Order
Passeriformes
Family
Thraupidae
Genus
Dacnis
 
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Version 1.0

This is a historic version of this account.  Current version

SPECIES

White-bellied Dacnis Dacnis albiventris

Arisa Iga, Casey H. Richart, and Kevin J. Burns
Version: 1.0 — Published April 15, 2017

Appearance

Distinguishing Characteristics

White-bellied Dacnis (Dacnis albiventris) a small lowland tanager with a short tail and a conical black bill which is among the shortest in the genus (Hilty and Brown 1986). Like most Dacnis, males are striking and females are dull green. Males are primarily cobalt blue, with a black mask, yellow iris, and white belly. Females are yellowish olive above and slightly brighter below.

Similar Species

Males of the dichromatic White-bellied Dacnis usually are easily distinguished from other species of Dacnis by the combination of the black mask not extending past the auriculars and by being darker blue. It is probably most similar to Black-faced Dacnis (Dacnis lineata) in that both species are blue and black above, white below, and have bright yellow iridies; White-bellied Dacnis however is darker blue instead of turquoise, has a blue mantle instead of black, and the black on the face does not extend posterior to the auriculars (Ridgely and Tudor 1989). The male is perhaps more easily confused with certain species of Tangara, such as Turquoise Tanager (Tangara mexicana) and Masked Tanager (Tangara nigrocincta), as well as with Hooded Tanager (Nemosia pileata). White-bellied Dacnis and Turquoise Tanager are both primarily cobalt blue anteriorly, however Turquoise Tanager does not have a black mask and yellow irides; instead it has an all blue face, black eyes, a black nape, and the center of the belly is yellow (Hilty and Brown 1986, Ridgely and Tudor 1989, Hilty 2011). White-bellied Dacnis and Masked Tanager are both primarily dark blue and black above, and white or pale colored below, however, the White-bellied Dacnis is darker blue on its body, the black mask extends to the auriculars, and has a blue nape and mantle, whereas in Masked Tanager the black mask encompasses the lores and just around the eyes, and the upper breast and mantle are black (Clements and Shany 2001, Hilty 2011). Both White-bellied Dacnis and Hooded Tanager have black on their face, yellow iridies, and are darker above; however, in Hooded Tanager, the black extends onto the crown, the upperparts are gray not blue, with a white forecrown, and Hooded Tanagers are more extensively white below (Hilty and Brown 1986, Hilty 2011). Female White-bellied Dacnis are primarily dull green, and much less striking than the adult male. They are most likely to be confused with female Black-faced Dacnis and Yellow-bellied Dacnis (Dacnis flaviventer). White-bellied Dacnis female is more yellow, and less dull green than either of these species, and has a darker olive iris rather than yellow (Ridgely and Tudor 1989, Hilty 2011). They perhaps are best differentiated by their accompanying male.

Detailed Description

White-bellied Dacnis has a short, conical, and pointed bill, and a short tail (Hilty 2011). The adult male is remarkably bright cobalt blue on the crown, nape, mantle, back, throat, and breast. This blue surrounds a distinctive angular black mask that includes the lores and auriculars (Hilty 2003, Hilty 2011). The scapulars are typically black, framing the cobalt mantle (Hilty 2011). They are horizontally cut white across the breast, which extends to the undertail coverts, with the flanks often appearing gray with clouded lighter blue spotting (Hilty 2003, Hilty and Brown 1986, Hilty 2011). The underwing coverts are white (Hilty and Brown 1986). The lesser upperwing converts are mostly cobalt-blue, the median and greater coverts are black largely edged cobalt, and the primary coverts and flight feathers are also black edged blue; the tail is black (Hilty 2011). The outer part of the tertials are cobalt, the inner part dusky (Hilty 2011).

The adult female is very different, primarily dull olive above and yellowish below. Females are olive brown on most of the head, through the nape, mantle, and back, fading to distinctly greener on the rump; and olive brown on the primary and secondary coverts, and the edging of the remiges, with darker lores (Hilty 2003, Hilty and Brown 1986, Hilty 2011). They are dull greenish yellow below; the center of the belly is yellower, and the throat is grayish white (Ridgely and Greenfield 2001, Hilty 2003, Hilty and Brown 1986).

Immatures are similar to adult females. However, their primary and secondary coverts are browner, and the remiges and rectrices of immature males are more blackish (Hilty 2003, Hilty 2011). Though the sexes are obviously dichromatic, they likely look more dissimilar to each other, for the plumage of both sexes is highly reflective in the UV spectrum and this color is dichromatic (Burns and Shultz 2012).

Molts

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 performative molt is partial in Dacnis (Ryder and Wolfe 2009). Although an immature plumage is described for White-bellied Dacnis (Sick 1960, Hilty 2011), more specific information on molt and its timing is not available for this species.

Bare Parts

The bill is blackish (Hilty 2011). The iris is bright golden yellow in adult males, light brown to grayish brown in females, and grayish yellow in older immature males (Hilty 1999, Restall et al. 2007). The tarsi and toes are gray (Hilty 2011).

Measurements

The total length is 10-10.9 cm (Isler and Isler 1987, Hilty 2003). The mass is 11-11.5 g (Sick 1960, Isler and Isler 1987).

Recommended Citation

Iga, A., C. H. Richart, and K. J. Burns (2017). White-bellied Dacnis (Dacnis albiventris), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.whbdac1.01