Moss-backed Tanager Bangsia edwardsi Scientific name definitions

The Moss-backed Tanager is typical chunky-bodied Bangsia tanager with a comparatively large-looking head, which is violet-blue, contrasting with the largely dull green body plumage, and the yellow center to the upper breast. It is a group-living bird, which is found just as frequently apart from other species as within mixed-species flocks. Another unusual behavior of the Moss-backed Tanager is the propensity for individuals to perch high on an exposed perch in a clearing or above the forest canopy. The species is distributed from west-central Colombia to northwest Ecuador, and ranges to elevations around 2100 m in wet and mossy cloud forests.

Both parts of the Latin binomial honor early ornithologists. Bangsia is named for Outram Bangs, a United States zoologist and collector; the specific epithet edwardsi honors Henri Milne Edwards, a French zoologist (Jobling 2010). This species is locally known by many common names including Bangsia Cariazul (Chaparro-Herrera et al. 2013), Bangsia Dorsimusgosa (Delgado Cerón 2017), and Tangara de Edwards (de Juana et al. 2012). In German it has been given the common name Edwardstangare (Strewe 2003).

This chunky hunk has a thick stubby bill, dark violet-blue on the sides of the head which is otherwise is black, and a dark moss-green back. The dark flight feathers are edged blue-green. Below the green is brighter and more yellowish. Most conspicuously, the upper breast has a central bright yellow spot.

Adult individuals have the sides of the face are dull to pale shining blue which are enclosed by a black front, crown, lores, ocular area, throat and center of nape (Ridgely and Tudor 1989, 2009; Hilty 2011). The back and upperparts including the upper tail coverts are moss green (Ridgely and Tudor 2009, Hilty 2011). The wings and tail are a dusky with the outer web dull dark green, the lesser and median wing coverts are dark green tinged dark blue (Hilty and Brown 1986, Hilty 2011). The secondaries are edged dusky bluish and the tertials are dusky (Hilty 2011). Centrally on the upper chest is a conspicuous golden yellow patch, they are otherwise mostly olive green below (Hilty and Brown 1987). Sometimes a poorly defined yellow median runs down the underparts from the chest to the belly (Hilty 2011). The sexes appear similar to humans, but they are dichromatic under an avian model of vision, with males reflecting brighter and more extensively in the UV spectrum (Burns and Shultz 2012). Immature individuals look very similar to adults though duller overall, especially above (Hilty 2011).

The Moss-backed Tanager is fairly unmistakable (Ridgely and Tudor 2009). The combination of having a blue face, a conspicuous yellow chest patch, and having a primarily green body is diagnostic (Ridgely and Tudor 1989, Ridgely and Greenfield 2001). It most closely resembles its sister species, the Gold-ringed Tanager (Bangsia aureocincta), in that both have conspicuous upper breast patches of bright yellow, greenish backs and greenish underparts, and wings tinged bluish. Further, they share a distinct "trilling alarm note" vocalization (Stiles 1998). However, Moss-backed Tanagers lacks the conspicuous bright yellow ring around the eye and ear coverts (Hilty and Brown 1986). Moss-backed Tanagers also resemble the Golden-chested Tanager (Bangsia rothschildi) which also has a prominent yellow patch on the upper breast. However, the Golden-chested Tanager is blackish in the face, back, and belly, and has bright yellow undertail coverts (Hilty and Brown 1986, Isler and Isler 1987). The Black-and-gold Tanager (Bangsia melanochlamys) and the Blue-and-Gold Tanager (Bangsia arcaei) have more extensive bright yellow below, with the later of these two species only known from Central America.

Tanagers that have been studied have either a Complex Basic Strategy or Complex Alternative Strategy (Ryder and Wolfe 2009). However, most tanagers only molt once a year, and this prebasic molt likely occurs after the breeding season (Isler and Isler 1987, Ryder and Wolfe 2009). Many species have been found to breed in subadult plumage (Isler and Isler 1987).

The upper mandible is light dusky (looking pale in the field) and the lower mandible is yellowish (Hilty and Brown 1986). The eyes are dark brown (Restall et al. 2006). The legs and feet are grey (Restall et al. 2006).

The length is about 15-16 cm (Hilty and Brown 1986, Isler and Isler 1987). Reported weights (n=7) had a mean of 37 g, with a min. of 34 mm and a max of 39.4 mm (Salaman 2001, Dunning 2008). A minimum weight of 33.5 is reported by Hilty (2011). Though the specific wing and tail measurements were not reported, the wing to tail ratio is 1.6 - 1.8 (Lowery and O'Neill 1964).

The Moss-backed Tanager is monotypic (Clements et al. 2018, Dickinson and Christidis 2014).

The Moss-backed Tanager, Bangsia edwardsi (Elliot, 1865) was described from an unspecified locality in Colombia (Storer 1970). All species of Bangsia originally were described as Buthraupis, but the smaller and shorter tailed species were recognized as distinct by Penard (1919), who proposed the genus Bangsia for this group. This classification remained controversial, and Storer (1970) merged Bangsia back into Buthraupis; this classification was accepted by some (e.g., Parker et al. 1996) but not all other authorities (e.g., Monroe et al. 1993). We now know via molecular phylogenetic analyses that Bangsia and Buthraupis in not sister genera (Sedano and Burns 2010, Burns et al. 2014). This hypotheses is corroborated by physical characteristics: Gold-ringed Tanager is more like other species of Bangsia in its smaller size, shorter tail, more uniform plumage, lower elevation preference, and generally less social behavior (Penard 1919, Hilty 2011, Burns et al. 2014). The Moss-backed Tanager is thought to have a discontinuous distribution along the Colombian Pacific Slope and perhaps this is reflected by the high intraspecific divergence of 1% for the mitochondrial locus cyt b (Sedano and Burns 2010).

The genus Bangsia consists of five or six species; four of which are found in the Northern Andes: Moss-backed Tanager (B. edwardsi), Gold-ringed Tanager (B. aureocincta), Golden-chested Tanager (B. rothschildi), and Black-and-gold Tanager (B. melanochlamys). The fifth species, Blue-and-gold Tanager (B. arcaei), is located in Costa Rica and Panama (Clements et al. 2018). The potential sixth species is the nondescript Yellow-green Chlorospingus (Chlorospingus flavovirens) which molecular phylogenetics has recovered within the Bangsia genus, as sister to Bangsia arcaei (Avendaño et al. 2016). However, this species name has not been officially transfered to Bangsia in the Clements or eBird checklists, and this treatment is badly needed (Clements et al. 2018, Remsen et al. 2018). Molecular phylogenetic analysis has consistently recovered a monophyletic Bangsia with strong support (Sedano and Burns 2010, Burns et al. 2014). Relationships within Bangsia also are strongly supported, with Moss-backed Tanager sister to Gold-ringed Tanager. These two species, though having very different plumage, are very closely related, with molecular phylogenetics recovering this recent divergence well-supported and subtended by a relatively long phylogenetic branch (Sedano 2013, Avendaño et al. 2016). It has been hypothesized that perhaps this is an example of a Pleistocene diversification event (Sedano and Burns 2010). The clade formed by these two species is sister to a clade comprised of the Golden-chested Tanager and Black-and-gold Tanager, with the Central American Blue-and-gold Tanager sister to the Yellow-green Chlorospingus, then to all other Bangsia (Burns et al. 2014). The clade containing the four South American species share the character of having heavier bills than the Blue-and-Gold Tanager (Penard 1919).

Bangsia is a member of a clade of tanagers largely restricted to the Andes, including the genera Wetmorethraupis (the sister genus to Bangsia), Pipraeidea, and Iridosornis, with the clade formed by these genera sister to the mountain tanager clade including Buthraupis, Anisognathus, Calochaetes, Chlorornis, Delothraupis, and Dubusia (Sedano and Burns 2010, Burns et al. 2014). That Bangsia is nested in a group of tanagers largely confined to the Andes Mountains suggests that these tanagers radiated in the Andes of northwestern South America (Sedano and Burns 2010). Like all tanagers, this species is a member of the family Thraupidae, with further genetic analyses showing that Gold-ringed Tanager belongs to the subfamily Thraupinae (Sedano and Burns 2010, Burns et al. 2014).

Fossils are not known for this species.

The Moss-backed Tanager is endemic and resident (nonmigratory) in the Western Andes subregion of the Northern Andes along the Pacific Slope in western Colombia and northwestern Ecuador (Parker et al. 1996, Chaparro-Herrera et al. 2013, Clements et al. 2018). They are recognized as an element of the Chocó Area of Endemism (Cracraft 1985). More specifically, the Pacific slope from around Valle, Colombia to Pichincha in the San Miguel de los Bancos area, Ecuador (Isler and Isler 1987, Ridgely and Greenfield 2001). The distribution is perhaps discontinuous, with gaps in its known range in the Cuaca Province despite containing habitat similar to the adacent Nariño and Valle de Cuaca provinces (Sedano and Posada 2014). It most often occurs along an elevational band between 600-2200 m along heavily forested Andean foothills (Haffer 1967, Isler and Isler 1987, Parker et al. 1996, Vogt 2007, Ridgely and Tudor 2009, Sedano and Posada 2014, Ocampo-Peñuela 2016). In Colombia they have been reported to occur as low as 400 m but are typically found above 900 m in Nariño and above 1200 m in Valle (Hilty and Brown 1986). In Ecuador they are primarily observed between 500 m and 1100 m, locally to as high as 1700 m in Carachi (Ridgely and Greenfield 2001). This species has an allopatric distribution with the congener Golden-chested Tanager (Bangsia rothschildi) via elevational tiering (Haffer 1967, Hilty and Brown 1986, Strewe 2003). Perhaps these two species competitively exclude one another, for differences in diet and foraging microhabitat were not detected (Posada and Stiles 2006). The elevational range of the Golden-chested Tanager and the Moss-backed Tanager possibly overlap, and annual rainfall may be driving these range limits (Haffer 1967). In Colombia this species is usually found above 900 m, and in Ecuador is usually found below 1100 m (Restall et al. 2006). Perhaps the Moss-backed Tanager more into lower elevations in Ecuador where it occurs south of the Golden-chested Tanager distribution (Haffer 1967). Late-year down-slope movements have been recorded for this species in Colombia (Hilty 1997).

The Moss-backed Tanager is endemic to the South American countries of Colombia and Ecuador.

The Moss-backed Tanager has been inferred to have lost 22.4% of its historical habitat, 3.7% of which has occurred in the last 10 years (Sedano and Posada 2014).

The Moss-backed Tanager occupies humid and dense epiphyte-laden forests at the Pacific slope premontane ecotone between the tropical lowland evergreen forest in the Andean foothills and montane evergreen forests (Haffer 1967, Isler and Isler 1987, Parker et al. 1996, Ridgely and Greenfield 2001, Strewe 2003, Vogt 2007, Ridgely and Tudor 2009, Clements et al. 2018). They are considered a montane element that extends into the Chocó Rainforest Center of Endemism (Cracraft 1985). They are known to occasionally occur at forest edges, second growth forests, and rarely trees in clearings (Isler and Isler 1987, Manne and Pimm 2001, Ridgely and Greenfield 2001, Vogt 2007, Ridgely and Tudor 2009). They typically occur in the middle or lower levels of the canopy to the understory (Hilty and Brown 1987, Restall et al. 2006).

Moss-backed Tanagers rely on both fruit and arthropods for food, eating fruits more often in the canopy and insects more often in the sub-canopy (Posada 2005, Posada and Stiles 2006). They have been reported eating the fruits of melastomes including Miconia majalis and Blakea podagrica (Hilty 1974). Also, they ate the fruits of epiphytes and parasitic plants (Isler and Isler 1987). They consume flying insects (Hilty 1974).

Typically they forage from the middle to upper levels of the forest canopy, but occasionally descend lower opportunistically (Hilty 1974, Isler and Isler 1987, Parker et al. 1996). Normally they forage alone or in pairs among thick mats of vegetation and epiphytes (Hilty 1974). Fruits are picked or pecked while perched (Isler and Isler 1987). Arthropods are gleaned from the foliage, flushed insects are flutter-pursued, and they will sometimes sally or lunge for flying insects (Hilty 1974, Isler and Isler 1987). A pair was observed opportunistically foraging on flying insects escaping an army ant (cf. Labidus praedator) swarm (Hilty 1974). The diet and foraging strategy of the Golden-chested Tanager (Bangsia rothschildi) is not statistically different than the observations made for the Moss-backed Tanager (Posada and Stiles 2006).

The Moss-backed Tanager is typically non-vocal (Ridgely and Greenfield 2001). The song is a staccato of alternating ascending and descending abrupt notes. The songs from Nariño have been described as a bubbly, rattling trill tr'e'e'E'E'e'e'r tr'e'e'E'E'e'e'r that can be delivered continuously without interruption for up to a minute (Hilty and Brown 1986). The song is primarily given soon after dawn from a prominent perch (Ridgely and Tudor 2009). Breeding birds may perch conspicuously above the canopy to deliver their song (Ridgely and Tudor 1989). The call note is a short, spitting high-pitched psheee (Isler and Isler 1987). Juveniles beg, and adults have been recorded giving both single- and double-noted territorial calls, as well as disturbance or agitation alarm calls (Jahn et al. 2002). They share a distinct "trilling alarm note" vocalization with the Gold-ringed Tanager which is their sister species (Stiles 1998). The vocalizations of the Moss-backed Tanager are raspier than the Blue-and-gold Tanager (Bangsia arcaei) and the Black-and-gold Tanager (Bangsia melanochlamys; Hilty and Brown 1986). Additional audio recordings of vocalizations of the Moss-backed Tanager can be heard at Macaulay Library and at xeno-canto.

They fly directly from tree to tree with a heavy buzzy flight (Isler and Isler 1987, Hilty 2011).

The chunky Moss-backed Tanager flies directly from tree to tree with a heavy, buzzy flight (Isler and Isler 1987). They often hop slowly along moss-laden branches, sometimes hopping with 180° turns (Restall et al. 2006). They will perch for long periods without moving, but generally perch in the open so are not difficult to see (Ridgely and Greenfield 2001). They have been observed frequently perched quietly on a open perch overlooking the forest (Hilty and Brown 1986).

There is no information on territoriality in this species that we are aware of.

There is no information on sexual behavior in the species that we are aware of.

They have been characterized alternatively as usually solitary, usually in pairs or small intraspecific groups, being sometimes found following mixed species flocks, to being found in such flocks about half the time (Isler and Isler 1987, Gregory 1997, Ridgely and Tudor 2009, Sedano and Posada 2014). The were observed opportunistically associating with the Uniform Antshrike (Thamnophilus unicolor) accompanying an army ant (cf. Labidus praedator) swarm (Hilty 1974).

Predation of Moss-backed Tanagers have not been reported to our knowledge.

The nest and eggs of the Moss-backed Tanager have been described from material collected from the wet foothill forests of Esmeraldas, Ecuador (Robbins and Glenn 1988). The nest is an open cup that was placed at the junction of two small moss-covered branches near the trunk of an understory tree; the nest was about 2 meters above the ground in a forest with a canopy height of about 20 meters. The bulk of the nest was comprised of fresh material, including the fronds from three fern species and moss. The inner lining consisted of a thin wiry vine. The diameter and depth of the interior cup was 65 mm and 30 mm. The eggs are subelliptical, 26.5 mm long and 18.2 mm wide, white and non-glossy, finely speckled brownish-red at the smaller end, becoming heavily blotched to a dense ring at the large end (Robbins and Glenn 1988). Begging juveniles were recorded in June 1997 from Playa de Oro, Ecuador (Jahn et al. 2002), and recent fledglings were recorded in January 1973 in Alto Yunda, Colombia (Hilty 1977).

Population trends for the Moss-backed Tanager are thought to be decreasing (Sedano and Posada 2014, BirdLife International 2018). They have been characterized as locally uncommon, locally common, to common (Negret 1994, Vogt 2007, Ridgely and Greenfield 2001, Ridgely and Tudor 2009). Parker (et al. 1996) considered them to be fairly common relative to other Neotropical birds. Though they are considered less numerous in the southern part of their range, they are one of the most common birds at El Placer and at Reserva Ecológica Cotacachi-Cayapas in Esmeraldas, Ecuador (Ridgely and Tudor 1989, Gregory 1997, Ridgely and Greenfield 2001). Assessments have inferred a distribution of 22,600 km², though when refined by available habitat perhaps as little as 3,556 km² is suitable for the species (Ocampo-Peñuela 2016). Their generation time has been estimated at 3.7 years (Sedano and Posada 2014). They are hosts for a louse species in the genus Myrsidea, with both of the two specimens examined having these parasites (Soto-Patiño et al. 2018). Competitive exclusion with the Golden-chested Tanager (Bangsia rothschildi) may preclude this species from occupying mesic forests lower in the foothills (Posada and Stiles 2006). No information is available on age at first breeding, survivorship, or other population regulating mechanisms.

Though the population trend is decreasing, they do not approach the range size, rate of decline, or population size thresholds for categorization as Vulnerable under the IUCN Red List and thus have been assigned to Least Concern (BirdLife International 2018). For example, the species range is estimated to be 81,300 km² whereas a range <20,000 km² is required to be cosidered Vulnerable. Parker et al. (1996) considered this species of "medium" conservation priority relative to other Neotropical birds. The species is covered in the Colombian Red List where they assign the category "Near Threatened" due to a small and fragmented distribution, with populations and suitable habitat continuing to decline (Sedano and Posada 2014).

The Moss-backed Tanager has lost an estimated 22.4% of its historical habitat, 3.7% of which has occurred in the last 10 years (Sedano and Posada 2014). Populations have been severely fragmented and are in decline (Sedano and Posada 2014). The habitat of this species has experienced extensive and ongoing deforestation, increased gold mining, as well as potential poisoning from extensive fumigation to eradicate illicit crops within its range (Sedano and Posada 2014). The species is known to use older second growth habitat and forest edges (Manne and Pimm 2001, Vogt 2007, Hilty 2011). Parker et al. (1996) considered Moss-backed Tanager to have a "medium" degree of sensitivity to human disturbance relative to other Neotropical birds.

As evidenced by the many Spanish common names that have been given to this species (see Introduction), it is a striking species that people notice. Because of its beauty and restricted distribution, this and most Bangsia species are used by ecotourist companies and tourism ministries as advertisement (e. g. Díaz and Lasso 2014). Thus, their conservation has direct economic value. This species is known from the following protected areas: Ecuador: La Reserva Amagusa (Delgado Cerón 2017); Reserva Ecológica Cotacachi-Cayapas IBA (Gregory 1997); Reserva Bellavista, Refugio Paz de las Aves, Milpe Bird Sanctuary, Reserva Río Manduriacu, Reserva Los Cedros, Reserva Geobotánica Palulahua (eBird 2018); Colombia: Reserva Natural (RN) El Pangán, RN Río Ñambí, RN La Planada (Orejuela and Cantillo 1990, Posada 2005, Sedano and Posada 2014); Parque Nacional Natural (PNN) Munchique (Negret 1994); PNN Farallones de Cali (Hilty 2011); Reserva La Nutria (eBird 2018).

Parker et al. (1996) considered the Moss-backed Tanager to have a low research priority relative to other Neotropical birds. Along with the Golden-chested Tanager (Bangsia rothschildi) these species may provide an empirical example of competitive exclusion via elevational tiering in birds. The know distribution of this species if highly disjunct, and the areas of suitable habitat between known populations should be surveyed. Equally, these apparently disjunct populations should be evaluated for the amount of divergence that has occurred between them and the amount of gene flow that is occurring between them.