Blue-and-black Tanagers (Tangara vassorii) are vibrantly-colored, tropical birds that occur in the Andes of northwestern South America from Venezuela to Bolivia. They live at higher elevations than any other species of Tangara (Isler and Isler 1987). There are three subspecies, all of which occur in the upper montane evergreen forest, elfin forest, and tall secondary growth forest in the Andes (Parker et al. 1996, Isler and Isler 1987). Their diet consists of a variety of fruits as well as some insects. Rarely found alone, they live mostly in mated pairs and regularly join large mixed species flocks when foraging at abundant sites. There is little information regarding their behavior, population dynamics, and demography. The conservation status of the Blue-and black Tanager is listed as a species of Least Concern by the IUCN. Furthermore, the Blue-and-black Tanager has been described as "fairly common" (Parker et al. 1996), although there is currently no quantifiable information regarding the population size or trend of the species.
Similar to other Tangara species, the Blue-and-black Tanager has a diet consisting mostly of fruits and arthropods. This species is especially fond of the flowering plant, Miconia, and other fruits produced by the Melastomataceae. In a comparative study of Tangara diets and foraging behavior, Naoki (2003) found that all fruit taken by T. vassorii were in the genus Miconia. The Blue-and-black Tanager was the only Tangara, among 25 species studied, that feed solely on fruit in a single genus. Isler and Isler (1987) summarized stomach contents for this species and found vegetable matter listed for 14 individuals and animal matter listed for three individuals. Specific items listed include fruit pulp, seeds, berries, insects, and seeds of melastome fruits.
Locomotion: Described as active, spritely, and restless, the Blue-and-black Tanager hops quickly along branches and flutters through foliage, rarely spending most of its time in one area (Isler and Isler 1987).
Foraging: The Blue-and-black Tanager can forage at all levels and in a fast-paced manner (Restall et al. 2007), with the canopy being the preferred foraging strata (Parker et al. 1996). This tanager forages from low in bushes to the tallest tree crowns though they typically stay high in the trees within forest (Isler and Isler 1987). When foraging for arthropods, the Blue-and-black Tanager searches several different substrates and uses several differnt methods to find their prey. Isler and Isler (1987) summarized several of these generally. They sometimes hop along moss-covered branches, and they use the diagonal-lean method to search for prey on the undersides branches, the top and bottom surfaces of leaves, clumps of moss, and small bromeliads. They also are described as hanging upside down to inspect leaves, petioles, and bunches of dead twigs for prey items. Naoki (2003) quantified various arthropod foraging modes and substrates for Tangara vassorii and a number of other Tangara species. The most common attack modes used by T. vassorii are: reach-down (28%), glean (25%), and reach-out (13%). Hang-upside down was used in only 9.4% of the observations. The most common substrates searched were partially moss covered branches (43%), bare branches (19%), and leaves (19%). For fruit foraging, Isler and Isler (1987) mention that this species will lean down to reach out and snap up berries in a rapid motion and subsequently sit upright while eating on the berry. In Naoki's (2003) study, the most common fruit foraging modes were gleaning (72%), reach-out (21%), and reach-down (7%).
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