A new feeding association between black-goggled tanagers (Tachyphoninae) and black lion tamarins (Primates, Callitrichinae)

Insectivorous-frugivorous birds have been described to benefit from multiple forms of interspecific feeding associations. Here we present quantitative data on a new feeding association between the black-goggled tanager (Trichothraupis melanops) and an endangered frugivorous-faunivorous neotropical primate, the black lion tamarin (Leontopithecus chrysopygus), at an Atlantic Forest remnant in São Paulo state, Brazil. Using scan data from full day follows with a group of lion tamarins, we investigated if the behaviors displayed by the primates influenced the presence, behavior, and proximity of the tanagers. We observed the black-goggled tanagers to activelly follow the primates during the day, always positioned below the primates, and to capture insects flushed by the lion tamarins’ foraging activities. We found that black-goggled tanagers associated significatively more with black lion tamarins in the early hours of the day (i.e., from 6:00 to 8:59 a.m.) and when the primates were feeding/foraging. We found no evidence that the black lion tamarin benefits or incurs costs from associating with the tanagers, suggesting a new record of commensalism.