The ocellated antbird is the largest antbird, with a long bill and tail. Females usually weigh 44-50g and measure 177-203mm in total length, while males weigh 50-58g on average and measure 174-202mm. Their backs and chests are a reddish-brown color and are covered in black spots. They have black feathers on their throats, a grey crown, and bare blue skin around their eyes. Juveniles have crowns made up of black feathers with white tips. Their faces are duskier and not as bright blue as those of adults, and they also lack the rust coloring in the breast and belly (Willis 1973).
Males copulate with females after many courtship feedings, when the female allows it. Nests are built in old growth forests on the ground between the buttresses of large trees and are cup-shaped, made up of small twigs and dried vines. Clutch size is usually two, and both males and females incubate the eggs (Willis 1973). Both parents also feed the nestlings, bringing them prey from the ant swarm at which they forage (Class and Chaves-Campos 2009). Nest success tends to be low, with an estimated survival of 4.2%. Nest predators include snakes and hawks (Willis 1973).
Ocellated antbirds seem to be very susceptible to forest fragmentation. Willis (1973, 1974) reported the decline of the species from 1960 to 1971 in Barro Colorado Island in Panamá, a mountaintop that became an island with the construction of the Panamá Canal around 1914. Annual mortality rate was 30% for adults in the late 60’s and early 70’s (Willis 1974) and the population in this 1500 ha island has already declined to complete extinction (Robinson 1999).The likely reason for this local extinction is that the large body of water surrounding the island has become an effective barrier for dispersal of ocellated antbirds (Robinson 1999, Chaves-Campos and DeWoody 2008). Populations of ocellated antbirds seem to be healthier in larger protected areas (Chaves-Campos and DeWoody 2008).
The Ocellated antbird (Phaenostictus mcleannani) is a neotropical bird that can be found in the understory of lowland humid forests, ranging from southeastern Honduras to northwestern Ecuador (Willis 1973). Adults sport spotted plumage on their chests and back, black throats with a red-orange breast area that fades to brown, a grey crown, and bare blue skin around the eyes (Willis 1973). The diet of this species consists mainly of insects and arthropods, which they catch by following army ants, given that these ants tend to flush other insects out from their hiding places (Stiles and Skutch 1989). Ocellated antbirds mate for life and keep roosting and feeding territories. Nests are placed between the buttresses of trees and both parents take turns incubating and feeding their young (Class and Chaves-Campos 2009). Young Ocellateds gain foraging independence by 6 weeks, and after around six months (if female) or longer (if male), they leave their parents to establish their own roosting site with a mate (Willis 1973).
The ocellated antbird’s natural habitat is the understory of lowland humid forests. They can be found from east Honduras to northwest Ecuador, and are endemic to the tropics in the Americas (Willis 1973). It is primarily restricted to lowland Caribbean forests in Central America, and its elevational range in Costa Rica is sea level to 1200m. They are nonmigratory (Stiles and Skutch 1989).
Ocellated antbirds occur mainly in the undergrowth of humid lowland forests, usually preferring old growth forests. They rarely cross open areas an can often be found wandering in the undergrowth when not following ant colonies. Birds tend to occupy “home ranges” of about 6ha (Chaves-Campos and DeWoody 2008) within which the build a nest and lay eggs (Class and Chaves-Campos 2009). They tend to avoid areas with exposed undergrowth and little leaf litter and tend to show a preference for sloped forests in Panamá (Willis 1973), but not in Costa Rica (Chaves-Campos and DeWoody 2008).
Ocellated antbirds occur mainly in the undergrowth of humid lowland forests, usually preferring old growth forests. They rarely cross open areas an can often be found wandering in the undergrowth when not following ant colonies. Birds tend to occupy “home ranges” of about 6ha (Chaves-Campos and DeWoody 2008) within which the build a nest and lay eggs (Class and Chaves-Campos 2009). They tend to avoid areas with exposed undergrowth and little leaf litter and tend to show a preference for sloped forests in Panamá (Willis 1973), but not in Costa Rica (Chaves-Campos and DeWoody 2008).
Ocellated antbirds are terrestrial and understory foragers, eating a diet of terrestrial invertebrates and vertebrates (Willis 1973, Class and Chaves-Campos 2009). They forage by sallying and are also obligate army and followers and do not forage outside of army ant swarms. Their foraging strategy is to follow army ant colonies in order to catch and eat whatever arthropods the colony flushes out of their hiding places as it swarms. Mated pairs forage within their respective “feeding ranges” which tend to overlap with other birds’ feeding ranges (both Ocellated and other antbird species), and foraging occurs on a daily basis (Chaves-Campos and DeWoody 2008). Close relatives have been shown to feed together, and neighboring birds have also been shown to take advantage of the knowledge of ant colony movement of other birds. These behaviors include travelling in groups and following birds that leave a feeding patch, travelling in a focused manner (suggesting that they are not wandering and looking for ants, but that they or another member of the group knows where the ants are), and using faint songs when leaving a swarm to alert others that they are going to another one. Loud songs can also be used to lead birds to ant swarm, as it is usually emitted when birds are not in view of each other. This system can be considered “a network of spatial knowledge” in which bird pairs interact with neighbors in order to gain access to and find more ant colonies (Chaves-Campos 2011).
Mates
Ocellated antbirds are monogamous and mate for life. There are three components to courtship between the male and the female, which are loud singing, courtship feeding, and traveling together. Males court females by bringing them food, and after multiple feedings the female will allow the male to copulate with her. Mates always travel and forage together unless the female has laid eggs, in which case they will take turns, with one partner incubating while the other forages (Willis 1973, Class and Chaves-Campos 2009). If a male loses his mate, he will loud-sing repeatedly until the female replies, at which point they will sing to each other until they come together again (Willis 1973).
Social behavior
Pairs of ocellated antbirds and their offspring often roost and feed together. Pairs tend to have a feeding range of about 50ha and a roosting and nesting area of about 6ha, which is usually located in the center area of the feeding range. Roosting areas are surrounded by neighboring roosts from other pairs, causing feeding ranges to overlap and for roosting neighbors to aggregate at the same swarms (Chaves-Campos and DeWoody 2008). Males tend to respond aggressively to other males that infringe on their roosting areas, however a study done by Chaves-Campos et. al. (2009) has shown that these responses are less aggressive when directed towards adjacent neighbors versus non-neighbors. Pairs also often compete for access to perches at the front of ant swarms, however they were found to tolerate the presence of nearby neighbors at the fronts, while chasing off more distant neighbors (Chaves-Campos et. al. 2009).
Calls
Ocellated antbirds have a variety of different calls. These include chirring (a loud buzzing in reaction to terrestrial mammals animals), keening (reaction to a distant and uncertain danger), chipping (call given when a bird flees for cover), grunting (made towards competitors when they come too close), loud-songs (given when mates are separated or when a bird leaves a swarm), faint-songs (when a group of birds is about to travel), serpentine songs (used to attract a mate or young to a feeding site), whirring and snapping (made by dominant birds towards subordinates), chittering (made by subordinate birds to dominant ones), whining (made by a subordinate bird as it attempts to avoid being chased away from a swarm), and caroling (sung when a male or female is feeding a young bird or when a male is feeding a female) (Willis 1973). Calls can be used to display aggression, to let other birds know that one is departing an ant swarm in search of another, and to draw birds towards a swarm (Willis 1973, Chaves-Campos 2011).
The ocellated antbird (Phaenostictus mcleannani) is a species of antbird in the family Thamnophilidae. It is monotypic within the genus Phaenostictus and is found in southern Central America and the northwestern part of South America. Its natural habitat is the understory of tropical moist lowland forest, foothill forest, and tall secondary growth woodlands.
The species is 19 cm long and weighs around 50 g. The eye is surrounded by a large area of bare blue coloured skin. The plumage varies slightly amongst the three subspecies, but overall it has a grey crown, black throat with a buff breast changing into a spotted belly and back.
The bird feeds primarily on insects, arthropods, and sometimes on small lizards. Most of its prey is obtained from trails of army ants, which flush the prey from hiding places. One such army ant species is Eciton burchellii. The ocellated antbird is considered an obligate follower of army ants, seldom foraging away from swarms. Amongst the species of antbirds and other army ant followers (such as tanagers and woodcreepers) it is usually a dominant species.
The social biology of this species is unusual for the antbird family. The breeding pair form the nucleus of a group or clan that includes their male offspring and their mates. These clans work together to defend territories against rivals. The open nest cup was only recently described, with a clutch of two eggs.[2]
The ocellated antbird was formally described in 1861 by the American amateur ornithologist George Newbold Lawrence and given the binomial name Phlogopsis mcleannani (misspelled as Meleannani). The specific epithet honours James McLeannan, a railway engineer on the Panama Canal Railway, who had collected the specimen in Panama.[3] The ocellated antbird is now placed in the genus Phaenostictus that was erected in 1909 by the American ornithologist Robert Ridgway.[4] The genus name is derived from the Ancient Greek phainō meaning "to display" and stiktos for "spotted".[5] Ridgway considered that the species was related to the genus Phlegopsis (the bare-eyes) but that it differed in having a longer tail, rounded nostrils and a few other characters.[4]
Molecular phylogenetic studies of the antbird family, Thamnophilidae, have found that the ocellated antbird sits in the tribe Pithyini and its closest relatives are found in the genus Pithys.[6]
Three subspecies have been described:[7]
The ocellated antbird is a medium-sized antbird, measuring 19 to 19.5 cm (7.5–7.7 in)[7] and weighing 44–58 g (1.6–2.0 oz). Females tend to be slightly smaller than males and weigh slightly less.[8] The plumage and bare parts of the male and female are the same. The eye is surrounded by a large bare blue patch of skin. The head and throat is black with a grey crown and a rufous nape. The upperparts and wing coverts are olive brown with black spots. The rest of the feathers of the wing are black edged with olive. The breast is rufous and belly is olive brown, both have large black spots. The bill is large and black. Juvenile birds have a darker crown, the rufous areas are brighter and the spots are reduced or absent.[7] The species conforms with Bergmann's rule, with birds closer to the Equator having smaller wings and bills than those further away.[8]
The ocellated antbird ranges from Honduras to Ecuador. The race saturatus is found from northern and eastern Honduras through eastern Nicaragua, eastern and northern Costa Rica into the west of Panama. The nominate race is found in the rest of Panama and the Pacific slope as the Andean slope of western Colombia. The race pacificus is found in the extreme south of coastal Colombia and northwestern Ecuador.[7]
The ocellated antbird is a rainforest bird, being found in lowland and hill primary rainforest, as well as secondary forest. Within this habitat it occupies the understory of the forest, feeding and living close to the forest floor. It is found from sea-level up to 1,200 m (3,900 ft) in Costa Rica, but only up as high as 900 m (3,000 ft) in Panama and Colombia and 700 m (2,300 ft) in Ecuador; it is more commonly found below 400 m (1,300 ft) in the later country.[7] They seldom enter or cross open areas, unless the ants that they are following do so.[9]
The ocellated antbird (Phaenostictus mcleannani) is a species of antbird in the family Thamnophilidae. It is monotypic within the genus Phaenostictus and is found in southern Central America and the northwestern part of South America. Its natural habitat is the understory of tropical moist lowland forest, foothill forest, and tall secondary growth woodlands.
The species is 19 cm long and weighs around 50 g. The eye is surrounded by a large area of bare blue coloured skin. The plumage varies slightly amongst the three subspecies, but overall it has a grey crown, black throat with a buff breast changing into a spotted belly and back.
The bird feeds primarily on insects, arthropods, and sometimes on small lizards. Most of its prey is obtained from trails of army ants, which flush the prey from hiding places. One such army ant species is Eciton burchellii. The ocellated antbird is considered an obligate follower of army ants, seldom foraging away from swarms. Amongst the species of antbirds and other army ant followers (such as tanagers and woodcreepers) it is usually a dominant species.
The social biology of this species is unusual for the antbird family. The breeding pair form the nucleus of a group or clan that includes their male offspring and their mates. These clans work together to defend territories against rivals. The open nest cup was only recently described, with a clutch of two eggs.
