mountain. They were 1.5 miles east of the South Steens Campground, along the Indian Creek Trail. We first heard one singing persistently for a couple minutes, and finally spotted it moving through a thick juniper tree. We tracked it for about a minute, then saw it fly down the slope and heard it singing more distantly. This was about 11:15am. We returned an hour later and again heard it singing, and tracked it down for a second view. While we were observing it, a second individual briefly sang in response (for about thirty seconds). The second song was very similar to the first: it was slow with longer pauses and shorter notes than Cassin's Vireo. We never saw the second bird, but heard it singing while we could see and hear the original bird.
Appearance: Slate gray vireo, not super washed out as Cassin's often are this time of year. It had two crisp, bold white wingbars. The throat was white, contrasting sharply with the dark gray hood. It had standard "solitary vireo" white spectacles. The flanks had a bit of medium gray coloration on them, and no hint of yellow or green. Overall it was a fairly small, shortish-tailed vireo with a medium to smallish bill. The dark gray upperparts and clean white wingbars, throat, and belly made for a two-toned appearance, rather than the drab appearance of a dull Cassin's.
Behavior: Moving through mid to upper levels of juniper in methodical, typical vireo-like manner. Sang for up to a minute in a given tree, then would move a few trees over and continue singing. Occasionally paused song for a minute or two at a time. Seemed to be repeating a loop through a small section of trees (maybe an acre's worth of area) that was part of a continuous juniper woodland.
Habitat: juniper woodland on gentle to moderately steep slope. Moderately dense forest, with very large junipers (some with big branches stooping down to the ground). Appears to be relatively mature forest. Little groundcover.
Documentation: recordings and two photos are included. Because I was focusing on obtaining these, I couldn't get a more thorough description of what I saw. Chris focused on getting good looks (mine were also good, just brief - maybe 10 seconds through bins) and will hopefully send in a separate report. For the photos, note the grayish flanks, contrasting throat, and bold wingbars. The lack of green or yellow tones isn't conclusive for Plumbeous, but combined with the other features it seals the deal. It was a sunny day and the juniper tree didn't seem to be casting any weird shadows or reflecting light in any deceptive ways.
PLVI-2020-19 (Plumbeous Vireo) 1st Round vote September 16, 2020
ACCEPTED: 7 NOT ACCEPTED: 2
ACCEPTED, verified Good details. I was surprised by the description as "fairly small, shortish-tailed vireo." To me, the Cassin's, Plumbeous, and Blue-headed are the biggest-looking North American vireos. Some of the small-headed, long-tailed species (Red-eyed, Black-whiskered, etc.) may measure longer, but they look slender and slight, rather than chunky.
I'm satisfied that this is a PLVI. I could not detect greenish edges on secondaries nor any yellow wash on flanks to suggest that this might be a CAVI.
I m c mf able acce ing hi a a Pl mbe Vi e E en h gh he h a e emi-decent, you can still make out the uniform gray upperparts, mostly whitish underparts, and remiges that appeared lined with white (instead of yellowish). This greater area has produced at least one breeding pair each of the past 3-4 years, but usually lower in elevation near Page Springs Campground. As for the song, I can hear what Adrian is talking about, but struggle in confidently separating these two species (CAVI and PLVI) by vocal structure alone.
Excellent description and documentation: crisp white wing bars, sharp gray to white margin at the throat, and lack of yellow/green tones are diagnostic
No comments
No comments
Looks good for PLVI. I have the (perhaps mistaken) impression that, unlike CAVIs, Plumbeous Vireos appear to have gray vests, as this one does.
No comments
The overall gray coloration of the back and head together with the white breast and flanks eliminates Cassin's Vireo and Blue-headed Vireo. The edges of the secondaries are difficult to see in the photos, but appear to be gray. The recording of the bird's song is consistent with that of a Plumbeous Vireo.
NOT ACCEPTED: This is not a "no" vote, but I want to put this record into a holding pattern for now. The documentation is strong, but this is one of the most notorious and frustrating ID challenges we face from time to time, so I want to be careful and take our time with every Plumbeous submission. ... First, a disclosure: I did not chase this bird, but instead hiked a different trail a couple of miles away from this bird just a couple of days later, and found my own singing Solitary-type vireo -- and the experience was humbling. I spent about 2 hours following the bird, getting plenty of views and obtaining extensive video and audio evidence. In the field with my eyes the bird struck me as a sharp and clean-cut gray-and-white vireo with only the faintest occasional hint of yellowish on the flanks, and essentially my eyes convinced me I had a Plumbeous -- and had I written up a sight-only record, I would have written up something that I and other would have found highly persuasive. But at home in the screenshots from my video, some images appeared as my eyes and brain had seen the bird, while others showed areas of soft yellow-green that had never entered my consciousness. There were likely reflective effects of the juniper greenery on the bird's pale underparts, and this is hard to tease apart from real plumage color -- and I also wondered whether a camera lens might be liable to pick up or create yellow tones that are not evident in life. Honestly, I could pluck out 2 or 3 shots and convince myself and anyone else it was a Plumbeous, and then pluck out 2 or 3 others and have the decision change to Cassin's. I then sent several of my audio recordings to Ed Pandolfino, who has been analyzing Cassin's and Plumbeous songs in the northern Great Basin for some years and is just about to come out with a paper in Western Birds on the topic. He told me the sonograms showed my bird to have about a 90% chance of being a Cassin's, based on the single best sonographic indicator he and his co-author had come up with. The whole experience left me a bit shaken, though not at all surprised, because most of us, both personally and as part of this Committee, have "been there before" with this species. Anyway, with all that background out of the way..... The written description for the Hinkles' bird(s) is convincing and persuasive, but frankly I'm not sure that means a whole lot to me anymore with these particular vireos, even when it comes from the best and most trusted observers. The two photos are very welcome but cannot sway me in either direction. So I'm left with the audio recording. It is faint, and only some of the phrases show up clearly enough in the sonogram to allow the kinds of measurements that Ed has done with his many recordings and that he did with mine. I tried my best to mimic Ed's technique, measuring the midpoint frequency of each phrase, and came up with an average of either 3094 Hz or 3125 Hz -- either of which would put the bird squarely into the Plumbeous category. Hurray! So, *IF* I did the measurements right, and *IF* the recording quality was in fact good enough to be trying to make these measurements in the first place, then I think I would be willing on this basis to accept this record as a Plumbeous Vireo. But I would like to wait for Ed's publication to come out (it's slated for the next issue), and I would like for us to send the recording to Ed for his personal analysis. I'm expecting he will probably say it's consistent with Plumbeous, and at that point I will gladly accept the record. But I'm most comfortable in a holding pattern until then.
I will likely end up accepting this record, but want to push it to the second round to see the opinions of others. The song certainly sounds consistent with this species with the steady cheree cheroo, but I'm not sure I can confidently and consistently distinguish the songs of these two vireos and that a simple Cassin's song couldn't sound the same. The photo is not diagnostic to my eye. It's too blurry and I think I'm seeing a hint of yellow to the underparts although that could be an artifact of the quality of the photo or reflection from the green undergrowth. The photo also does not clearly show the coloration of the upperparts and again appears to show a hint of green to my eye, but again this could be an artifact of photo quality and surroundings. The observer did not note the coloration on the edging of the secondaries, which is the key feature to separate Plumbeous from a drab, worn Cassin's, although the observer did say the bird completely lacked yellow tones. I'm hesitant to attribute the overall lack of yellow tones to include the secondary edges without a specific description though. Overall, I think it's quite likely these were two Plumbeous Vireos, particularly considering the expertise of the observers and the habitat and behavior described. However, I think this skirts the bar of sufficient information to document a Plumbeous, so I'm going to hold off for at least this round.
The description sounds good for PLVI, and the photos overall seem to support that ID. However, it looks to me that there is a greenish tint to the secondary edges in one of the photos. Unfortunately, the picture is slightly blurry, and I can't say for certain whether the greenish color is just an artifact of the photo or the true color of the secondary edges. Unfortunately, the description does not address the color of the secondary edges - one of the more important field marks in separating CAVI and PLVI. To my ears, the sound recording is not entirely conclusive - I've heard many variations of CAVI, some of which can approach the typical song of PLVI. I'm curious what others think and would like to discuss my reservations, hence I vote to not accept in the first round.
PLVI-2020-19 (Plumbeous Vireo) 2nd round voting December 6, 2020
Accepted: 5 Not Accepted: 4
ACCEPTED, VERIFIED No comments
In addition to my first round comments, IMO the phrasing in the voice recording is to slow to be a Cassin's Vireo.
No comments photo and song support id
I understand and respect other s reser ations concerning this report Its a er challenging species comple with myriad pitfalls. That being said, I still feel confident enough that dull CAVIs have been eliminated. Even though the photos are semi-decent and perhaps equivocal in some aspects , the observers are top notch birders, and it sounds like they got better, more discerning views in addition to was provided in the photos. If Jay provides us with an analysis of the recording at some point, which points in favor of CAVI over PLVI, we can revisit this record .
While the photos of this bird aren't quite as clear as would be optimal, I continue to believe that they are adequate to eliminate Cassin's Vireo. I don't think I have ever seen a Cassin's Vireo that looks as gray as the bird in the photo. The written description also strongly supports the identification of this bird as being a Plumbeous Vireo.
Excellent description; sounds right on
NOT ACCEPTED I concur with [another committee member] that this record should be placed on hold until we can get an analysis of the sonogram. Consider this to be neither a No vote or a Yes vote.
I would like to push this to the third round given my earlier reservations and Jay's comments. I think it's a great idea to have the sonogram examined by the expert in the field of distinguishing the similar songs of the two species. I think it's more likely this is a Plumbeous than a Cassin's, but the additional analysis would make me more comfortable in accepting this record as such.
Well, the Pandolfino-Ray paper finally came out just a few days before our deadline, and it can be found here: https://archive.westernfieldornithologists.org/archive/V51/51(4)-p293-p306.pdf. I have re-done my measurements of the audio clip follo ing the paper s methodologies and have ended up with a mean midpoint frequency of 3089 Hz, or possibly 3106. Going by Table 4 of the paper, this would give us a 4% or likelihood that such a bird as a Cassin s erroneousl classified as a Plumbeous Thus this data gi es us a 95-96% probability that the bird is a Plumbeous, based on song alone. That seems pretty darn good, but whether it is good enough is a subjective question (what level of certainty do we aim to require in accepting a record?). And of course, this calculation is based on only the 8 song phrases in the recording that are clear enough, judged against a sample of 64 vireos from throughout their ranges, which it could be argued is a pretty small sample in the grand scheme of things. Perhaps most relevant is the fact that it s possible m measurement methods ma ha e differed some hat from those of the paper s authors despite m best efforts Therefore I sent m results and the Hinkles s audio clip to Ed Pandolfino ith a request for his analysis, and I will forward that to us all hen I hear back from him Until that time I think I ll continue to ote no just to hold this record in the queue As stated earlier I don t think the photos sho enough to judge the bird s identit Aside from midpoint frequenc there is apparently no way to safely identify these birds b sound The obser ers ritten description is good but lea es out addressing the secondar and tertial edgings. And then, dare we get into it, there is the issue of hybridization. Honestly, I think the status of Plumbeous Vireo in Oregon ill probabl be a mess for the remainder of our lifetimes I m not sure hich a I ll ote on this particular record if it goes to rd round but I think at some point e ma ant to go through all Oregon reports systematically and decide what standards we want to apply.
I've changed my answer because I like Jay's idea: send the audio to an expert and/or wait until the paper is published and we can be certain the spectrogram is being evaluated correctly.
Although this is most likely a PLVI, I am still bothered by the apparent greenish tones in the photos, which suggest the possibility of greenish secondary edges. Despite the observers' experience, I feel that this report does not fully meet the rather strict standards I would like to see in any reports of this very hard -to-identify species in OR. Photos tooo blurry, sound recording not 100% conclusive, and description lacking some key factors (e.g., secondary edges). I'd rather err on the side of caution on this one.
PLVI-2020-19 (Plumbeous Vireo)
3rd round vote Annual Meeting July 17, 2021
Accepted: 8 Not Accepted: 0
Adrian could not vote, as he submitted the only report of this bird. No alternates were present to vote.