Proposal
(125) to South
American Classification Committee
Split Notharchus
hyperrhynchus from N. macrorhynchos
Effect on South American CL: This
proposal would elevate a taxon to species rank that we currently treat as a
subspecies on our baseline list.
Background: The hyperrhynchus subspecies
group (consisting of named subspecies hyperrhynchus, cryptoleucus, and
paraensis) of Notharchus macrorhynchos (the White-necked
Puffbird) was formerly considered (e.g. Ridgway 1914, Cory 1919) to represent a
separate species from nominate macrorhynchos. Peters (1948) lumped these
forms (and swainsoni) without explanation, into a single
wide-ranging, polytypic species. Most recent compilations (Meyer de Schauensee
1966, 1970; Sibley & Monroe 1990; Clements 2000) have followed suit,
treating Notharchus macrorhynchos as a polytypic species consisting of
five subspecies that ranged from Mexico to Argentina. The 7th Edition of the
AOU Checklist (1998) recognized two subgroups within this species complex: a
wide-ranging macrorhynchos group (consisting of the taxa hyperrhynchus,
cryptoleucus, macrorhynchos, and paraensis), and a geographically
disjunct subspecies swainsoni, which is restricted to the Atlantic
Forest of southeast Brazil, eastern Paraguay and northeastern Argentina. In the
7th Volume of the Handbook of the Birds of the World, Rasmussen and Collar
(2002) elevated swainsoni to separate species status (see SACC
Proposal #124) and synonymized cryptoleucus of El Salvador and Nicaragua
with hyperrhynchus. These authors recognize three subspecies
of N. macrorhynchos as follows:
N. m.
hyperrhynchus (Sclater 1856) - S Mexico south to N & NE Venezuela, and
south to Colombia, Ecuador, E Peru, N Bolivia and W Brazil (E to Rio Tapajós
and S to Mato Grosso).
N. m.
macrorhynchos (Gmelin 1788) - extreme E Venezuela, the Guianas, and
extreme N Brazil south to the Amazon.
N. m.
paraensis (Sassi 1932) - lower Amazon Valley in Brazil (Pará east of
the lower Rio Tapajós and into N Maranhão).
Rasmussen and Collar (2002) noted
that:
"Races hyperrhynchus and paraensis markedly
distinct from nominate, and together may constitute a separate species."
In the Family Account, the same authors remark that "At the same time,
however, it should be noted that the nominate race of the White-necked Puffbird
in the Guianan region is also distinctive in appearance and possibly in song;
thus, further study of the situation is required."
This situation has received
surprisingly little attention from ornithologists or birders, given that
plumage differences between hyperrhynchus/paraensis versus macrorhynchos are
striking. The former group differs from the latter in having a much broader
white forehead (white in nominate is restricted to a narrow frontlet), a
broader white hind-collar, much less extensive black patches on the flanks, and
a noticeably larger bill. These differences are well illustrated in HBW Volume
7. The subspecies paraensis is similar to hyperrhynchus
in plumage characters, but has an even longer bill. The plumage differences
between hyperrhynchus/paraensis and nominate macrorhynchos are of
the same order as the differences between any of these three forms and N. tectus
(Pied Puffbird), N. ordii (Brown-banded Puffbird), and N.
pectoralis (Black-breasted Puffbird), and thus, are consistent with
species-level plumage differences across the rest of the genus.
Vocal differences are even more
pronounced, but no published quantitative analysis exists. In my experience,
the songs of hyperrhynchus and paraensis are virtually identical
and unvarying throughout their wide distributions. This song is described by
Stiles and Skutch (1989) as "a long bubbling trill, at a constant pitch or
rising slightly, then falling" and by Hilty (2003) from Iquitos, Peru as
"a long, nasal, frog-like trill, prrrrrr (up to 15-20
seconds)". Ridgely and Greenfield (2001) describe it as "an evenly
pitched monotonous trill that lasts 3-5 seconds, sometimes given by both
members of a pair". These descriptions fit my own tape recordings of hyperrhynchus
from Chiapas, Mexico; Pacific Slope of Costa Rica; and lowland E Ecuador; as
well as my recordings of paraensis from Mato Grosso and Amazonas,
Brazil. The song of nominate macrorhynchos is very different,
and is described from SE Venezuela by Hilty (2003) as "a long series of
rapid pree whistles (ca. 30 whistles in 8 seconds) on the same
pitch". I have heard nominate birds giving a complex song that begins with
a similar series of whistles (as described by Hilty) that then leads into a
series of terminal couplets, recalling the songs of N. ordii, N.
pectoralis and N. swainsoni. This song is not even remotely like the
trill given by hyperrhynchus/paraensis. Rasmussen and Collar (2002)
described the song of N. macrorhynchos (presumably the nominate form,
although this is not explicitly stated) as being "a very high weak trill
at variable speeds, usually descending, "ui-ui-uiwi-di-dik wi-di-dik
wi-di-dik". Oddly, the first part of this description ("high
weak trill") seems to refer to the song of hyperrhynchus/paraensis,
whereas the transcription that follows sounds more like the song of nominate macrorhynchos.
Hilty (2003) notes the vocal differences between the two groups as follows:
"Song
(mid-morning) in Rio Grande, Bolívar, a long series of rapid pree whistles
(ca. 30 in 8 sec) on same pitch. At dawn (Iquitos, Peru) a long, nasal,
frog-like trill, prrrrrrrrr (up to 15-20 secs) on same pitch,
given once every 2-5 minutes and by both sexes."
Unfortunately, Hilty obscured the
significance of the differences by seemingly suggesting that they may reflect
the difference between dawn songs and regular songs. I have taped hyperrhynchus and paraensis giving
the trilled song at all hours of the day (including mid-day), and, conversely,
I have heard the complex song of nominate macrorhynchos at dawn from
atop canopy towers. Time of day has no bearing on the described vocal differences
between these taxa.
Analysis: The
plumage, biometric (possibly mainly bill length and depth), and vocal
differences between nominate macrorhynchos and hyperrhynchus/paraensis
are comparable to the differences between any of these three taxa and the other
recognized species in the genus. The distributions of the two groups are
seemingly parapatric in Venezuela (between hyperrhynchus and
nominate) and in Brazil along the Amazon (nominate along north bank, paraensis along
south bank), with no reported intergradation. I have no doubts that the vocal
differences alone would act as isolating mechanisms between these taxa were
they to come in contact, and the strong differences in distribution of black
and white on the head and face of the two forms would seemingly also act to
preclude recognition. Based on both vocal differences and morphological
differences, I'm not even certain that macrorhynchos and hyperrhynchus/paraensis are
one another's closest relatives. In song, distribution of black on the head/face,
and in its smaller bill, nominate macrorhynchos is more
reminiscent of N. ordii and N. pectoralis than of hyperrhynchus/paraensis.
The down side of all of this is the
absence of any real published analysis of either vocal or morphological characters.
However, qualitative descriptions of both types of characters are in the
literature, as are good illustrations that reveal the plumage and bill size
distinctions. The separation of hyperrhynchus/paraensis would also be
consistent with the recognition of N. swainsoni as a separate
species (as treated in Rasmussen & Collar 2002, and as proposed in SACC
Proposal #124 that we follow). N. swainsoni
differs from the rest of the macrorhynchos complex to a similar degree
(both vocally and morphologically) as does hyperrhynchus/paraensis from
nominate, the main difference being that there is more published support for
the former split.
This split would result in two
species: a monotypic N. macrorhynchos; and a polytypic N.
hyperrhynchus (to include N. h. paraensis).
Recommendation: I
recommend a YES vote on splitting these two groups, in spite of the absence of
any real published analysis. These taxa were originally considered separate
species, and were subsequently lumped without published justification. I don't
think undoing this unjustified lump should be held to a higher standard, but,
in any case, a higher standard exists in the form of published qualitative
descriptions of vocal, plumage and size differences. Weak as the published justification
is, I believe that the distinctions behind it are sound and biologically
significant. If this passes, I'll put together a short proposal suggesting an
English name.
Literature Cited:
AMERICAN
ORNITHOLOGISTS' UNION. 1998. The A.O.U. Check-list of North American
Birds, Seventh Edition. American Ornithologists' Union. Washington D.C.
CLEMENTS,
J. F. 2000. Birds of the world: a check-list, Fifth Edition. Ibis
Publishing Company, Vista, California.
CORY, C. B.
1919. Catalogue of birds of the Americas. Publications of the Field Museum of
Natural History, Zool. Ser. 13(2):608 pp.
HILTY, S.
L. 2003. Birds of Venezuela. Princeton University Press, Princeton, New Jersey.
MEYER DE
SCHAUENSEE, R. 1966. the species of birds of South American 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.
PETERS, J.
L. 1948. Checklist of birds of the world, vol. 6. Museum of Comparative
Zoology, Cambridge, Massachusetts.
RASMUSSEN,
P. C. AND N. J. COLLAR. 2002. Family Bucconidae (Puffbirds). Pp. 102138 in:
del Hoyo, J., Elliott, A., & Sargatal, J., eds. (2002). Handbook of
the birds of the world, Vol. 7, Jacamars to Woodpeckers. Lynx Edicions,
Barcelona.
RIDGELY, R.
S., AND P. J. GREENFIELD. 2001. The birds of Ecuador. Vol. 2. Field Guide.
Cornell University Press, Ithaca, New York.
RIDGWAY, R.
1914. The birds of North and Middle America. Bull. U. S. Natl. Mus., no. 50,
pt. 6.
SIBLEY, C.
G., AND B. L. MONROE, JR. 1990. Distribution and taxonomy of birds of the
World. Yale University Press, New Haven, Connecticut.
STILES, F.
G. AND A. F. SKUTCH. 1989. A guide to the birds of Costa Rica. Cornell
University Press, Ithaca, New York.
Kevin
Zimmer, May 2004
_____________________________________________________________________________________
Comments from Silva:
"YES. The differences in plumage are very striking and as far as I know
these two species do not present any evidence for intergradation when their
ranges meet. Because they have been described as separate species and lumped
without any adequate taxonomic review, I fully agree with the proposal in
ranking these taxon as two distinct species."
Comments from Stiles:
"[NO] This case is like the preceding with one crucial difference: none of
the evidence has been published in detail. While I personally believe that
Kevin is right, I feel that if we are to maintain our insistence on published
evidence, available for independent evaluation (as we have on a number of
similar occasions), I must vote NO. (If Kevin wants to do a short note with
sonograms etc., might I recommend Ornitología Colombiana??)."
Comments from Robbins:
"YES, Kevin presents a very cogent argument for treating hyperrhynchus
as a species."
Comments from Jaramillo:
"YES. Instances such as this one
are really difficult for me. We are dealing with taxa that were originally
described as separate species, were lumped without published analysis, and
current information strongly suggests that this undocumented lump was not a
good decision. The full detailed analysis explaining why this split is a valid
way to deal with these taxa is not published, but the available data seems
pretty clear and I strongly suspect that Kevin is right in his analysis. The
stickler in me says, vote NO, yet the pragmatists says vote YES. There are so
many hundreds of these taxonomic issues in South America that need to be
tackled. Some may only need a few days’ work to pull together some data and
provide a note to a journal, but there are so few people willing to do this
type of taxonomic cleaning up that it seems like many of these questions will
not be resolved in many, many decades. I think I will forever be flipping back
and forth on how to deal with these types of records, and I commend those that
are much more clearly thinking and resolute in their stances. In this
particular case, I am taking these verbal descriptions of voice as data, and
they are published albeit in literature that was not peer reviewed. Even so
they are something on which to anchor this decision, the original lump does not
seem to be anchored on anything and that troubles me more than splitting with
no published analysis, but some data. I do think that publishing in a venue
such as Ornitología Colombiana is a superb way to get something on these
issues in print."
Comments from Nores: "NO. Aunque Zimmer parece tener razón, no veo que hayan
trabajos publicados que justifiquen la separación. Como este caso hay muchos otros en
la misma situación."
Comments from Pacheco: "YES. Em minha primeira experiência sonora com a
forma nominada de macrorhynchos ao norte do baixo Amazonas (Amapá),
eu julguei que minhas gravações pudessem representar ordii; na medida em
que, conhecia antes as vozes distintas de "macrorhynchos" paraensis
de Carajás (sul do Pará). É possível (como sugerido por Kevin) que macrorhynchos
seja - no escudo Guianense – o representante do grupo relictual ordii/swainsoni.
Manter hyperrhynchus e macrorhynchos reunidos, como formas alopátricas de
uma mesma espécie, é abonar uma decisão inexata, arbitrária e anacrônica
de Peters (1948), diante das informações agora disponíveis."
Comments from Remsen:
"YES. My usual vote in cases such as this is "no" due to
insufficient published information. However, the qualitative descriptions of
voices that have been published combined with the absence of any published rationale
for the original merger of a taxon ranked at species level by Ridgway and
Cory."