Proposal (32) to South
American Classification Committee
Recognize Glaucidium mooreorum
Effect on South American CL: This proposal would add a newly
described species to the list
Background: Silva et al. (Ararajuba 10:123-130,
2002) presented evidence for recognizing a new pygmy-owl (Glaucidium
mooreorum) that is restricted to the Pernambuco region of the northern
Atlantic Forest of Brazil.
Although the evidence presented consisted of only two specimens
and a single sound recording, I believe they have convincingly established,
based on the very distinct song, that the Pernambuco Pygmy-owl is indeed
different from the morphologically very similar Amazonian Pygmy-owl (G.
hardyi) and Least Pygmy-Owl (G. minutissimum).
Plumage color and pattern is extremely similar among the presumed
Least Pygmy-Owl (G. minutissimum) species complex (sensu Howell and
Robbins 1995). Because of this extreme interspecific similarity coupled with
variability in plumage within each taxon (varying in brown and dull red
pigmentation and wear), I don't put any weight in the described color
differences that they present. Because there were only two specimens available
(no surprise given how difficult these subcanopy-dwelling owls are to obtain)
the relevance of the tail/ring ratio in separating these taxa is hard to
determine, especially given that one could argue that the two Pernambuco
specimen ratios fall within the range of minutissimum.
However, the primary vocalization that they present is very
distinct from that of minutissimum and hardyi. They
accurately describe this in paragraph 2, left hand column of page 127. Although
this is based on only a single recording (under natural conditions), my
experience with this complex suggests that there is little intraspecific
variation in natural song. Thus, I suspect that the vocal material that they
present is an accurate representation of this taxon. Because this is truly the
key (until we have genetic data) for separating these cryptically plumaged
owls, I believe, despite the very limited material, that the authors have
demonstrated that mooreorum deserves species rank.
Mark Robbins, June 2003
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Comments
from Zimmer:
"YES to add Glaucidium mooreorum as a new species to the list. I
would like to see a bigger sample size here, but I agree with Mark that there
doesn't seem to be much individual variation in this group (other than perhaps
slight variation in number of notes, e.g. 2 versus 3 or 4, within an
individual), so that the one tape recording is likely to reflect a very real
distinction. It also fits a biogeographical pattern. I'm not very impressed
with slight morphological distinctions (particularly color saturation) in this
genus -- I think voice is the key."
Comments
from Silva:
"YES. Voice is different as well as plumage coloration. Based on the
specimens that I examined of minutissimum and hardyi I
did not see a so large intraspecific variation in plumage color that seems to
be common in other species of the genus."
Comments
from Jaramillo: "YES I am a bit concerned regarding the small sample
sizes looked at, both skins and vocalizations. But I know a lot less than Mark
about variation in natural songs, thus the fact that he is comfortable with the
small number of voice samples is enough to make me comfortable with it."
Comments
from Nores:
"YES. Si estoy de acuerdo, aunque uno esperaría una
mayor cantidad de ejemplares y de registros vocales para dar una opinión
definitiva."