Azure-rumped Tanager Tangara cabanisi

  • Order: Passeriformes
  • Family: Thraupidae
  • Monotypic
  • Authors: Knut Eisermann


Nesting season: In Chiapas, nesting activity was observed from April-June, based on observations in all months except January, July, and August (Long and Heath 1994). Based in more extensive observations in all months at Atitlán volcano, nesting was recorded in all months from April-September (Eisermann et al. 2011b). Nesting is synchronized with the wet season (Long and Heath 1994, Eisermann et al. 2011b). Considering the long nesting season, possibly more than one brood is reared per season (Eisermann et al. 2011b), similar to congeners, e.g. Golden-hooded (Tangara larvata), Bay-headed (T. gyrola), and Silver-throated tanagers (T. icterocephala) (Skutch 1954, 1981).

Nesting habitat: A total of 42 nests of Azure-rumped Tanager have been reported (10 from Chiapas and 32 from Guatemala). These were placed in 23 different tree species (Long and Heath 1994, Gómez de Silva 1997, Eisermann et al. 2011b). In Guatemala, the elevation of nesting sites ranged 860-1850 m (mean ± SD: 1459 ± 210 m; n=32 nests). Tanagers were recorded nesting successfully in primary broadleaf forest, but also in coffee plantations with a greatly reduced or absent upper canopy of native broadleaf trees (Eisermann et al. 2011b). At Atitlán volcano, nest density was in forest 2 nests / 10 ha, in non-intensive shade coffee plantation 5.3 nests / 10 ha, and in intensive coffee plantation 0.8 nests / 10 ha (Eisermann et al. 2011b). Because nest detectability is likely much lower in the taller and denser forest than in non-intensive coffee plantation, a preference of non-intensive coffee plantation over forest can not be concluded. Noteworthy, however, is the greater nest density in non-intensive coffee plantation compared to intensive coffee plantation (Eisermann et al. 2011b).

Nest: Nests of Azure-rumped Tanagers are open-cup shaped and made of moss, lichen, rootlets of small epiphytic ferns, and soft cotton-like material (Long and Heath 1994, Eisermann et al. 2011b). Most nests are placed in the bifurcation near the end of branches, some supported by epiphytic ferns and orchids (Long and Heath 1994, Eisermann et al. 2011b). Nests are located in the upper vegetation strata. Of 40 nests with data, mean (± SD) nest height was 20.5 ± 11.2 m (n=40 nests), and mean (± SD) relative nest height in the vegetation was 76.6% ± 16.9 (range 44%-100%) (based on data in Long and Heath 1994, Gómez de Silva 1997, Eisermann et al. 2011b). One nest has been observed from the first day of building, which took 6 days (Eisermann et al. 2011b).

Eggs and clutch size: The eggs of Azure-rumped Tanager are “whitish, with a very pale pink wash and heavy red-brown speckling” (Gómez de Silva 1997). Measurements on egg size are not available. The greatest number of nestlings observed from a distance is 2 (Long and Heath 1994, Eisermann et al. 2011b), indicating that the usual clutch size seems to be 2.

Parental care: Incubation takes 14-15 days (Long and Heath 1994, Gómez de Silva 1997, Eisermann et al. 2011b). Incubation constancy calculated using the Skutch (1962) method was 67%-82% (Long and Heath 1994, Gómez de Silva 1997, Eisermann et al. 2011b). Brooding takes 15-17 days (Long and Heath 1994, Eisermann et al. 2011b). Adults feed the young in the nest 8-11 times / hour (Long and Heath 1994, Eisermann et al. 2011b).

Nest success: Using the Mayfield (1961, 1975) method for calculating nest survival from onset of incubation to the fledging of the first young, nest success of 18 nests at Atitlán volcano was 16% (95% confidence interval: 5-45%) (Eisermann et al. 2011b). Long and Heath (1994) supposed that young fledged from 29-43% of the nests (2-3 of 7 nests) in Chiapas. Applying an uncorrected calculation similar to Long and Heath (1994) to the data from Atitlán volcano, 4 of 18 (22%) encountered nests at Atitlán volcano were successful, 4 (22%) had an unknown fate, and 12 (66%) failed. Consequently, maximum number of successful nests was 44% (Eisermann et al. 2011b).

Cooperative breeding: Helpers were observed at several nests of Azure-rumped Tanager. While at two nests in Chiapas helpers were observed until the end of the incubation period (Long and Heath 1994), on a nest on Atitlán volcano a helper was observed from the first day of nest building throughout the nesting season (Eisermann et al. 2011b). A nest can be attended by one to several helpers (Long and Heath 1994, Eisermann et al. 2011b). Not all nests are attended by helpers; at Atitlán volcano, helpers were recorded at two of eight nests where feeding adults were observed on several dates for several hours (Eisermann et al. 2011b).

Recommended Citation

Eisermann, K. (2011). Azure-rumped Tanager (Tangara cabanisi), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.