The Ruby-crowned Tanager (Tachyphonus coronatus) is omnivorous and typically forages near the ground at forest edges, but also midstory to the canopy (Isler and Isler 1987, Rodrigues 1995, Anciães and Marini 2000). In 71 foraging observations, 62.5% of arthropods and 54.8% of fruits were taken from low story (Rodrigues 1995). Of 18 fecal samples all contained fruits with 3 also containing insects (Silva and Gomes 2002). They peer into vegetation as they search for arthropod prey (Hilty 2011). They will perch and reach to pick fruits (Isler and Isler 1987, Robinson 2015), and hang upside down in inflorescences (Marcondes-Machado and Olivera 1987). They are very active foragers, often seen hopping low in shrubs or plant bases in order to pick fruit (Isler and Isler 1987, Ridgely and Tudor 1989). Depending on the fruit, they may eat the seeds, mash or cut the fruit with their bill to get pulp and juices, take the fruit away in their crop, eat around the seeds, or eat the fruit whole and regurgitate the seeds later (Foster 1987, Isler and Isler 1987, Côrtes et al. 2009, Robinson 2015). Stomach contents (n=22) showed 8 birds ingesting animal matter, 1 bird with vegetable matter, and 13 with both (Moojen et al. 1941, Isler and Isler 1987). Typically they eat more insects than fruits (Foster 1987), for example, 67% of stomachs examined (n=6) contained arthropods, and 50% contained fruits (Gomes et al. 2010). This is not always the case, for analysis of 37 fecal samples showed that 87% of their diet was frugivorous (Hasui et al. 2007).
Plant material consumed is here described in detail. It has been seen feeding on fruit and/or flowers of species of Sapindaceae, Allophylus edulis (Isler and Isler 1987); Melastomataceae, such as Miconia rigidiusula and Leandra barbinervis (Rodrigues 1995); Rubiaceae such as Palicourea longepedunculata and Alibertia myrciifolia (Silva et al. 2010, Muscat et al. 2014); Myrtaceae such as Eugenia umbelliflora; Primulaceae species such as Myrsine lancifolia and M. ferruginea (Rodrigues 1995, Guerta et al. 2011); bromeliads such as Neoregelia, Aechmea lindenii (Lenzi et al. 2006) and Nidularium; Poaceae seeds of Guadua tagoara (Pachecho et al. 2014); Sulanaceae such as Solanum mauritianum (Robinson 2015); Euphorbiaceae such as Alchornea glandulosa and A. triplinerria where it would consume the fruits of the latter then eat the seed aryls (Zimmerman 1996, Pascotto 2006, Parrini and Raposo 2010, Parrini and Pacheco 2011); picking the fruits of Talauma ovata (Magnoliaceae); Piper sp. and Syagrus romanzoffiana in the Piperaceae and Arecaceae respectively (Rongetta 2010); melastomes, Cecropia (Belton 1985, Marcondes-Machado and Olivera 1987), Eucalyptus flowers, palm fruits such as Euterpe edulis, and Ficus; as well as persimmons, papayas, oranges, and bananas at feeders; and will also eat leaves (Belton 1985, Isler and Isler 1987, Cazetta et al. 2002, Fadini and de Marco Jr. 2004, Côrtes et al. 2009, Bencke 2010, Cestari 2010, Cintra 2016). They are known to consume the fruits and disperse seeds of introduced species such as the Black Mulberry (Morus nigra) and West Indian Raspberry (Rubus rosifolia), in the Moraceae and Rosaceae respectively (Ribeiro da Silva et al. 2015). A study targetting foraging observations at fruiting species in southeastern Brazil found the Ruby-crowned Tanager to be among the most frequent birds recorded eating fruits, with 61 observations of from 14 species of plants: Amaranthaceae, Chamissoa altissima, 5 observations (obs.); Boraginaceae, Cordia sp., 1 obs.; Cactaceae, Pereskia aculeata, 1 obs., and Rhipsalis sp., 1 obs; Cecropiaceae, Cecropia pachystachia, 16 obs.; Cucurbitaceae, Momordica charatia, 1 obs.; Euphorbiaceae, Pera glabrata, 7 obs.; Meliaceae, Trichilia clauseni, 3 obs.; Myrtaceae, Gomidesia affinis, 1 obs.; Rosaceae, Rubus sp., 1 obs.; Solanaceae, Cestrum sp., 1 obs.; Ulmaceae, Trema micrantha, 10 obs.; Urticaceae, Urera baccifera, 12 obs.; and Verbenaceae, Lantana sp., 1 obs (Galetti and Pizo 1996). A similar study also found them among the most common and important frugivore, foraging on Melastomataceae species Miconia cinnamomifolia 5 obs., M. tentaticulifera 5 obs., and M. budlejoides 1 obs.; Cecropiaceae Cecropia glaziovii 2 obs.; Flacourtiaceae Casearia sylvestris 1 obs.; and Symplocaceae Symplocos pubescens 1 obs. (Fadini and de Marco Jr. 2004). Observations at fruiting Eugenia umbelliflora found that all exits flights from the fruiting tree were towards low restinga habitat (Côrtes et al. 2009). A Ruby-crowned Tanager will chew flowers when eating a yellow Bignoniaceae vine or remove sepals and petals of Inga (Willis 2002). Seeds were found in 17/18 bird’s fecal sample suggesting they are important to the dispersal of seeds in the area (Gomes et al. 2011), and the seeds of Solanum granuloso-leprosum have been shown to germinate after passing through their gut (Jacomassa and Pizo 2010).
Ruby-crowned Tanagers will pursue terrestrial invertebrates in the orders Orthoptera, Coleoptera (e.g. weevils and leaf beetles), and Hemiptera such as plant lice (Moojen et al. 1941, Isler and Isler 1987). Typically they glean insects from leaves (64.5% of 31 observations) and branches (19.4%), but also from moss and the ground (Rodriques 1995). This species was found at 47% of army ant swarms (23 of 49 swarms), including swarms of the ant species Labidus praedator and Eciton burchelli (Faria and Rodrigues 2009). They follow these army ants near the edge of the ant swarm to capture invertebrates that are displaced from the ants (Faria and Rodrigues 2009). A male and female were among the bird species attracted to a termite hatch, catching the winged adults in short flights (Gussoni and Campos 2003). Also, they forage on honey dew, the sugary excretions of scale insects (Teixeira et al. 2013).