Diet and Foraging

Red-billed Ground-Cuckoos are probably primarily insectivorous, although, some plant material also is eaten (Payne 2005).

For example, they have been observed eating a variety of fruits discarded by foraging tamarins. Species consumed by Red-billed Ground-Cuckoos included Inga punctata, Salacia juruana, Abutta sp., Rheedia sp., Sapotaceae, Flacourtaceae, Leguminosae, Hyppocrataceae, Mrytaceae, and Menispermaceae. They have also been recorded eating the fecal droppings of foraging tamarins that contained fruit seeds (Siegel et al. 1989). See Foraging Behavior.

Red-billed Ground Cuckoo has been observed foraging in association with Brown-mantled (Saguinus fuscicollis) and Moustached tamarins (S. mystax; Callitrichidae, Primates) at Estación Biológica Quebrada in northeastern Amazonian Peru. Descriptions of the behavior from Siegel et al. (1989) are as follows:

The behavior was observed in forest habitat where the canopy height was approximately 20 m with some taller and emergent trees (25-30 m). The visibility at eye level was about 10-15 m, being obscured primarily by palms (including Lepidocarium tessmani, Geonoma sp., and Chamaedora sp). There were three occasions of observation that lasted 40 min, 5 hr, and 7 hr. The same tamarin troop was observed in all cases because they occurred within the same area of their home range, but it was not known if the same cuckoo participated each time.

The tamarins moved through the canopy or between the tree trunks at heights of 0.3-25 m. The cuckoo walked or ran on the ground directly below or somewhat behind the tamarins, and it made its bill-snapping call as it moved (see Nonvocal Sounds). The cuckoo was observed picking up from the ground and feeding on fruits that were used or partially used by the tamarins (see Diet). It also consumed insects that were flushed by the movements of the tamarins in the trees. See Behavior for more behavior exhibited by Red-billed Ground-Cuckoo in association with tamarins that is not related to foraging.

One Red-billed Ground-Cuckoo was observed following an army ant swarm (Eciton burchelli) in Colombia in order to take advantage of the insects and other small prey items that were disturbed and escaping from the marauding ants. It walked and ran on the ground and low logs in pursuit of prey. When it detected the observer, the cuckoo snapped its mandibles, raised its crest, and lifted its uptilted tail about 10° before leaping horizontally more than 1 m into the cover of the vegetation (Willis 1982). There have also been two observations of Red-billed Ground-Cuckoos near army ant swarms in Ecuador; in one case, a pair of cuckoos were seen foraging together (López-Lanús 1999, Ridgely and Greenfield 2001). Red-billed Ground Cuckoos producing a bill snapping mechanical sound (Todd 1925) when following ant swarms in the company of antbirds; see Sounds and Vocal Behavior.

In addition, Red-billed Cuckoos probably follow groups of peccaries (e.g., Collared Peccary Pecari tajacu), as do other Neomorphus species, to feed opportunistically on prey disturbed by their movements through the forest; there is one possible report of this behavior in Ecuador (López-Lanús 1999). See Nonvocal Sounds.