Blue-tailed Emerald Chlorostilbon mellisugus Scientific name definitions

Ranging across much of northern South America, including western Brazil and south into Bolivia, the Blue-tailed Emerald is found in fairly open and semi-dry habitats in the tropical and subtropical zones, (up to 2200m). It is widespread and common in Colombia and Venezuela, fairly common in the Guianas, and uncommon to local in Ecuador and Trinidad. Males are almost entirely emerald green, with white thighs, and blue hues sometimes visible in the face and breast. The bill is straight and black, and the dark, iridescent blue tail is forked, resting nearly even with the primaries when perched. Females are a lighter green above with gray underparts and limited green flanks. Dark auriculars between a white post-ocular stripe and the pale throat lend them a vaguely masked appearance. Females’ tails are less forked and pale-tipped. It often perches at low levels and forages with quick and direct flights to flowering trees or shrubs, and nectar piracy has also been observed.

Male 7·5–9·5 cm, female 6·5–7·5 cm. Male has short, straight, all-black bill (1.3–1.8 cm); forehead and crown iridescent golden-green, upperparts shining bronze-green; underparts glittering emerald-green, breast more iridescent than rest of underparts and has white thighs; tail steel blue, extent of fork varies slightly among some races. Female has bill black; bronzy green on forehead and crown, blackish band across ear-coverts bordered above by pale gray spot behind eye, rest of upperparts metallic grass-green; underparts pale gray; tail mainly blue-black, tipped whitish gray.

Juvenile resembles adult female, but is said to have duller olive-green crown, shorter postocular line, buff underparts, white vent and tarsal tufts.

Iris

black

Bill

entirely black

Tarsi and Toes

dark brown to blackish

Bill (mm)

duidae

exposed culmen: 13-14.5(mean 13.9) n = 5 males (Zimmer & Phelps 1952)

subfurcatus

exposed culmen: 12.5-14(13.2) n = 12 males (Zimmer & Phelps 1952)

caribaeus

exposed culmen:14.80±0.59, total culmen 16.93±0.91 n = 10 ♂♂, (Stiles 1996)

exposed culmen:15.47±0.72, total culmen 18.08±0.91 n = 6 ♀♀, (Stiles 1996)

phoeopygus

exposed culmen: 15.89±0.59, total culmen 17.91±0.83 n = 8 ♂♂, (Stiles 1996)

exposed culmen:15.90±0.64, total culmen 17.73±1.28 n = 6 ♀♀, (Stiles 1996)

Wing (mm)

duidae

44-49 (mean 47.7) n = 5 males (Zimmer & Phelps 1952)

46-49.5(47.7) n = 8 females (Zimmer & Phelps 1952)

subfurcatus

44-47 (45.4) n = 12 males (Zimmer & Phelps 1952)

44.5-46(45.5) n = 5 females (Zimmer & Phelps 1952)

caribaeus

43.69±1.03, n = 10 ♂♂, (Stiles 1996)

42.58±1.14, n = 6 ♀♀, (Stiles 1996)

phoeopygus

44.81±1.34, n = 8 ♂♂, (Stiles 1996)

42.47±0.48, n = 6 ♀♀, (Stiles 1996)

Tail (mm)

duidae

24-27.5(mean 25.9) n = 5 males (Zimmer & Phelps 1952)

25-27 (mean 26.4) n = 8 females (Zimmer & Phelps 1952)

subfurcatus

21.5-24(23.2) n = 12 males (Zimmer & Phelps 1952)

22.5-24(23.2) n = 5 females (Zimmer & Phelps 1952)

phoeopygus

21.36±1.08, n = 8 ♂♂, (Stiles 1996)

21.05±0.70, n = 6 ♀♀, (Stiles 1996)

caribaeus

21.25±0.89, n = 10 ♂♂, (Stiles 1996)

21.47±0.93, n = 6 ♀♀, (Stiles 1996)

Mass (g)

caribaeus

2.8, n = 1 ♀ (Thomas 1990)

2.3, n = 1 unsexed (Thomas 1982)

2.68±0.18, n = 6 ♂♂, (Stiles 1996)

2.54±0.23, n = 4 ♀♀, (Stiles 1996)

phoeopygus

2.73±0.25, n = 4 ♂♂, (Stiles 1996)

2.37±0.32, n = 3 ♀♀, (Stiles 1996)

2.6, n = 1 unsexed (Cotton 1998)

At times, the present species has been considered to include up to 17 subspecies (Bündgen 1999). Most of these taxa have, at one point or another, also been lumped together as races of other presently recognized species or considered full species on their own. These include the following taxa, recognized here as full species: C. auriceps, C. forficatus, C. canivetii, C. assimilis, C. gibsoni, C. olivaresi, and C. melanorhynchus. In addition there are a plethora of names that have been applied across the range of the genus that have been relegated to synonomy at various times, and also a variety of confusing hybrid and/or aberrant specimens. This rather checkered taxonomic past, along with confusing distribution and taxonomic issues within the "mellisugus complex" have led to many still debated and unresolved issues (Stiles 1996, Bündgen et al. 2019). See Nomenclature.

The six taxa included here as races of C. mellisugus all have black bills and shallowly forked tails in both sexes and are further characterized by males with glittering crowns and blue-tinged breasts and females with blue tails with a trace of dusky on the lateral rectrices. Nevertheless, several of the presently accepted races may be invalid, and further study is needed, especially in zones of possible contact (Bündgen et al. 2019).

Variation fairly subtle, very complex, and still not fully understood. Six subspecies recognized here.

Proposed race nanus of upper and middle Orinoco, at one stage placed in canivetii group (42 De Schauensee, R. M. (1966). The species of birds of South America and their distribution. Livingston Publishing Corporation, Wynnewood, Pennsylvania. Close ), may be best considered a synonym of caribaeus. Form napensis (= vitticeps), of R Napo in E Ecuador, indistinguishable from phoeopygus. Species formerly known as C. prasinus, when name mellisugus was erroneously thought to apply to Amazilia (Saucerottia) saucerottei braccata.

This widespread, polytipic species is found on most slands of the southern Caribbean (Aruba, Curaçao, Bonaire, Trinidad, and Margarita), through most of Venezuela, the Guianas, and into northern Brazil (43 Hilty, S. L. (2003). Birds of Venezuela. Christopher Helm, London, UK. Close , 44 Prins, T.G., Reuter, J.H., Debrot, A.O., Wattel, J. and Nijman, V. (2009). Checklist of the birds of Aruba, Curaçao and Bonaire, south Caribbean. Ardea. 97(2): 137–268. Close , 45 van Perlo, B. (2009). A Field Guide to the Birds of Brazil. Oxford University Press, New York, NY, USA. Close , 46 ffrench, R. P. (2012). A Guide to the Birds of Trinidad and Tobago. Third edition. Cornell University Press, Ithaca, NY, USA. Close , 47 Spaans, A. L., O. H. Ottema, and J. H. J. M. Ribot (2016). Field Guide to the Birds of Suriname. Brill, Leiden, The Netherlands. Close ). Along the eastern based of the Andes it is found from Colombia to northern Bolivia, extending eastward into western Brazil (48 Hilty, S. L., and W. L. Brown (1986). A Guide to the Birds of Colombia. Princeton University Press, Princeton, New Jersey, USA. Close , 49 Ridgely, R. S., and P. J. Greenfield (2001). The Birds of Ecuador. Volumes 1–2. Comstock Publishing Associates, Ithaca, New York, USA. Close ,50 Hennessey, A. B., S. K. Herzog, and F. Sagot (2003). Lista Anotada de las Aves de Bolivia. Fifth edition. Asociación Armonía/BirdLife International, Santa Cruz de la Sierra, Bolivia. Close , 45 van Perlo, B. (2009). A Field Guide to the Birds of Brazil. Oxford University Press, New York, NY, USA. Close , 51 Schulenberg, T. S., D. F. Stotz, D. F. Lane, J. P. O’Neill, and T. A. Parker (2010). Birds of Peru. Revised and updated edition. Princeton University Press, Princeton, NJ, USA. Close ).

From tropical to temperate zone, mainly between 750 and 2600 m in eastern Ecuador (phoeopygus) (49 Ridgely, R. S., and P. J. Greenfield (2001). The Birds of Ecuador. Volumes 1–2. Comstock Publishing Associates, Ithaca, New York, USA. Close ), mainly below 1200 m in E Peru (52 Schulenberg, T. S., D. F. Stotz, D. F. Lane, J. P. O’Neill, and T. A. Parker (2007). Birds of Peru. Princeton University Press, Princeton, NJ, USA. Close ) and no higher than 1850 m in Venezuela (43 Hilty, S. L. (2003). Birds of Venezuela. Christopher Helm, London, UK. Close ). Common in xerophytic habitats like savanna, cerrado, cultivated areas, plantations, town gardens, fields, hedgerows, large clearings in terra firme forest (5 Thomas, B. T. (1979). The birds of a ranch in the Venezuelan llanos. In Vetebrate Ecology in the Northern Neotropics (J. F. Eisenberg, Editor), Smithsonian Institution Press, Washington, DC, USA. pp. 213–232. Close , 24 Tostain, O., J. L. Dujardin, C. Érard, and J.-M. Thiollay (1992). Oiseaux de Guyane: Biologie, Écologie, Protection, Répartition. Société d’Etudes Ornithologiques & Laboratoire d’Ecologie Générale, Muséum National d’Histoire Naturelle, Brunoy, France. Close ,53 Restall, R., C. Rodner, and M. Lentino (2006). Birds of Northern South America: An Identification Guide. Christopher Helm, London, UK. Close ) and edges of deciduous woodland, but in Amazonian Ecuador is perhaps most frequent in várzea and floodplain forest (49 Ridgely, R. S., and P. J. Greenfield (2001). The Birds of Ecuador. Volumes 1–2. Comstock Publishing Associates, Ithaca, New York, USA. Close ).

Sedentary, but apparently with some poorly understood seasonal movements across altitude. In western Sucre (northern Venezuela) ssp. caribaeus species is reported to migrate into thorn forest from May to October (wet season), but elsewhere in this region it is present year-round (e.g., Hato Masaguaral, Guárico; Hilty 2003). Also, in southeastern Colombia (phoeopygus), the species was only observed from July to October (54 Cotton, P.A. (2007). Seasonal resource tracking by Amazonian hummingbirds. Ibis. 149(1): 135–142. Close ).

Trap-liner, but occasionally several individuals gather at flowering trees with other (usually larger) hummingbird species (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ), and in southeastern Colombia has been observed defending territory around patchs of flowers (54 Cotton, P.A. (2007). Seasonal resource tracking by Amazonian hummingbirds. Ibis. 149(1): 135–142. Close ).

Feeds at flowers at all heights above the ground, perhaps preferring those closer to the ground, but sometimes gathering in numbers at flowering trees (55 Meyer de Schauensee, R., and W. H. Phelps (1978). A Guide to the Birds of Venezuela. Princeton University Press, Princeton, NJ, USA. Close , 2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close , 56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ). Sometimes take nectar by piercing the petals of Laminaceae, or stealing nectar from holes around bases of flowers with long corollas (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close , 43 Hilty, S. L. (2003). Birds of Venezuela. Christopher Helm, London, UK. Close ). Insects are caught in the air by hawking.

In the Netherlands Antilles (caribaeus), Voous (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ) records the following plants: Tamarindus indica, Caesalpinia pulcherrima (Fabaceae), Albizzia lebbeck (Mimosaceae), Cordia alba, Cordia sebestena, Bourreria succulenta (Boraginaceae), Tabebuia chrysantha, Crescentia cujete (Bignoniaceae), Ipomoea incarnata (Convolvulaceae), Stenocereus griseus,, Opuntia wentiana (Cactaceae). Other recorded plants include Hibiscus, Lantana (43 Hilty, S. L. (2003). Birds of Venezuela. Christopher Helm, London, UK. Close ), Sesanum indicum (57 Haverschmidt, F. (1975). More bird records from Surinam. Bull. Brit. Orn. Club 95(2): 74–77. Close ), Palicourea crocea (Rubiaceae) (54 Cotton, P.A. (2007). Seasonal resource tracking by Amazonian hummingbirds. Ibis. 149(1): 135–142. Close ), Asclepias (Apocynaceae) (46 ffrench, R. P. (2012). A Guide to the Birds of Trinidad and Tobago. Third edition. Cornell University Press, Ithaca, NY, USA. Close ), Canna (Cannaceae), Odontoglossum bictoniense, Epidendrum brassavolae (Orchidaceae), Acacia tortuosa, Hibiscus rosa-sinensis, Poinciana regia, Leonotis nepetaefolia, and Bougainvillea spectabilis.

Feeds on small, soft-bodied arthropods in addition to nectar, and is known to take honeydew from Diaspididae found in bracaatinga trees (Mimosa bracaatinga). In a study in northeastern Venezuela (caribaeus), of 42 emetic samples from this species found minute invertebrates, particularly spiders (Araneae), flies (Diptera), and wasps (Hymenoptera) in 86% samples and nectar in 50% (58 Poulin, B., Lefebvre, G. and McNeil, R. (1994). Diets of land birds from northeastern Venezuela. Condor. 96(2): 354–367. Close ).

Song weak composed of repeated "tsip" or "chwep" notes, with occasional rolls or twitters (Restall et al. 2006). Calls include aelatively loud and harsh "chirrrt" (Voous 1983). Song a continuous series of subdued scratchy and wheezy notes, at a rate of 3–4 notes/second, recalling noise made by a high-speed shutter on a camera, and sometimes preceded by a few introductory notes, “witsitsitsi...chirr..chirr..chirr..chirr..” or “tsit-trr, tsit-trr, tsit-trr, tsit-trr...” (melanorhynchus/pumilus) (53 Restall, R., C. Rodner, and M. Lentino (2006). Birds of Northern South America: An Identification Guide. Christopher Helm, London, UK. Close ). Calls include a soft “tsip”, “pit” and “chwep”.

In northern Venezuela (caribaeus) appears to nest nearly year-round, perhaps with a peak in the late wet to early dry season (4 Schäfer, E., and W. H. Phelps (1954). Las Aves del Parque Nacional Henri Pittier (Rancho Grande) y sus Funciones Ecológicas. Boletín de la Sociedad Venezolana de Ciencias Naturales 16(83). pp. 165. Close ,6 Thomas, B. T. (1993). Birds of a northern Venezuelan secondary-scrub habitat. Bulletin of the British Ornithologists' Club 113(1):9–17. Close , 56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close , 59 Verea, C., A. Solórzano, M. Díaz, L. Parra, M. A. Araujo, F. Antón, O. Navas, O. J. L. Ruiz, and A. Fernández-Badillo (2009). Registros de actividad reproductora y muda en algunas aves del norte de Venezuela. Ornitología Neotropical 20(2):181–201. Close ). At least during April and May on Trinidad (1 Belcher, C. and G. D. Smooker. (1936). Birds of the colony of Trinidad and Tobago Part III. Ibis 66:1-35. Close ,46 ffrench, R. P. (2012). A Guide to the Birds of Trinidad and Tobago. Third edition. Cornell University Press, Ithaca, NY, USA. Close ). Nests with eggs in the former Netherlands Antilles virtually year-round (Feb, Mar, May, Jun, Oct and Dec) (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ,44 Prins, T.G., Reuter, J.H., Debrot, A.O., Wattel, J. and Nijman, V. (2009). Checklist of the birds of Aruba, Curaçao and Bonaire, south Caribbean. Ardea. 97(2): 137–268. Close ). The breeding of other subspecies is largely unknown.

Preferred nesting locations appear to be in dense, low, second-growth woodland c.0·8–0·9 m above ground, fixed on sloping branch (e.g., of Fleischmannia microstemon, Asteraceae)(2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ,56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ).

Cup-shaped nest (c.3 cm in diameter and 2.5 cm deep) composed downy plant material bound togther with spider webs and decorated externally with pieces of fine bark, lichen, and other vegetative detritus (1 Belcher, C. and G. D. Smooker. (1936). Birds of the colony of Trinidad and Tobago Part III. Ibis 66:1-35. Close ,2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ,56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ).

Clutch two white eggs, 11.3–12.75 × 7.4–8.25 mm, mass 0.4 g (1 Belcher, C. and G. D. Smooker. (1936). Birds of the colony of Trinidad and Tobago Part III. Ibis 66:1-35. Close ,60 Hellebrekers, W. P. J. (1942). Revision of the Penard oölogical collection from Surinam. Zoologische Mededelingen 24(10): 240–275. Close ,2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close ,56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close , 46 ffrench, R. P. (2012). A Guide to the Birds of Trinidad and Tobago. Third edition. Cornell University Press, Ithaca, NY, USA. Close ).

Incubation performed only by the female and lasts 13–19 days (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close , 56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ). Incubation constancy was 62% at one nest of caribaeus in northern Venezuela (56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ).

Young nestlings have dark grayish skin with two parallel dorsal rows of dark natal down, mass 0.2 g shortly after hatching (56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ). Nestlings fledge 18-20 days after hatching (2 Voous, K. H. (1983). Bird of the Netherlands Antilles. Foundation for Scientific Research in Surinam and the Netherlands, Antilles, Utrecht, The Netherlands. Close , 56 Thomas, B.T. (1994). Blue-tailed Emerald hummingbird (Chlorostilbon mellisugus) nesting and nestling development. Orn. Neotropical. 5(1): 57–60. Close ).

Not globally threatened (Least Concern). CITES II. Readily accepts man-made habitat. Generally considered to be common throughout much of its extensive range (61 Parker, T. A., D. F. Stotz, and J. W. Fitzpatrick (1996). Ecological and distributional databases. In Neotropical Birds: Ecology and Conservation (D. F. Stotz, T. A. Parker, J. W. Fitzpatrick, and D. K. Moskovits, Editors), University of Chicago Press, Chicago, Illinois, USA. pp. 113‒436. Close ), e.g. in upper Amazonia, Colombia, Venezuela and the Guianas, locally common on Bocas Is (between Trinidad and NE Venezuela), but thought to be generally uncommon and local on Trinidad (except NW peninsula), and absent on Tobago (62 Kenefick, M., Restall, R. and Hayes, F.E. (2011). Birds of Trinidad & Tobago. Second edn. Christopher Helm, London. Close ); uncommon to rare in E Ecuador (race phoeopygus) (53 Restall, R., C. Rodner, and M. Lentino (2006). Birds of Northern South America: An Identification Guide. Christopher Helm, London, UK. Close ). Blue-tailed Emerald is widespread and known to occur in a fair number of protected areas including Dinira National Park (caribaeus; Naveda-Rodríguez and Bisbal 2008), Amacayacu National Park (phoeopygus;54 Cotton, P.A. (2007). Seasonal resource tracking by Amazonian hummingbirds. Ibis. 149(1): 135–142. Close ), and the Pilón Lajas Biosphere Reserve (peruanus; 63 Hennessey, A. B., S. A. Herzog, M. Kessler, and D. Robinson (2003). Avifauna of the Pilón Lajas Biosphere and Communal Lands, Bolivia. Bird Conservation International 13(3):319–349. Close ).