Western or Whiskered Screech-Owl? (1 Viewer)

[GuyScharf]

I saw this Screech-Owl last month at the Arizona Sonora Desert Museum, near Tucson, Arizona. The bird is wild, not part of the museum collection. The owl was perched on some kind of vine against a wall.

I'm trying to decide which kind of Screech-Owl this is. Both are found in this area.

Thanks.

Guy

 

[Rasmus Boegh]

The pale greenish bill generally is good for Whiskered, while mainly dark bill generally is Western. Exceptions to this rule are known, but on the other hand it is one of the few things you can actually check on non-vocalizing bird.

 

[GuyScharf]

The pale greenish bill generally is good for Whiskered, while mainly dark bill generally is Western. Exceptions to this rule are known, but on the other hand it is one of the few things you can actually check on non-vocalizing bird.

Thanks! I was leaning towards the Whiskered from what I read in Sibley's, but since I hadn't seen either before, I wanted another opinion.

 

[crispycreme]

According to the Arizona/New Mexico birding mailing list, it's a Western (if it's the same bird):

I attended an early morning meeting at the Desert Museum before coming
to work today, and a Western Screech-Owl was on a very visible roost
from 8:00 am until I left the museum at 9:15 am. Dozens of people
walked by and observed the owl during that time. A Western Screech-Owl
has spent most of the day there on several occasions over the past
month, but today was the first time I was there to see it. It was
perched on a trellis for passion vines along the gallery wall. The
purple gallery wall is on the path between the hummingbird aviary and
the restaurant complex. There are several trellises and it was on the
one farthest from the hummingbird aviary.

- Rick Taylor, Borderland Tours, Wed, 5 Jan 2005

But both Arwen and myself keep seeing this as a Whiskered, based on bill color, heavy cross-barring, and even a bit of whiskering around the facial disc. Just because it appears to be in the same spot as the Western from two months ago doesn't mean it's the same bird now.

 

[GuyScharf]

According to the Arizona/New Mexico birding mailing list, it's a Western (if it's the same bird):

But both Arwen and myself keep seeing this as a Whiskered, based on bill color, heavy cross-barring, and even a bit of whiskering around the facial disc. Just because it appears to be in the same spot as the Western from two months ago doesn't mean it's the same bird now.

The description of the January 5th sighting is at the identical location. I photographed the bird shortly after 2 p.m. on February 14th. I'll search the archives of the list and see what other references I can find.

I find it quite amazing that a bird would roost in the same location, where visitors could literally reach out and touch it, for months!

Guy

 

[Rasmus Boegh]

According to the Arizona/New Mexico birding mailing list, it's a Western (if it's the same bird):

But both Arwen and myself keep seeing this as a Whiskered, based on bill color, heavy cross-barring, and even a bit of whiskering around the facial disc. Just because it appears to be in the same spot as the Western from two months ago doesn't mean it's the same bird now.

Well, I guess we agree! Just out of pure curiosity - how was the "original individual" seen by previous groups ID'ed as being a Western? Assuming it is the same (which is likely, but of course not certain in any way) all features visible point to Whiskered. Unless it actually was heard calling as a Western I see absolutely no arguments for it being that species. Having said that - as mentioned in my previous post - to my knowledge all visible features that can be judged from a photo are only indications and not absolutely certain. Exception being certain morphs, total size (only useful if having extensive experiance with these species and even then somewhat uncertain) and a few additional measurements (only useful in hand).

 

[GuyScharf]

I spent some time studying the four photos I have and reading. I'm still not sure!

I'm attaching two photos. In the first one, I've taken the same photo and adjusted the white balance to be, I think, more accurate. I don't have anything solid to set the white balance to, so chose some of the white on the owl. The background looks now to be a more plausible color for the wall.

Second, I've extracted just the whiskers, or what I think are the whiskers, in a 100% crop. Since I've never seen either a Western or Whiskered Screech-Owl, I'm not sure this is what the whiskers are!

Guy

 

[crispycreme]

Well, I guess we agree!

It's always sensible to be on Rasmus's side of an ID argument!

Guy, those are indeed the whiskers I was talking about too, although like you I'm not 100% sure which ones the name refers to, and some books hint that it's instead refering to the heavier feathering around the beak (but even in that case this bird suggests a Whiskered).


(edit to follow up on another question by Rasmus)

Just out of pure curiosity - how was the "original individual" seen by previous groups ID'ed as being a Western? Assuming it is the same (which is likely, but of course not certain in any way) all features visible point to Whiskered. Unless it actually was heard calling as a Western I see absolutely no arguments for it being that species.

Unfortunately, from what I could tell, this sighting was never followed up on (until now) or challenged on the AZ/NM Mailing List, so only those who were actually on that tour could answer the question for you. I'm only going by field guide descriptions and web photos, whereas birding tour guides should have far more familiarity with these critters.

 

[Andy Bright]

If it is a Whiskered, then it will be very welcome in the birdforum species database

 

[crispycreme]

Just for comparison, here's a Western (photographed in northern California, thus ensuring the species ):

http://www.birdforum.net/pp_gallery/showphoto.php/photo/28231/sort/1/cat/all/page/1


Interesting that the beak is almost the exact same color as Guy's, but at least the breast pattern is much more as a Western's should be.

 

[dacol]

I saw this Screech-Owl last month at the Arizona Sonora Desert Museum, near Tucson, Arizona. The bird is wild, not part of the museum collection. The owl was perched on some kind of vine against a wall.
I'm trying to decide which kind of Screech-Owl this is. Both are found in this area.

I have never seen either one but I would like to play devil's advocate in order to make this discussion more interesting.

Looking at the photo I notice that the bird in the photo has two characteristics that would point it towards Western Sc.-Owl. One is the buffy tinge that is present throughout the front of the bird, eyebrows, neck, shoulders, the dark streaks. compare this with Sibley's drawing of the adult "Mojave" race [Sibley does not use the subspecies names]. The other feature is the nature of the streaking in the chest and belly that seems to be rather continuous instead of the more spotted appearance in the very gray Whiskered Sc.-Owl.

Dalcio

 

[GuyScharf]

I have never seen either one but I would like to play devil's advocate in order to make this discussion more interesting.

Looking at the photo I notice that the bird in the photo has two characteristics that would point it towards Western Sc.-Owl. One is the buffy tinge that is present throughout the front of the bird, eyebrows, neck, shoulders, the dark streaks. compare this with Sibley's drawing of the adult "Mojave" race [Sibley does not use the subspecies names]. The other feature is the nature of the streaking in the chest and belly that seems to be rather continuous instead of the more spotted appearance in the very gray Whiskered Sc.-Owl.

Dalcio

I'm not sure I would trust a "buffy tinge." That could be a white balance problem in the photo.

I think the Western race that would be present in the Tucson area would be the Mexican, not Mojave, race. And the Mexican race sure looks a lot like the Whiskered Screech-Owl!

I am now leaning towards the Western identification for several reasons. In Sibley's, the Western is drawn as having a whiter area in the center of the breast and the Whiskered is not. My photo shows a whiter area. I am also now seeing the stripes as looking more Western than Whiskered.

Regarding the January sighting, it wasn't clear to me from the original mailing list entry whether the sighting was by Rick Taylor or Barbara Bickel, who seems to use the same email address. If by Rick, then I would probably accept the identification as he wrote the book on SE Arizona birding--"Birders Guide to Southeast Arizona". We used that book on our trip; I just didn't recognize his name until now.

I'll ask Rick about the bird I saw and how you tell the two Screech-Owls apart.

 

[Rasmus Boegh]

I'll ask Rick about the bird I saw and how you tell the two Screech-Owls apart.

From what I know, there are several things indicating species, but the problem is that exceptions are frequent (as mentioned earlier). E.g. the greenish bill indicate Whiskered, but some Western have a greenish bills awell (rather than the usual dark). Most Whiskered have more striking markings below, but exceptions exist. Furthermore, Western is larger than Whiskered, but again there is a small area of overlap. To my knowledge the single certain way of differentiating the two is voice. It should be mentioned that lenght of tarsus and bill supposedly are considered certain features as well, but this is obviously completely useless to the usual birder. Of course there's the red morphs, but that's a completely different story. Unless something new has been discovered within the last 5-8 years or so, I feel fairly confident saying that (sadly) are the frustrating facts about differentiating these two Screech-Owls. If Rick forwards any other hints, I'm sure everybody (myself included) would appreciate a line or two in this thread...

 

[dacol]

I'm not sure I would trust a "buffy tinge." That could be a white balance problem in the photo.

I think the Western race that would be present in the Tucson area would be the Mexican, not Mojave, race. And the Mexican race sure looks a lot like the Whiskered Screech-Owl!

I know the Mojave is in California. What I meant and articulated very poorly is that the bird in your photo looked to me paler than the illustrations in Sibley for both the Whiskered SO and other Western SO forms. I read somewhere, but cant remember where, that Western SO in desert areas are lighter colored than other forms. I have not seen any similar remark regarding Whiskered. And also the shape and thickness of the striping which you also note below.

I am now leaning towards the Western identification for several reasons. In Sibley's, the Western is drawn as having a whiter area in the center of the breast and the Whiskered is not. My photo shows a whiter area. I am also now seeing the stripes as looking more Western than Whiskered.

Good points.

Dalcio

 

[GuyScharf]

Probably Western Screech-Owl, Mexican Race

I heard back from Barbara Bickell, who saw what was probably the same owl on January 5th and 12th. She said:

I must admit I didn't look at the owl very critically when I saw it on Jan. 5. A Western Screech-Owl was listed in our docent office as being seen at the museum several times previously. Interestingly, I saw "the" screech-owl again the following Monday (my regular docent day at the Museum). It was perched in a palm tree in the Desert Garden, and was being mobbed by a hummer. I looked at it several times during the day, and was struck by the light-colored bill. I even talked to one of the staff members about the possibility of Whiskered Screech-Owl. I looked at several Westerns in our collection, and at least one of the bills looked fairly light to me. I decided I couldn't really tell them apart. If Rick had been in town, I'm sure I would have asked him to come out and give it a look. I personally separate them by voice, so that only works when calling, and generally by elevation. I wondered if the owl could be a Whiskered that descended to the valley for the winter

Rick Taylor didn't see the bird himself. He told me:

So far as I know in our area only Whiskered Screech-Owls ever show a green(ish) bill, a feature that was evident in your 1st photo. If you have other photos, you might also check foot size. Whiskered has small feet compared to Western Screech-Owl.

I'm not sure I would call the bill "greenish" myself. If it's greenish, it is very subtle--subtle enough that it could be an artifact of the camera's white balance or blue light from the sky.

I spent some time comparing the photo to Sibley's as I noted in a previous message.

I am now leaning towards the Western identification for several reasons. In Sibley's, the Western is drawn as having a whiter area in the center of the breast and the Whiskered is not. My photo shows a whiter area. I am also now seeing the stripes as looking more Western than Whiskered.

I looked at the descriptions of both Western and Whiskered Screech-Owl on natureserve.org. About the Whiskered Screech-Owl, they say:

Habitat Comments: Dense oak and oak-pine woodlands. Subtropical and lower Temperate zones. Usually found at higher elevations where range overlaps western screech-owl (National Geographic Society 1983). Nests in a natural tree cavity or an abandoned woodpecker hole. Nest trees in Arizona include oak, walnut, sycamore, and juniper.

Food Comments: Feeds mainly on insects (e.g., moths, mantises, grasshoppers, beetles); prey length size often about 15 mm (range 6-75 mm).

And for the Western Screech-Owl:

Habitat Comments: Woodland, especially broadleaf (e.g. oak) and riparian woodland, and scrub (Subtropical and Temperate zones) (AOU 1983). Also moist coniferous forest and woodland on northwest coast. Usually found at lower elevations, where in southwest range overlaps with Whiskered Screech-owl (National Geographic Society 1983).

Nests in natural tree cavity or an abandoned woodpecker hole, including holes in saguaro cactus. Readily nest in nest boxes.

Food Comments: Feeds mainly on small mammals (mice and shrews), insects, birds; sometimes also other small vertebrates. Diet may vary seasonally and geographically, depending on local prey abundance.

The Arizona-Sonora Desert Museum is definitely in the desert -- and not in dense oak and oak-pine woodlands. The tallest plants around are the Sahuaro Cactus. The museum is also at a much lower elevation than birding guides say the Whiskered Screech-Owl can be found in Arizona.

If it is a Whiskered Screech-Owl, it is definitely not in its normal habitat.

Today I just get an email back from the Museum staff about this Screech-Owl. They said:

This is a Western Screech Owl, Otus kennicottii. The Whiskered Screech Owl is found at higher elevations around here, in the pine-oak woodlands. We do occassionally get some higher elevation birds on grounds, but their stays are usually pretty short, and this little owl has been here for a couple of months now. I am glad you enjoyed your visit. If you have any other questions, please write again.

No one has said "this is a X Screech-Owl because Y...." However, I think the preponderance of the evidence says that in all likelihood this is a Western Screech-Owl of the Mexican race.

I appreciate everyone's comments and have learned a lot. I'll surely look much more closely at the next Screech-Owl that I see!

 

[crispycreme]

I expect it's probably a Western too, based on possibilities and likelihoods. Although, due to abundant water (and presumably prey), I wouldn't consider the Desert Museum to be "normal" in terms of environment and habitat. But I too have spent a bit of time poring over pics, and reading various texts, and there's more than a few instances of Westerns having a near-identical bill color to the one displayed here. I'm still seeing the breast pattern as more Whisker-ishy, but until I get to compare the two patterns upfront and personally (hopefully this upcoming May as we head down towards Portal), I'm certainly not qualified to call it based on that criterion.

(I do find it interesting that a few people seem willing to ID it based simply on the fact that it's the bird that's "supposed" to be there. Not me! No, never! )

One thing I don't hear much talked about is the amount of whiskers on other Otus owls. From what I understand, they're not intended to be used as an ID because they're normally so hard to see. But there's got to be a reason the Whiskered is called a Whiskered - presumably because it's got whiskers, as this bird seems to have. I'd be interested to know how they contrast to those found on the Western and Eastern (if they have 'em at all).