Guatemalan Pygmy-Owl Glaucidium cobanense is a good species.

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In Middle America, the traditional view of
highland pygmy owls has been that birds from
Mexico south to Honduras were part of the
‘Northern Pygmy Owl’ Glaucidium gnoma
complex, whilst those in Costa Rica and Panama
were part of the Andean Pygmy Owl G. jardinii
complex1. Mexican populations, however, probably
comprise at least three species3, and recently the
southern Central American populations have been
treated as a distinct species, Costa Rican Pygmy
Owl G. costaricanum, which has phylogenetic
affinities with the mountain-inhabiting pygmy owls
of northern Middle America and not with Andean
Pygmy Owl of South America6. On the basis of its
plumage and biogeography, G. [gnoma] cobanense
from the northern Central American highlands
(Figs. 1–3), described by Sharpe7 in 1875, seemed
likely to prove specifically distinct from pygmy
owls in the mountains north-west of the Isthmus
of Tehuantepec, and the name Guatemalan Pygmy
Owl was provisionally suggested3. is owl was
treated as a full species, Guatemalan Pygmy Owl
G. cobanense, in the Handbook of the birds of the
world4. Now, a recent paper2 has compared the
voice of cobanense from Guatemala and Mexico
with nominate gnoma from Mexico, providing
additional support for species status.
Vocalisations of Middle
American highland pygmy owls
We here describe the voice of cobanense (Figs.
4–6) and compare it briefly to its closest montane
relatives, Mountain Pygmy Owl G. gnoma to the
north-west (here considered a species distinct
from the vocally very different Northern Pygmy
Owl G. californicum of the USA) and Costa Rican
Pygmy Owl to the south-east. See Eisermann &
Howell2 for details of recordings, some of which
can be heard online at the Macauley Library,
Cornell Lab of Ornithology (www.macauleylibrary.
org) and at xeno-canto (XC; www.xeno-canto.org).
Sonograms here were produced using RavenLite
software, with a ‘spectrogram sharpness’ value of
404.
e hooting of cobanense is notably faster
paced than that of gnoma (typically 30–35 notes /
10 seconds vs. 16–19 notes / 10 seconds in gnoma)
and can be given in repeated bursts of 3–4 hoots
(Fig. 4) and in prolonged series, often with a paired
rhythm (Fig. 6b). As in other pygmy owls, bursts
of hooting can be preceded by quavering whistles.
Another vocalisation that may draw attention
is the very rapid-paced whiwhiwhi … given by
females when establishing a nest site (Fig. 5); the
pattern of this call may suggest a high-pitched
Northern Flicker Colaptes auratus or a small
falcon.
A comparison of the song of cobanense with
that of Costa Rican Pygmy Owl (Fig. 6b–c) reveals
that both are decidedly fast-paced relative to
gnoma (Fig. 6a), but in these examples cobanense
is even faster paced than costaricanum (30–35
notes / 10 seconds vs. 26–28 notes / 10 seconds)
and has distinctly paired hoots; consequently, it
sounds quite different. Fig. 3b of Robbins & Stiles6
shows that costaricanum can produce around 32
notes / 10 seconds in paired series, although with a
subtly but distinctly different rhythm to cobanense
(costaricanum has notes within pairs more widely
separated, but with shorter pauses between pairs
than cobanense). Moreover, costaricanum averages
74 Neotropical Birding 9
Guatemalan Pygmy Owl
Glaucidium
cobanense
is a good species
Steve N. G. Howell and Knut Eisermann
New World pygmy owls have ridden a long, tumultuous and undoubtedly
far from nished taxonomic journey, with numerous splits and new
species making their way into the literature in the last 20 years. One
enigmatic montane taxon is Glaucidium [gnoma] cobanense, which
occurs in highland forests from northern Chiapas state, Mexico, through
Guatemala to central Honduras. Its voice remained unknown into
the 1990s, and its taxonomic status thus remained unresolved.
>> PHOTOSPOT GUATEMALAN PYGMY OWL

75Neotropical Birding 9
Figure 1. Brown-morph Guatemalan Pygmy Owl Glaucidium cobanense in typical bromeliad habitat, Chanal Road,
Chiapas, Mexico, 3 March 2007 (the bird in recording Fig. 6). (Steve N. G. Howell)
Figure 2. Rufous-morph Guatemalan Pygmy Owl Glaucidium cobanense, Chelemhá Reserve, Alta Verapaz, Guatemala,
27 May 2008 (Knut Eisermann)
Figure 3. Brown-morph male Guatemalan Pygmy Owl Glaucidium cobanense at nest entrance, Chelemhá Reserve,
Alta Verapaz, Guatemala, 13 March 2010 (Claudia Avendaño)

76 Neotropical Birding 9
>> PHOTOSPOT GUATEMALAN PYGMY OWL
longer winged but shorter tailed than cobanense6,
which does not differ appreciably in size from
gnoma5. Such differences in voice and morphology
are comparable to those between other species of
pygmy owls, and the most realistic approach is to
consider cobanense a distinct species, Guatemalan
Pygmy Owl.
ACKNOWLEDGEMENTS
SNGH thanks Will Russell and WINGS for supporting
his travels in Mexico, Chris Wood and Rich Hoyer
for company in the field, Nathan Pieplow for help
with digitising recordings, and Andrew Spencer for
permission to use his recording of Costa Rican Pygmy
Owl. KE thanks UPROBON for hospitality and research
permission in the Chelemhá Reserve, and Claudia
Avendaño for providing a photograph.
REFERENCES
1. American Ornithologists’ Union (1998) Check-list of
North American birds. Seventh edn. Washington DC:
American Ornithologists’ Union.
2. Eisermann, K. & Howell, S. N. G. (in press)
Vocalizations of the Guatemalan Pygmy-Owl
(Glaucidium cobanense). J. Raptor Res.
3. Howell, S. N. G. & Webb, S. (1995) A guide to the
birds of Mexico and northern Central America. New
York: Oxford University Press.
4. Marks, J. S., Cannings, R. J. & Mikkola, H. (1999)
Family Strigidae (typical owls). In: del Hoyo, J.,
Elliott, A. & Sargatal, J. (eds.) Handbook of the birds
of the world, 5. Barcelona: Lynx Edicions.
5. Ridgway, R. (1914) e birds of North and Middle
America. Bull. US Natl. Mus. 50(6).
6. Robbins, M. B. & Stiles, F. G. (1999) A new species of
pygmy-owl (Strigidae: Glaucidium) from the Pacific
slope of the northern Andes. Auk 116: 305–315.
7. Sharpe, R. B. (1875) Contributions to a history of the
Accipitres. Notes on birds of prey in the museum at
the Jardin des Plantes and in the collection of Mons.
A. Bouvier. Ibis (3)5: 253–261.
STEVE N. G. HOWELL
PO Box 423, Bolinas, California 94924, USA.
KNUT EISERMANN
PROEVAL RAXMU Bird Monitoring Program, Cobán, Alta
Verapaz, Guatemala. E-mail: knut.eisermann@proeval-
raxmu.org
Left, top to bottom:
Figure 4. Spontaneous hoots in repeated short bursts
(note the rapid pacing within bursts) by Guatemalan
Pygmy Owl Glaucidium cobanense, Chanal Road,
Chiapas, Mexico, 13 March 2010 (Steve N. G. Howell)
Figure 5. Nest site vocalisation of female Guatemalan
Pygmy Owl Glaucidium cobanense, Chelemhá Reserve,
Alta Verapaz, Guatemala, 12 March 2010 (Knut
Eisermann)
Figure 6. Comparison of typical prolonged song of:
(a) Mountain Pygmy Owl Glaucidium gnoma, Oaxaca
state, Mexico, 19 March 2010 (S. N. G. Howell); (b)
Guatemalan Pygmy Owl G. cobanense, Chiapas state,
Mexico, 3 March 2007 (S. N. G. Howell); and (c) Costa
Rican Pygmy Owl G. costaricanum, Cartago province,
Costa Rica, 9 February 20011 (A. Spencer; XC72943).
Note the relatively slow pace of Mountain and quick
pace of Guatemalan. All three taxa often give notes in a
paired rhythm, but gnoma and costaricanum (at least)
can also give notes with fairly steady pacing.
(a)
(b)
(c)