Yellow-throated Toucan Ramphastos ambiguus

  • Order: Piciformes
  • Family: Ramphastidae
  • Polytypic: 3 subspecies
  • Authors: Ari A. Rice, Jason D. Weckstein, and J. Engel
Sections

Behavior

Behavior

Locomotion:

The flight of Yellow-throated Toucan is slow and undulating. Flies with rapid, shallow wingbeats followed by glides (Stiles and Skutch 1989). Often perches horizontally. Because of their size and general lack of predators, Yellow-throated Toucans often spend up to several hours resting and foraging in a single tree (Howe 1977). When foraging, hops nimbly among branches as it feeds on fruits (Ridgely and Greenfield 2001).

Calling:

Yellow-throated Toucans frequently call from a tall, exposed perch above the canopy (e.g., a dead, emergent tree) and pairs will often chorus together near dawn and dusk. Calls are usually given with a vertical head movement: the head is thrown up on the first note and gradually lowered (Short and Horne 2001). In eastern Ecuador and in Peru, apparently warier and less vocal than other species of Ramphastos (Ridgely and Greenfield 2001, Schulenberg et al. 2007).

Self-maintenance:

Yellow-throated Toucans spend a considerable amount of time preening, resting, scratching, and exhibiting "comfort behavior." Preening is mostly with the bill, although the enormous bill size and shape can be somewhat limiting. For this reason, allopreening is common. Pairs often sit next to each other and take turns preening each others’ head and neck feathers. Clayton and Cotgreave (1994) also noted a Yellow-throated Toucan scratching and rubbing its face against a tree limb- presumably to get rid of skin parasites.

Yellow-throated Toucans usually bathe in water-filled hollows or crevices in trees, and when sleeping will bend their tails backwards over their heads (a trait known only in toucans) (Short and Horne 2002).

Territoriality

Yellow-throated Toucans do not hold territories per se, but often dominate favored fruit trees, using aggressive displays to drive away rivals, other birds, smaller toucans, and even mates. Pairs usually occupy and defend neighboring trees, although a male will sometimes present his tree as a "gift", allowing the female to feed from it (Short and Horne 2001).

Sexual Behavior

Yellow-throated Toucans are believed to form long-term pair bonds, although this needs to be further studied. Pairs often allopreen and "courtship feed", where the male feeds the female regurgitated fruit. Sometimes, a male presents the female with a fruiting tree that he is guarding from other intruders, allowing her to feed in it or even take control while he moves to a nearby tree (Short 2002). Copulation takes place without preliminary displays (Short and Horne 2001).

Social and interspecific behavior

Yellow-throated Toucans usually forage in pairs or small groups, although they may gather in larger numbers where food is plentiful (Hilty and Brown 1986, Stiles and Skutch 1989, Short and Horne 2001). At feeding sites, they compete heavily with other frugivores and can be quite aggressive, displacing other birds. In one study, Yellow-throated Toucans were responsible for 11 of 15 instances of interspecific aggression (Chang et al. 2008). The majority of victims were oropendolas (Psarocolius), araçaris (Pteroglossus), and other species of Ramphastos, all of which are, as Chang et al. noted, species that share similar diets. Intraspecific aggression also occurs, but may be less common. Because of their large size, Yellow-throated Toucans exhibit dominance over other toucan species such as Keel-billed (Ramphastos sulfuratus) and Choco (Ramphastos brevis) toucans. They sometimes feed in mixed-species flocks, although Yellow-throated Toucans often displace smaller Keel-billed Toucans after following them to a food source (Short and Horne 2001).

Despite agonistic interactions at food sources, Yellow-throated Toucans nesting in proximity to Keel-billed Toucans do not exhibit aggressive behavior near the nest site. One record from Barro Colorado Island (Panama) showed both species nesting within 17 m of each other (Skutch 1972).

Little is known about the visual, aesthetic, or functional purposes of Yellow-throated Toucan’s large and gaudy bill. Recent research has shown that the congener, Toco Toucan (Ramphastos toco), can modify the amount of blood flow to its bill and can thus use its bill as a thermal radiator to distribute heat away from its body (Tattersall et al. 2009). However, this does not imply that the extremely large bills of these birds evolved for this purpose. The large bill may also help the bird while raiding other species’ nests (Short and Horne 2002). As Skutch (1972) recalls: "I have never seen even the boldest flycatcher, enraged by the violation of its nest, dare to come within range of a perching toucan’s beak; even small hawks are, as we have seen, intimidated by it." Most birds, however, will attack and harass toucans that come within range of their nests. Boat-billed Flycatchers (Megarynchus pitangua), which Skutch refers to as having a "moral antipathy" towards toucans, readily meet and harass a toucan in mid-flight (Skutch 1972). Perhaps the bill plays a role in inter and/or intraspecific social interactions but there are no data to support or refute this hypothesis.

Predation

Little is known about predation on this species. Because of their large size, Yellow-throated Toucans probably have very few, if any, regular predators. Some larger species of raptor may prey on adults, although this probably is rare in occurrence.

When feeding in a mixed flock setting, Yellow-throated Toucans tend to ignore the alarm calls of smaller birds (Howe 1977).

Recommended Citation

Rice, A. A., J. D. Weckstein, and J. Engel (2010). Yellow-throated Toucan (Ramphastos ambiguus), version 2.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.bkmtou1.02