The term Olive-green tanager refers descriptively to several species of birds within the family Thraupidae, particularly those belonging to the genus Chlorothraupis. While not a single, universally recognized primary common name for a specific species, it accurately describes the predominant plumage coloration of several related tanagers, which are characteristically dull olive-green.
Taxonomy and Nomenclature
The genus Chlorothraupis, sometimes referred to as "bush-tanagers" or "Carmiol's Tanagers," comprises four species, all exhibiting varying shades of olive-green plumage:
- Chlorothraupis carmioli (Carmiol's Tanager): Found in Central America.
- Chlorothraupis frenata (Dusky-faced Tanager): Distributed in the Andes of South America, often previously considered a subspecies of C. olivacea.
- Chlorothraupis olivacea (Olive Tanager): Occurs in the Chocó region of northwestern South America.
- Chlorothraupis stolzmanni (Ochre-breasted Tanager): Found in the western Andes of South America.
The descriptive term "olive-green tanager" is most frequently applied to members of this genus due to their shared morphological characteristics and coloration. For instance, Chlorothraupis olivacea is officially known as the Olive Tanager, highlighting its characteristic color.
Description
Birds described as "olive-green tanagers" are typically medium-sized, robust passerines, generally ranging from 17 to 20 cm (6.7 to 7.9 inches) in length. Their most distinguishing feature is their predominantly dull olive-green plumage covering the back, wings, and underparts. Some species may exhibit subtle variations, such as a dusky or grayish face (C. frenata), a yellowish throat, or an ochre wash on the breast (C. stolzmanni). Sexual dimorphism is often minimal or absent, with both males and females sharing similar coloration, though females might be slightly duller in some species. They typically have relatively thick, conical bills suited for their varied diet.
Habitat and Distribution
These tanagers inhabit humid tropical and subtropical forests, usually found in the understory or mid-story vegetation. Their distribution spans from Central America (for species like C. carmioli) through the Andes and lowlands of northwestern South America (for species like C. frenata, C. olivacea, and C. stolzmanni). They prefer dense foliage and often frequent forest edges, clearings, and mature secondary growth.
Diet and Behavior
Olive-green tanagers are omnivorous, with their diet primarily consisting of insects and small fruits. They are often observed foraging actively within the forest canopy and undergrowth. These birds are generally inconspicuous and can be challenging to spot due to their drab coloration blending with the dense foliage. They are frequently encountered as members of mixed-species foraging flocks, moving with other tanagers, warblers, and various small forest birds. Their calls are typically harsh chirps or churrs.
Conservation Status
The conservation status of the species commonly described as olive-green tanagers varies. Most species within the Chlorothraupis genus are currently listed as Least Concern by the IUCN, indicating stable populations. However, like many forest-dwelling birds, they face localized threats from habitat loss and degradation due to deforestation for agriculture, logging, and infrastructure development.