Part 5: Mouth lining, calls, and behavior
text © 2003 Don Roberson
all photographs are copyrighted © 2003
by the photographers cited; used here with permission

MOUTH LINING: Lanyon (1961) said that this "is the most practical and most reliable morphological criterion for the specific identification of fresh specimens of this complex." Sounds promising! He "found no evidence that the character varies geographically or sexually in either species. In my series of 50 specimens of known voice, there was 100 per cent agreement between the specific determination based solely on color of mouth linings and those based on certain diagnostic vocal patterns." Nutting's has "orange-colored mouth linings." All fresh Ash-throated specimens had "'flesh-colored' mouth linings ('pale ochraceous buff' of Ridgway 1912)." He concludes by noting that Nutting's groups with Great Crested and Dusky-capped on mouth lining color, while Ash-throated groups with Brown-crested. Lanyon's mouth-lining character has been cited over and over in the literature as diagnostic.

Just reading the above, however, raises some questions. Does his "series of 50 specimens of known voice" imply there were a maximum of just 25 of each species? If so, that is a fairly small series compared with the over 400 specimens he used to develop his tail pattern key. Secondly, although he found no geographic or sexual differences, he doesn't mention age-related distinctions at all. His study was primarily focused on the question: "is Nutting's a good species?" (he found it was). But it is clear he focused on birds on territory in other words, the evidence suggests very strongly that his 50 specimens were all adults on the breeding grounds. Thus he does not answer the question: is there age-related variation in mouth lining color?

This is an important question. Cardiff & Dittmann (2000), writing about Brown-crested Flycatcher and discussing its separation from Great Crested, describe mouth linings. As we have seen above, Nutting's is said to group with Great Crested and have orange mouth linings, while Ash-throated groups with Brown-crested with flesh-colored linings. Cardiff & Dittmann write that "not all [Great Crested] have bright orange-yellow [mouth linings]; LSU specimen data (described as flesh, dull-yellow, and dull yellowish-tan; these atypical mouth colors may pertain to first-year birds, but more data needed);" [emphasis added].

If it is possible that the bright orange mouth linings of Great Crested can be dull yellow or flesh-colored in first-year birds, is it possible that the same may be true in Nutting's? Given this question for which there is no data I don't see how anyone can conclude that mouth lining color will diagnostically identify the Santa Cruz bird, since we know for a fact that it is a first-winter bird.

Further, mouth lining color variation also goes the other direction. There are specimens of Ash-throated Flycatcher whose data tags state the mouth lining was "orange" (Bowers & Dunning 1987, cited with approval by Cardiff & Dittmann 2002).

Bowers & Dunning (1987) published a widely-read paper in American Birds on a bird they had captured and banded in Santa Cruz Co., Arizona, on 15 July 1985 (not to be confused with Santa Cruz Co., California; all reference to "the Santa Cruz bird" in these pages is to the California bird). They identified it as a Nutting's, and published both photos of it and comparative material. The bird was heavily worn and called only once upon extraction from the net; the identification as Nutting's relied heavily on the presence of orange mouth linings. This identification is now considered controversial (Cardiff & Dittmann 2002); there is an on-line statement that the Arizona Bird Records Committee thinks it likely a worn Ash-throated (although they have never reviewed the record). If it is an Ash-throated, this is another orange-mouthed Ash-throat beyond the specimen cited by Bowers & Dunning (1987).

I noticed some interesting points in reviewing the published photos; I have scanned the relevant pages and reproduce R.W. Bower's photos here (fair use doctrine; these shots are published at Amer. Birds 41: 8 & 9).

The first shot (near right) is an Ash-throated that is stated to have "pink" mouth lining. The second (far right) is the mystery bird, considered Nutting's in the article, stated to have "orange" mouth lining. I don't see anything that is nearly that simple. First, the tongues of both birds are bright pink. Second, the color inside the lower mandible on both birds is a really dull straw color. The "mouth lining" itself must refer to the lining deeper in the mouth and (maybe) inside the upper mandible, but it cannot mean the tongue or the inside of the lower mandible.
The concept that the term mouth lining cannot mean either (a) the tongue or (b) the lining of the inside of the lower mandible is supported by discussion in Pyle (1997). In discussing young birds (p. 19) he says that "The inside of the mouth, including the 'roof' (upper mandible lining) also is brighter in tone and/or paler in hue in juveniles than in adults." Since he does not include the "floor" (lower mandible lining) in this statement, the clear implication is that the color of the lining of the lower mandible is not a feature of the "mouth lining" and is not a useful character. Pyle also says that "more study is needed on changes in the color of the roof of the mouth in these and other species." Inconsistent with my concept is the fact that recent Birds of North America fascicles (e.g., Cardiff & Dittmann 2000, 2002) do not distinguish between the "tongue" and the "mouth lining" in their descriptions of soft parts. However, it is undeniable that Ash-throated may have a bright pink tongue (photo above) and so tongue color is not a key.

The key point on mouth lining is the color inside the actual mouth itself, including (perhaps) the "roof" (upper mandible lining) but excluding the lower mandible lining, and (probably) excluding the tongue. Below is a series of four video-caps (© Joel Weintraub) of the Orange Co., southern California, Nutting's:

Here is what I see: left photo was a bright pink mouth (maybe due to the tongue and/or the angle, next is bright orange, third is bright orange (particularly the upper mandible lining), and the last shows only the lower mandible lining, which is a dull yellowish color, maybe called "flesh." Do you agree with this color analysis? There will be a bit more on that below.

If the key point is the actual color of the inside of the mouth and upper mandible only, what colors should we see? As discussed above with reference to Lanyon (1961), Nutting's is orange while Ash-throated has "'flesh-colored' mouth linings ('pale ochraceous buff' of Ridgway 1912)." Cardiff & Dittmann (2002) describe Ash-throated mouth lining as "usually flesh-colored, occasionally yellowish flesh to dull yellowish, rarely orange." Please note the absence of any reference to pink, let alone bright pink, by any of these authorities. The only reference to "pink" in Ash-throated that I find is in Bowers & Dunning (1987), and I suspect it is a reference to the tongue. Look at their in-hand photo of their undeniable Ash-throated, reproduced above. The tongue is pink, the bottom of the lower mandible is a really dull straw, but there is a tiny bit of the mouth lining itself shown just inside the gape and right of the tongue. It looks dull yellowish to me, and that color is consistent with the literature descriptions. You can go check up on "pale ochraceous buff" yourself at an online color chart; as shown there, it is the equivalent of pale yellowish-pink. It is rather like the color of the inside of the lower mandible on the in-hand pictures, above. It is sort-of like the color of the back of your hand if you are Caucasian and not tanned or sunburnt. It is not anything like bright pink. So we want to see if the Santa Cruz bird has a dull mouth-lining that is flesh-colored or pale yellowish-pink (=flesh), or a bright orange mouth lining that can look bright pink in some views (e.g., the Orange County bird, left hand shot above).

To help this analysis, I have used the PhotoShop color picker on the four shots of the Orange County bird, and then created a box with that color in the lower left of each photo, and then have done the same with the photos I can find of the Santa Cruz bird. I try to choose the color in the very center of splash of color and away from edges or shadows:

Orange Co. Nutting's [photos © Joel Weintraub]
Santa Cruz bird [photo near right © Cindy Cummings; far right © Peter LaTourrette]
No photos show this same angle but described as bright orange but most observers
No photos show this same angle but described as bright orange but most observers
Note that when the lighting was good and direct, and the 'roof' (upper mandible lining) was well seen, the Orange County bird had a bright orange mouth lining, confirmed by the mechanical ("objective") color picker. And, as we would expect, the color of the lower mandible lining is a dull yellowish-pink (=flesh), recalling that the lower mandible lining is not part of the "mouth lining" color to be analyzed. In the Santa Cruz bird, the bottom row, far right, photo shows the bird eating an olive. We can see a bright pink tongue and a dull yellowish lining to the lower mandible, just as we would expect for either species. This is not a helpful photo for distinguishing between the species (although it is a really nice shot for behavior!).

So that brings us to the leftmost photo in each row. To my eye, both photos looked to have bright pink mouth linings deep inside the mouth and inside the upper mandible. I don't think the tongue is in the way. Yet the "objective" color picture shows those colors to be a dark maroon! I think this means that the actual color is somewhat shaded in these shots and our eyes automatically adapt for that shading to see a bright pink. I added a box that the color picker chose as the color of the primary edges to test Cindy Cumming's photo, and it looks "in the ballpark" for the right color, although tending a bit too brown. There is a remarkable similarity in the tone of color chosen by the color picker between the lefthand shots of both the Orange Co. and Santa Cruz birds. We are missing photos of the Santa Cruz bird with the proper angle of direct light, but, given the experience with the southern California photos, I would not be at all surprised to find they would show bright orange. In any event, I hope we can all agree that Cindy Cumming's photo shows a bird with brightly colored mouth linings, not dull colored.

Incidentally, most observers of the Santa Cruz bird describe the mouth lining as orange. But what are they describing? My view was facing the bird as it ate an olive, I believe the tongue was below the olive, and I believe I described the color of the upper mandible lining, just as shown in the photos of the Orange Co. bird, center shots.

Is there a possibility that those who have described a "flesh-colored" mouth lining were looking at the lining of the lower mandible, as in the bottom row, far right, photo above? You can determine whether that is a possibility, and whether you want to give any weight to the descriptions of "orange" mouth lining from various other observers.

VOCALIZATIONS: In reviewing the literature, I notice three interesting points about vocalizations among the Myiarchus flycatchers in the group that is comprised of Nutting's, Ash-throated, Brown-crested, and Great Crested Flycatchers:

The most thorough evaluations of the vocalizations of these groups are Lanyon's (1961) study [Ash-throated and Nutting's] and the Bird of North America fascicles on Great Crested (Lanyon 1997), Brown-crested (Cardiff & Dittmann 2000), and Ash-throated (2002). All these major works include spectrograms of all the calls. Lanyon (1997) says that playback experiments with both Great Crested and Brown-crested "clearly demonstrate an ability of each species to discriminate between their vocal repertoires and to respond positively only to their own." Lanyon (1961) showed that the vocalizations of Ash-throated and Nutting's were inherent from fledging, hard-wired (as it were) and not learned (thus unlike sparrows and warblers and other nine-primaried passerines who learn their vocalizations from hearing their parents and neighbors while very young).

In the following chart, I've tried to condense what this literature has to say about vocalizations, lining up similar ones in the same row. All authors recognize that the birds have "diagnostic" calls and other non diagnostic calls that are similar to other species (but apparently the birds can tell even these apart). Both sexes give the four basic calls; there are combination of calls in Ash-throated and Nutting's that extend the number of vocalizations to 6 or 7 (Lanyon 1961, Cardiff & Dittmann 2002). There are also male only dawn songs on the breeding grounds that I do not consider here.

Great Crested
huit, can be written wit-whit
huit (most frequent call)
(Howell & Webb 1994, 1995 describe this as a wet to slightly sharp pip or pic, often quite soft)
pit-peer (Lanyon); unclear if the pit can be given alone
This is a basic huit, wit, whit, pic or pip call that may be very difficult to distinguish between the first 3 species, and possibly the 4th?
burry urg
a low grating note (shown on spectrogram in Lanyon 1961) but not described in words except that is has an Ash-throated counterpart; Will Russell described a low grating note on the Arizona Nutting's
 Hard to grasp this call; Cardiff & Dittmann (2000) considered it a diagnostic call for Brown-crested, thus obviously the quality of the note is important
preeet or purrit
a vibrato whistle
wheer, combined becomes ha-wheer
whee-u (Howell & Webb 1995) but not described in words in Lanyon (1961)
 Apparently rather rare notes, except used in combos, esp. in Ash-throat
rising whee-eep!
whay-burg (emphasis on first syllable)
br-ick, always (?) given in combo as ka-brick (emphasis on second syllable)
whistled peer (Lanyon), perhaps now rendered as a sharp rising wheek (Howell & Webb 1994, 1995)
 This is the diagnostic calls, although the Ash-throat is actually a common combo call, and for now I'll assume that Lanyon's peer is today's wheek! (but I'm not sure of that, and this chart may be in error on that point)
a combo note that is a rolling series of huits
a combo note that is a rapid rolling series, perhaps the wh-ik wh-ik of Howell & Webb (1995)?
This may also be a diagnostic call, at least as to quality, and is one of the extra combo calls detailed for Ash-throat and Nutting's, but not the other two

Although I did some comparing of spectrograms to come up with this summarized chart, it seems likely some points were misinterpreted. Lanyon (1961) did not use words to describe most of his calls, so I tried to find comparative words out of Howell & Webb (1994, 1995) but could have assigned them wrongly. So it is the Nutting's column that is most speculative here.

In addition, Joe Morlan has posted sound files from Chris Benesh and Alvaro Jaramillo that include Nutting's Flycatchers in Mexico. I am personally unable to access those files (no broadband at home, no sound card at work) but those who can do so have found them useful.

Words are a difficult tool to use to describe vocalizations, and most everyone will use different words for the same calls. For example, five of us listening to the Santa Cruz bird on 3 January described the calls this way:

Also, another observer, who thought the call was like an Ash-throated, described it this way: These descriptions (above) describe the standard call often given in a short quick series heard dozens of times over a several hour observation. Note the variation in the descriptions (as might be expected) but also note the similarities. Whatever the call is, it was sharp and whistled. Please also note that it does not seem to nicely fit into any of the descriptions of the four species in the table above. We assume it must be there (do we?) but perhaps the range of variation is wider than thought. Might this particularly apply to Nutting's, the poorest known of the four species? You can be judge of that.

Steve Gerow and David Suddjian spent more time with this bird than anyone else, and they heard two or three other calls, described as follows

To my knowledge, no one has heard a burry call, or a throaty ka-brick, or any of the "typical" Ash-throated calls. You can decide for yourself whether any of descriptions recall the "wet to slightly sharp" whit or huit of Ash-throated. You may also develop an opinion on whether the "sharp, short" whistled pwik or pweep calls are actually a shortened version of a longer wheek call, now considered diagnostic of Nutting's. Could winter calls be different than summer calls in length and intensity? The Arizona Nutting's called most frequently during interactions with a wintering Ash-throated [Will Russell, commentary]. Could the presence of other Myiarchus intensify calling?

BEHAVIOR: One of the immediately curious aspects of the Santa Cruz bird was that it spent most of its time eating olives. It would take them off the olive tree, or, just as frequently, pick them off the ground under the tree. It would "shake it and beat it against a branch or the ground, in a manner of a large flycatcher or tanager dealing with an insect" (to quote David Suddjian), and then swallow them whole. The pit was later regurgitated. "It dropped a number of olives in the process, either by choice or unintentionally. It ate olives that were ripe and firm, as well as those that were over-ripe and partly shriveled;" [D.L. Suddjian]. For some time, it appeared that this was entirely "an olivacecous flycatcher."2

I thought it very odd that a flycatcher in the genus Myiarchus should be fruit-eating (although I was aware that flycatchers of other tropical genera ate fruit regularly). David Suddjian, however, who has spent hours with the bird, also "saw it forage for insects or other invertebrates several times." He estimated the foraging time was split 70% of olives and 30% of insects. He eventually found it also eating berries at a cottoneaster tree.

Both the Nutting's in Arizona and the Nutting's in southern California spent a lot of time eating fruit. However, all 3 North American species of Myiarchus are known to ingest some fruit on their wintering grounds (Lanyon 1997, Cardiff & Dittmann 2000, 2002). While Ash-throated is almost exclusively a carnivore on arthropods in the breeding season, it will eat fruit in migration or the wintering grounds. Vegetable matter was in 13% of 91 stomachs collected in California between April-December (the percentage in winter not quantified; Cardiff & Dittmann 2002).

The other pages in this project are:

[shape, bill size]
[plumage patterns, mouth color, vocalizations]
[rectrix patterns]
[secondary edges, primary projection]
Personal conclusions


1 Later I learned that some "helpfully" retranslated this reference of a cross between a Downy Woodpecker and a Least Flycatcher to conclude the bird gave a standard Ash-throated whit or wit. Actually, we were listening to a Downy calling in the background -- a sharp pik -- and the sharpness of the flycatcher call was in that category, but there was a 'pw' sound, so that's where a throw-away reference to Least Flycatcher came in. The call was much closer to the woodpecker. It had no 'wetness' to it like a call rendered whit or wit would have.

2 Okay, this is a pun. If you don't get it, you are too young. I don't know if puns are worthy of "credit," but this is a David Suddjian pun. [If you are still scratching your head, please recall that Dusky-capped Flycatcher was known as Olivaceous Flycatcher some decades ago (for its color, not diet), and this Santa Cruz bird was first thought to be an Olivaceous, err, Dusky-capped Flycatcher.








Page created 23 Jan-3 Feb 2003