Proposal (1014) to South American Classification Committee

Treat Dacnis egregia as a separate species from Dacnis lineata

Note: This is a high-priority issue for WGAC. Back in 2004, we rejected a proposal (SACC 103) on this proposed split, but that was so long ago, and SACC membership has changed so much that another look is warranted. Also, rather than making this “103.x” and the turbulence that would cause in the voting charts, I’m going to give this one a new number, but also plug in most of the text from SACC 103.

Background: Our SACC note on this is as follows:

40. Ridgely & Tudor (1989) pointed out the trans-Andean egregia group may deserve species rank. Ridgely et al. (2001) considered egregia a species separate from lineata based on plumage differences and disjunct range. SACC proposal to recognize Dacnis egregia as a separate species did not pass because of insufficient published data. Hilty (2011) and Del Hoyo & Collar (2014) treated egregia as a separate species, “Yellow-tufted Dacnis.”

I repeat below the text of the proposal I wrote in 2004 along with voter comments:

Proposal (103) to South American Classification Committee

Recognize Dacnis egregia as a separate species from D. lineata

Effect on South American CL: This proposal would split our Dacnis lineata into two species, with recognition of Trans-Andean egregia group as a separate species.

Background: The bird we treat as one species, Dacnis lineata (Black-faced Dacnis), has three disjunct subspecies: (1) the subspecies egregia in the Cauca and Magdalena valleys of Colombia; (2) the subspecies aequatorialis in western Ecuador, and (3) nominate lineata in most of Amazonia. This is the traditional classification (e.g., Hellmayr 1935, Meyer de Schauensee 1966, 1970, Storer 1970, Meyer de Schauensee & Phelps 1978, Hilty & Brown 1986, Isler & Isler 1987, Ridgely & Tudor 1989, Sibley & Monroe 1990).

The Amazonian population has a white belly, undertail coverts, underwing coverts, and mostly concealed white feathers at sides of breast, whereas in the other two all these areas are yellow; nominate birds are also slightly bluer, less greenish blue. The plumage patterns are extremely similar if not identical except that the egregia group evidently has more extensively contrasting areas on breast to the point that the yellow is clearly evident at the sides of the breast in the field (as illustrated in Hilty & Brown 1986, Ridgely & Greenfield 2001). Hilty & Brown (1986) indicate that egregia and aequatorialis differ in that the latter's belly was more deeply yellow and that the blue-green colorations was evidently greener. Females also differ slightly between the two groups, with nominate birds having whiter, less yellowish, bellies.

New information: Ridgely & Greenfield (2001) treated egregia group as a separate species, with the following note:

"Trans-Andean D. egregia is regarded as a species distinct from cis-Andean D. lineata (Black-faced Dacnis), based on its striking plumage differences and disjunct range."

Analysis: The only plumage difference that might be associated with a "species-level difference" is the more extensively yellow sides of the egregia group, emphasized by Ridgely & Greenfield's English name, "Yellow-tufted Dacnis." There are no qualitative vocal descriptions for comparison or any other relevant information that I could find.

By comparison in a congener, trans-Andean D. cayana baudoana differs much more from other D. cayana taxa than these subspecies of D. lineata do from one another, and are furthermore likely to be parapatric or nearly so; thus, one could build a better case for a split there than in D. lineata. Bob and others often use "disjunct" distribution as evidence for separate species status. I point out again that "disjunct" involves a continuum from separation by a few kilometers (as in river-barrier cases) to thousands of km, with no way that I can see to decide "how disjunct" two populations need to be to be considered separate species. In contrast, I would emphasize the opposite, namely that parapatry with no evidence of gene flow provides definitive evidence for species rank (as perhaps in the baudoana example above).

Recommendation: I vote "NO" on this proposal. Several other similar "splits" have at least been accompanied by qualitative vocal descriptions. This one rests completely on whether the yellow patches at the sides of the breast merit species rank; they are indeed suggestive, but it need to be convinced.

Partial Literature Cited:

HELLMAYR, C. E. 1935. Catalogue of birds of the Americas. Field Mus. Nat. Hist. Publ., Zool. Ser., vol. 13., pt. 8.

HILTY, S. L., AND W. L. BROWN. 1986. A guide to the birds of Colombia. Princeton University Press, Princeton, New Jersey.

MEYER DE SCHAUENSEE, R. 1966. The species of birds of South America and their distribution. Livingston Publishing Co., Narberth, Pennsylvania.

MEYER DE SCHAUENSEE, R. 1970. A guide to the birds of South America. Livingston Publishing Co., Wynnewood, Pennsylvania.

RIDGELY , R. S., AND P. J. GREENFIELD. 2001. The birds of Ecuador. Vol. II. Field guide. Cornell University Press, Ithaca, New York.

RIDGELY, R. S., AND G. TUDOR. 1989. The birds of South America, vol. 1. Univ. Texas Press, Austin.

SIBLEY, C. G., AND B. L. MONROE, JR. 1990. Distribution and taxonomy of birds of the World. Yale University Press, New Haven, Connecticut.

STORER, R. W. 1970. Subfamily Thraupinae. Pp. 246-408 in "Check-list of birds of the World, Vol. 13" (Paynter R. A., Jr., ed.). Museum of Comparative Zoology, Cambridge, Massachusetts.

Van Remsen, February 2004

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Comments from Robbins: "NO. Clearly, more information is needed on the entire complex before any changes should be made."

Comments from Zimmer: "NO. Published evidence still too weak in my estimation."

Comments from Stiles: "NO, more real evidence required (voice, genetics, morphometrics, etc.) - when this evidence is published, we´ll see if a split is warranted."

Comments from Nores: "NO. El pattern the color tan particular y casi idéntico entre las poblaciones cis y transandinas sugieren para mi subespecie y no especies, y sería importante esperar estudios genéticos."

Comments from Jaramillo: "NO. I bet that further work will reveal that a split is fine, but until that oft mentioned "further work" is done."

Comments from Schulenberg: "NO. I don't know how one would "know", under a biological species concept, what these plumage differences represent in the case of two taxa that are allopatric. Surely some other type of evidence should be brought to bear. Striking phylogenetic species, of course.”

Additional information: From Hellmayr (1935) The isolated Chocó subspecies aequatorialis “Very similar to D. 1. egregia, but plumage of male, especially humeral area, rump, and under parts, decidedly more greenish with the under wing coverts and abdominal patch of a richer yellow; female with throat and foreneck more grayish, thus pointing to D. I. lineata.” [note to self – double-check this because photos suggest opposite] I think here we have part of the logic for continuing treatment of egregia as a subspecies in the observation that the grayer throat and neck of aequatorialis is intermediate between egregia and lineata. Keep in mind that in Hellmayr’s era trinomials were still somewhat relatively new, and that a lot of early taxonomists like him, Ridgway, and Cory were in the process of making ties among taxa described as species in an era when broad comparisons among specimens, much less images, was difficult.

New information: Hilty (2011) also treated egregia (with aequatorialis) as a separate species from D. lineata, but mentioned only the plumage differences between the two and their disjunct ranges (more on that below). Here is the HBW plate by Hilary Burn:

Del Hoyo & Collar (2014) treated whitelyi and cyanoptera as a separate species based on the Tobias et al. point scheme as follows (provided by Pam Rasmussen):

" Often treated as conspecific with D. lineata, but although main call note seems to be identical (1) it differs in its turquoise-green vs turquoise-blue crown and most of underparts (2); yellow vs white mid-belly to vent (3); and yellow pectoral tufts vs none (3). Two subspecies recognized."

Thus, the threshold 7 points was achieved strictly on plumage characters.

The advent of the Macaulay Library at CLO opens up a new world for appreciation of bird colors, patterns, and shapes. At the urging of Pam Rasmussen, I looked at virtually all the useful photos of lineata, egregia, and aequatorialis. What is clear to me now is why Bob and Steve elevated this taxon to species rank, although they didn’t elaborate on this the way one can now with photos. As Pam told me, these two groups have different looks. The yellow tufts at the side of the breast and the bend of the wing may qualify as structural differences. They are in-your-face conspicuous when you see photos of live birds – they appear to be displaying them somewhat. This is very different from nominate egregia, in which not even a hint of white underwing shows in most photos. Further, that yellow in the center of the belly isn’t some pale shade of yellow but an intense, brilliant one that matches the tuft color – these two color patches really set off the blue of the rest of the underparts that imparts a “look” very different from nominate lineata. As a canopy bird, that yellow belly is particularly conspicuous. The interaction of the yellow-blue-yellow as a strong signal is striking to me, as a human:

egregia from N. Colombia by Guillermo NAGY Aramacao Tours:

aequatorialis from Nariño by Javier Fernando Dominguez Trujillo and Manabí by Emily Larson:

And for comparison here is lineata, from Napo by Jian Mei and from La Paz by Tini & Jacob Wijpkema:

Female egregia are more yellowish green than the grayish olive of female lineata, as you can see in the plate above and here in some LSUMZ specimens:

Discussion and Recommendation: There are good reasons to vote NO on this one, as in the prior proposal. There are no data on voice. There are no published data that I know of on genetic

differences, but as you have come to expect from me, these would be of limited use in my opinion in assessing taxon rank for these allotaxa. [note to self – check Burns lab phylogenies to see what taxa sampled, including also hartlaubi and albiventris]. In the original proposal, I discussed the problem of using “disjunct” ranges as something by which to assign taxon rank, and I stand by those words, and also add that if we applied that criterion in this case, then aequatorialis should also be considered a separate species from egregia.

But I just can’t get past the structural/plumage differences between these two. Without a hint of relevant data, I would argue that if appearance has anything to do with mate choice, then these two lineages have diverged past the point of no return. The pectoral tuft is not shown by any other Dacnis or close relatives. This is not the same as having a difference in color, in my opinion, but a quantum difference from any reasonably related tanager that I can think of. This argument is entirely subjective, but it squeezes out of me begrudgingly a recommendation for a YES (for which I will likely pay a price in the future for being inconsistent). Mark Robbins pointed out that perhaps no one has photos of nominate lineata responding to playback or displaying, and thus perhaps its comparable white is always concealed, although I saw no indication of this in the hundred or so photos I looked at sorted by Best Quality. [note to self – go all the way through lineata in Macaulay]. Maybe one of you know the answer to this.

English names: BirdLife International retained “Black-faced” for more widespread lineata and used “Yellow-tufted” for egregia. The latter is as good as it gets for an English name, and it has two decades of traction. So, if the proposal passes, I see no reason not to adopt the name, i.e., no proposal needed. The use of a parent name for the widespread daughter is one of our SACC guidelines. If anyone feels different, speak up and be prepared to write the proposal.

References: (see SACC Bibliography for standard references)

Van Remsen, June 2024

Comments from Robbins: YES. After seeing those stunning photos of egregia, I contacted Steve Hilty (he will officially weigh-in) and Iván Lau (who has extensive experience with it and nominate in Colombia), to find out if the prevalence of the tufts in those photos might be the result of playback: here is what Iván said: "egregia has always very visible yellow tufts and haven't seen any change with playback (is not especially responsive to playback.)" I think everyone believes those tufts may be important in courtship and perhaps aggressive/territorial encounters. So, although these taxa are allopatric, I believe if they were in contact those striking differences in plumage likely would resort in assortative mating, i.e., species recognition. Thus, I'm now voting to treat egregia as a species.”

Comments from Jaramillo: “YES – before getting to the bottom of the proposal, I looked at photos of these birds and independently came to the conclusion made at the bottom of the proposal. That is, that the yellow tufts are structurally different, held in a flared manner and give those birds an entirely different aspect when compared to lineata. Coloration is of importance in mate choice and species recognition in brightly colored birds, at least usually. But a structural feature, that suggests a display function to me is a notch higher than mere coloration differences. This along with the plumage color differences, disjunction and the pattern that we see frequently with lowland species on either side of the Andes when studied in detail makes me comfortable accepting these two as species.”

Comments from Areta: “NO. The differences seem largely explained by a difference of yellow pigmentation (and, to some degree of the size of the lateral "tufts", being larger and therefore more evident in egregia, but ALSO present in reduced form in lineata). Calls seem identical. I would like to see more sources of evidence in favour of a split, which I don´t deny might be good, but for which data is scant beyond the obvious plumage differences of unknown mating value. In a phylogenetic study, the sister species of D. lineata was found to be D. viguieri (though support is poor), which looks quite different (see Price-Waldman 2019 https://digitallibrary.sdsu.edu/islandora/object/sdsu%3A28660).”

Comments from Lane: “YES. I’m pretty ambivalent on this one, but a tempered YES given the fact that both male and female plumages are saturated with yellows, so both are easily distinguished from D. lineata (as opposed to simply a different male plumage). This is a rather narrow call, though, so I can be persuaded to go the other way if others seem to be unimpressed by the distinctions.”

Comments from Claramunt: “YES. I would be comfortable with separating these two based on the difference between yellow versus white alone. The additional difference in the lateral tufts proves that this is not a case of just a single difference in pigmentation and there is more going on.”