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Black-headed Trogon Trogon melanocephalus

  • Order: Trogoniformes
  • Family: Trogonidae
  • Polytypic: 2 subspecies
  • Authors: C. Riehl
Sections

Breeding

Nest site selection and pair formation

No information available.

Phenology

In Guatemalan lowlands, Skutch (1948) recorded one pair that constructed a nest from April 8 – 14 and laid eggs from April 20 – 25; one egg hatched on May 14 but was depredated by May 29. The same pair then re-nested and had laid a new clutch by July 9. A second pair in the same location had 3 eggs on May 6. In deciduous forest in Costa Rica, several pairs were observed to initiate nests in June and July, with two pairs re-nesting into late August (Riehl 2005). Stiles and Skutch (1989) give the breeding season as March through July in Costa Rica.

Nest

All nests that have been described were located in arboreal termitaria inhabited by Nasutitermes termites (Skutch 1948, N = 3 nests in Guatemala; Riehl 2005, N = 14 nests in Costa Rica). Nesting termitaria may be located in trees, fence posts, or other low supports, frequently along forest edges, roads, streambeds, or on exposed fence rows (Skutch 1948, Stiles and Skutch 1989, Riehl 2005). Of the 3 nests in Guatemala, 2 were ≤ 1m above the ground and one was 1.5 m above the ground. Of the 14 nests in Costa Rica, nest height ranged from 2.6 – 5 m (mean = 4 ± 1.1 m; Table 1). At all 3 nests described by Skutch (1948) and 11 of the 14 nests described by Riehl (2005), the entrance hole was located at the bottom of the termitarium and led to a sharply upward-curving tunnel that ended in an unlined nesting chamber in the heart of the termitarium. Nesting adults must therefore enter the nest from below, sometimes by perching below the nest (or on the ground) and flying upwards (Skutch 1948). 3 of 14 nests in Costa Rica had horizontal entrance tunnels leading directly to the nest chamber and may have been secondary cavities originally excavated by Orange-chinned Parakeets Brotogeris jugularis (Riehl 2005). The termitaria housing two nests measured by Skutch (1948) were 24 in (57.6 cm) and 33 in (79.2 cm) in height by 16 in (38.4 cm) and 18 in (43.2 cm) in diameter, respectively. One nesting chamber was 7.5 in (18 cm) in height and 5.5 in (13.2 cm) in diameter with a tunnel 6 in (14.4 cm) in length and 2.5 in (6 cm) in diameter. The inside of the nesting chamber was not lined.

Skutch (1948) described the construction of one nest cavity in detail. Both male and female took turns excavating the cavity, although the male typically worked for longer periods than the female (each shift lasting from 1 to 30 minutes). Male excavated cavity only when female was present. Most excavation took place from late morning (10:30 – 11:00 a.m.) through late afternoon (4:00 – 5:00 p.m.) over a period of at least 7 days. Both adults apparently excavated by biting and twisting thin layers of the termitarium, rather than by hammering. Once the trogons had reached the interior of the termitarium, excavated pieces were pushed out of the nest chamber through the entrance tunnel.

Eggs and clutch size

White, laid at two-day intervals. Measurements of 2 unhatched eggs from the same nest were 29.8 x 22.6 and 31.0 x 23.0 mm (Skutch 1948). All 3 nests in Guatemala contained 3 eggs, although at 1 nest only 1 hatched. In Costa Rica, 3 nests contained 2 nestlings and 1 nest contained 3 nestlings, but the number of eggs in the clutch was not determined (Riehl 2005). Estimated egg weight 8.1 g, 28.6 x 22.5 mm (Schönwetter 1966, cited in Johnsgard 2000). Pairs will re-nest in a different location if the first clutch is depredated.

Incubation

Incubation patterns at 4 nests observed by Riehl (2005) identical to that described for 1 nest by Skutch (1948). Each adult incubates for one continuous period per day: male incubates from morning (6:30 – 7:30 a.m.) to late afternoon (4:00 – 5:00 p.m.), then female incubates from late afternoon until the next morning. Eggs were left uncovered for a maximum of 45 min. In Costa Rica, incubating adults rarely left the nest except when disturbed by noise from people or nearby groups of white-faced capuchins (Cebus capuchinus) or golden-mantled howler monkeys (Alouatta palliata). Incubating adults also left the nest to chase Orange-chinned Parakeets away from the nest territory (Riehl 2005). Incubation period not precisely determined; apparently between 17 and 19 days (Riehl 2005, Skutch 1948).

Nestlings and parental care

Nestling development described by Skutch (1948). Newly hatched young are altricial, naked and with eyes closed. At 7 days eyes are still closed, but pin feathers have begun to emerge. Eyes open by 11 days. Pin feathers lengthen but do not emerge from keratinous shafts until 12 – 14 days, when they do so rapidly. Nestlings at 15 – 17 days are fully feathered, resemble miniature adults, and are capable of flight. Fledge at 16 – 17 days. Fledglings have extensive narrow white barring on the upper wing coverts, but less or none on the mantle and flight feathers. Extent of post-fledging parental care is not known.

Adults brood nestlings for at least the first few days after hatching (Riehl 2005). Male and female typically alternate food deliveries to the nestlings. Food delivery to nest is extremely infrequent when the nestlings are young, averaging ≤ 1 delivery per parent per hour (Skutch 1948, Riehl 2005). Frequency of food delivery increases to 3 – 5 times per parent per hour as nestlings get older, but can remain low at some nests (Riehl 2005). Infrequent food delivery may be an anti-predator strategy made possible by the large size of prey items brought to nestlings.

Recommended Citation

Riehl, C. (2012). Black-headed Trogon (Trogon melanocephalus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.blhtro1.01