Bearded Mountaineer is a very distinctive species of the southern Andes. Bronze-tailed and Gray-bellied comets are much drabber; Gray-bellied Comet also is inexplicably rare and very local.
BIRDS BEARDED MOUNTAINEER Oreonympha nobilis * 15.5–16.5 cm (6–61⁄2 in); bill 2.4 cm (1 in) Uncommon in dry montane scrub in intermontane valleys of south-central Andes, 2700–3900 m.
Often seen at tree tobacco, Nicotiana, an exotic plant found along road edges. Large size, long forked black-and-white tail, and white underparts render it unmistakable. Male has narrow green and purple gorget. Crown bordered with whitish line, speckled with green, in albolimbata (Huancavelica), or with deep glittering blue (more widespread nobilis). VOICE Call a descending, squeaky series followed by a rich chatter: “swee swee chew-chew-chew.” Also a dry “dzzrt.” ENDEMIC AMAZON BIRDS OF PERU.
The Bearded Mountaineer (Oreonympha nobilis) is a restricted-range species found in the Peruvian High Andes, with two currently recognized subspecies: O. n. nobilis from the Apurimac and Urubamba valleys near Cuzco (Fjeldså 1999, Schulenberg et al. 2010), and O. n. albolimbata from Huancavelica and the south basin of the Apurimac river (Fjeldså 1999). It has been considered uncommon to locally common (Fjeldså 1999, Schulenberg et al. 2010, BirdLife International 2011), and inhabits semi-open and dry mountain scrub with Cactaceae, often in proximity to settlements with Nicotiana bushes and Eucalyptus trees, as well as forests with Escallonia/ Polylepis with dense thorny scrub in rocky terrain between 2500 and 3900 m a.s.l. (Fjeldså 1999, Schulenberg et al. 2010, A. Weller pers. com.). There is no information on the breeding biology of this species and no nest has previously been described, even though Morrison (1939) and Fjeldså (1999) have suggested it might nest in caves or gorges in stream ravines.
METHODS – BIRD WATCHING PERU:
Observations of the Bearded Mountaineer (O. n. nobilis) were made at the entrance to the Tipon Archeological Park (13°34’S, 71°47’W, 3560 m a.s.l.), Oropesa district, Quispicanchis province, Cuzco, Peru. All observations were done 12 November 2011 during a short afternoon visit. The area was covered with scrub vegetation with scattered shrubs and some grass, with agricultural lands surrounding the archeological site and some Eucalyptus trees along the road.
RESULTS AND DISCUSSION – BIRD WATCHING PERU:
We observed a female Bearded Mountaineer hovering at a Dunalia espinosa (Solanaceae) bush (c. 1.5 m tall) with purple flowers, both alone and with Black-throated Flowerpiercer (Diglossa brunneiventris) on the same bush, without any behavioral interaction between them. The female Bearded Mountaineer visited several flowers at a time before flying to either a nearby cliff or to the underside of the thatched roof of a cabin nearby, where we found her nest. The individual stayed at the nest for at least 5 min at a time, and left it repeatedly for short periods (5–6 min). Each time, she visited the nearby Dunalia espinosa flowers, then flew towards other plants on a nearby cliff (10–15 m away from the nest) and finally returned to her nest in a straight line.
We discovered the nest 2.25 m from the ground, attached to overhanging straws, on the underside of the cabin’s thatched roof at the entrance of the park. The nest was a compact open cup/lateral type (Simon & Pacheco 2005) almost suspended; made mainly of fern ramenta, rootlets, fibers, and moss; and externally with green moss, a few lichens and only traces of cobwebs (Fig. 1A). Internally, the eggcup contained mainly green moss and some loose feathers (Fig. 1B). The nest was a little asymmetrical, longer on the left side, and with some loose hanging “tail” extensions of nesting material. The external measurements of the nest were 67 mm wide, 55 mm long on the right side, and 70 mm long on the left (94 mm, including the hanging material). The inner diameter was 41 x 42 mm, with an estimated depth of c. 20 mm. The nest contained two immaculate white eggs, as typical for all hummingbirds (exceptionally three; e.g., reported for Chalcostigma herrani by Borrero 1952), of c. 15 x 10 mm (Fig. 1B).
The nest was similar to that of the related Bearded Helmetcrest (Oxypogon guerinii) and Rainbow-bearded Thornbill Chalcostigma herrani, being suspended and externally constructed with moss and roots, but not having the soft wooly lining plant material found in the inside cup of Oxypogon nests (Moore 1934, Ruschi 1961, Snow 1983), which was replaced instead by some scattered feathers. The nest also had thick (18–20 mm) walls similar to the nests of Oxypogon and other high elevation hummingbirds, probably for insulation purposes, since cold winds are common in the afternoons and the temperature drops at night (Ruschi 1961, Carpenter 1976, Snow 1983).
The nest was placed in a protected overhanging, and thus sheltered from rain and direct sunlight, and somewhat from wind, not far away from the running water of Tipon’s canal system and waterfalls. This is similar to the nest locations (in rocky walls, cliffs, or caves) reported for other Andean trochilids (Moore 1934, Ruschi 1961, Snow 1983, Züchner 1998). In general, nest architecture and placement support the systematic position of the monotypic genus Oreonympha to be the closest relative of Chalcostigma and Oxypogon within the Andean clade of the coquettes as indicated by recent phylogenetic studies (McGuire et al. 2007, 2009).
Most likely, the Bearded Mountaineer breeds during the rainy season as has been proposed for the Andean Hillstar (Oreotrochilus estella) and other hummingbird species also found at high altitudes in this area (Carpenter 1976, del Hoyo et al. 1999). November corresponds to the onset of the rainy season around Cuzco, which continues until May with an annual average of c. 732 mm (Ministerio de Agricultura 2010).Cusco, eggs, nest, Oreonympha nobilis, Peru, restricted range, SudAmerica, Trochilidae