Proposal
(11) to South American Classification Committee
Treat Otus
atricapillus, Otus hoyi, and Otus sanctaecatarinae as a
single species, O. atricapillus
RE atricapillus/hoyi/sanctaecatarinae.
I'd be interested in hearing what others think of this proposed split. Atricapillus
and hoyi sound very similar, but sanctaecatarinae sounds
quite distinct (listen to Hardy et al.). I wouldn't hesitate adopting Marshall and
Behrstock's suggestion of treating atricapillus
and hoyi as conspecific (in the liner notes of Hardy et al.), but König
et al.'s molecular data (page 46) has atricapillus sister to usta
and equally surprising, hoyi sister to petersoni and widely separated
from both atricapillus and sanctaecatarinae. The problem with
their data set is that they lack many taxa and the bootstrap values are quite
low for several of the nodes. Nonetheless, I believe the data are suggestive
enough to treat atricapillus, hoyi, and sanctaecatarinae all
as species.
Mark B.
Robbins, December 2001
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Comments from Schulenberg: "NO.
What I mean is that I am voting to continue to recognize all three taxa as
species, which I *think* is the status quo. As arranged on Van's proposal
tracking web page, the title of the proposal ("Lump Otus atricapillus,
Otus hoyi, and Otus sanctaecatarinae into a single species, O.
atricapillus") seems at odds with what Mark is suggesting ("I
believe the data are suggestive enough to treat atricapillus, hoyi,
and sanctaecatarinae all as species"). What I wish to endorse is
Mark's suggestion to treat atricapillus, hoyi and sanctaecatarinae
all as species. I am not convinced that
this is correct (recognizing all three as species). However, I am reluctant to
endorse any changes based on listening to a handful of recordings, or after
looking at a handful or fewer of sonograms.
I don't think that we are going to get anywhere in our understanding of
the Otus until someone gets serious about this and does a true
(quantitative, reasonably exhaustive) analysis of vocalizations. This approach
is all the more important when songs are similar, as seems to be the case here
(*how* similar is "similar"?, when is "similar" the same as
"identical"?, etc.). (I have
recordings of what I took at the time to be hoyi (Chuquisaca, Bolivia)
and of (what I think is) atricapillus from Espírito Santo, Brazil:
available for study to anyone who wants them.)
Clearly a genetic perspective on this would help as well. That said, I
am not very impressed with the work by Wink and Heidrich as presented in König
et al. It is not clear whether some samples are blood only or are tied to
museum specimens (a bit more detail, but not much, is presented in an earlier
paper on Otus molecular systematics by Heidrich et al., 1995, Z. Naturforsch. 50c: 294-302), and if there are specimens,
where these are deposited. Therefore, confirming any of their identifications
will be difficult if not impossible, which does not seem like a good place to
start. So although their genetic data so far support the recognition of these
three taxa as separate species (as Mark pointed out), I don't find this genetic
evidence particularly compelling either. In other words, still waiting for
someone to do it right. Just as an
example, Wink and Heidrich (in König et al.) have three samples of Otus "usta"
from "South America". I assume that these are the same three samples
of Otus "usta" referred to by Heidrich et al.
1995., where we learn that all three samples are from the LSUMZ (although
they don't specify LSUMZ numbers for these samples), and that the these come
from La Paz (their sample 1), the Rio Napo region (2) and Pando (3). Their
sample 2 of usta, therefore, is from a region where some authors (Chapman, HBW)
tell us watsonii would be expected. Heidrich et al. do not tell us how
they identified their sample 2 as usta:
by examining study skins (and if so, by what characters?)? by the vocal type prevalent
at the site where the sample came from? or simply because its genetic profile
matched that of birds from southwestern Amazonia (presumed
"certified" usta), and so therefore it has to be? THEY MAY BE
CORRECT, but the lack of attention paid to documenting the sources and
identifications of their samples greatly undermines my confidence in anything
else that they have to say. "
Comments from Nores: "NO. El Handbook dice de hoyi
"vocally distinct, and treatment as separated species supported by DNA
evidence", y de sanctaecatarinae "Formerly considered
conspecific with O. atricapillus, but vocally and morphologically
distinct, and treatment as separate species further supported by DNA evidence."
Además, sanctaecatarinae y atricapillus
tienen una distribución muy similar. Los ojos oscuros de atricapillus parece
ser una característica importante de la especie que las separa de hoyi y
sanctaecatarinae, y también de guatemalae.
From Alvaro Jaramillo: "No.
In another words, do not lump these three taxa together. There are several reservations
I have regarding a lump. One of which is that I recall that both sanctaecatarinae and atricapillus are
recorded from Iguazu National Park in Argentina (and presumably on the Brazil
side too). If the two are sympatric, well it needs to be addressed before a
lump. I do not know the validity of reports, if specimens are involved or any
details but do recall that both are apparently there. Hopefully I am not wrong
on this. I think there has been some confusion in the identification of
specimens and recordings of atricapillus and sanctaecatarinae,
which also needs to be resolved before we tackle a lump. Recordings of sanctaecatarinae I
have heard sound quite unlike atricapillus, being much harsher,
guttural, in tone. Having said that atricapillus does indeed sound
like hoyi, if a lump was to be made I feel better about these two
taxa being together and leaving sanctaecatarinae separate. One topic
that does bother me is if one can conclude anything if songs of two or more
taxa of owl are similar when they are allopatric. I don't know that this tells
us much, if anything about what to do in terms of lumping or retaining taxa as
separate species. Presumably if two populations of owl separate, in many
situations time alone will cause a divergence in song type, particularly if the
two populations end up in radically different habitats. However, there may be
strong mate choice or other factors that may keep the song from diverging after
separation, even after a great deal of time has elapsed and speciation has
occurred. There may also be a limited palette of sounds that New World Otus can
make, so some song types may emerge independently even in non-sister taxa. I
think this is clearly what goes on in oriole plumage patterns (based on work of
Omland and Lanyon's work) and presumably could happen in groups of birds where
song has a high genetic component. The similarly recurring patterns in Scytalopus tapaculo
vocalizations may be a similar situation, although I don't know if similar
songs are always shared by closely related taxa in that case. "