Species Of Antbirds Research Articles

Species richness of Antbirds (Thamnophilidae) in more central and peripheral sites of terra firme forest in the eastern edge of the Amazonia

Antbirds (Thamnophilidae) comprise many insectivorous, mostly understory birds present in all Neotropical biomas. Many species occur specifically in the Amazonia, so a decline in species richness is expected from central Amazonian sites, to peripheral ones; this pattern is due primarily to the evolutionary history of the taxon. Rapid surveys to state the antbird species richness were performed in six sites of terra firme forest in the Belém Center of Endemism, the Easternmost and one of the most threatened regions in the Amazonia. These sites followed a series from more central to more peripheral areas, the latter being located in the edge of the Amazonia. The antbird species richness of every site was stated by presence-absence criteria. Two surveys were made in each site, by walking three transects in each of two trails in every survey. This species richness progressively fell from 19 species in the most central site (Gurupi Biological Reserve) to only two in the most peripheral one (São Luís). Probably, the gradient in the species richness is primarily associated to the evolutionary history of this group, however new studies using methods appropriated to assess the effects of environmental degradation in the regional richness of Thamnophilidae and other forest bird species should be encouraged.

A new species of antbird (Passeriformes: Thamnophilidae) from the Cordillera Azul, San Martín, Peru

ABSTRACT We describe a distinctive new species of antbird (Passeriformes: Thamnophilidae) from humid montane forest (1,340–1,670 m above sea level) of the Cordillera Azul, San Martin Region, Peru. Plumage, voice, and molecular evidence distinguish this species from its sister taxon Myrmoderus ferrugineus (Ferruginous-backed Antbird), which is found in lowland Amazonian rainforests of the Guiana Shield and Madeira-Tapajos interfluvium. The new species is presently known only from one ridge in the Cordillera Azul, and therefore we recommend further fieldwork to better estimate its distribution and population size.

Interspecific information use by army-ant–following birds

ABSTRACT Many animals use cues from other species to gather information about foraging opportunities, but engaging in such behavior requires balancing the potential benefits with the risks of increased competition. Neotropical birds that follow army ants are an appropriate system within which to study such eavesdropping behavior. Mixed-species groups of these understory birds congregate around ant swarms, where they forage on insects flushed by the ants. Obligate ant-followers have specialized behaviors to track ant swarms and may serve as information sources for facultative ant-followers. Owing to strong dominance hierarchies among species, however, the value of the information likely depends on the competitive relationship between the information provider and the eavesdropper. I investigated whether ant-following birds preferentially followed the songs of some antbird species over others, testing the prediction that the vocalizations of small (subordinate) ant-following species would attract more indivi...

Territoriality of Six Thamnophilidae Species In A Cloud Forest In Southeastern Brazil

ABSTRACT Territorial systems of Neotropical birds remain poorly understood, especially considering the effect of interspecific interactions. Studies on territorial behavior provide information about demography and life history, and are useful for the refinement of conservation strategies. We assessed territories of six species of antbirds (Thamnophilidae) from August 2010 to May 2011 at Pedra Azul State Park, a protected area in southeastern Brazil, in a 30-ha sampling grid. Birds were captured, marked, and followed through the study area. Territory sizes of Plain Antvireo (Dysithamnus mentalis), Ferruginous Antbird (Drymophila ferruginea), Ochre-rumped Antbird (Drymophila ochropyga), White-bibbed Antbird (Myrmeciza loricata), White-shouldered Fire-eye (Pyriglena leucoptera), and Variable Antshrike (Thamnophilus caerulescens) were estimated by the convex polygon method. We found 46 territories of the six species. We compared and evaluated the effect of body size on territories among the species. Males and...

Thamnophilidae (antbird) molt strategies in a central Amazonian rainforest

ABSTRACT Avian molt, or the regularly scheduled replacement of feathers, is an important life history event, particularly in central Amazonian rainforest birds for which a relatively high proportion of the annual cycle can be dedicated to this process. Here, we detail molt strategies of 18 antbird species (Thamnophilidae) based on 2,362 individuals captured from lowland tropical rainforest at the Biological Dynamics of Forest Fragmentation Project near Manaus, Brazil. All species exhibited a molt strategy consistent with the Complex Basic Strategy, in which birds undergo an inserted preformative molt within the first cycle, but apparently lack prealternate molts. The preformative molt and resulting formative plumage aspect of the 18 antbird species can be grouped by three distinct patterns: 1) a complete molt resulting in an adult-like formative plumage without molt limits; 2) a partial molt involving body feathers, lesser coverts, at least some or all median and greater coverts, and sometimes tertials or...

Coccidial dispersion acrosstrans- andcis-Andean antbirds (Passeriformes: Thamnophilidae):Isospora sagittulae(Apicomplexa: Eimeriidae) from nonsympatric hosts

Isospora sagittulae McQuistion and Capparella, 1992 (Protozoa: Apicomplexa: Eimeriidae) is reported from White-throated Antbirds (Gymnopithys salvini (Berlepsch, 1901)) and from Common Scale-backed Antbirds (Willisornis poecilinotus (Cabanis, 1847)), which are thamnophilid birds from the Brazilian Amazon. Its oocysts are ovoidal to ellipsoidal, 28.4 μm × 22.4 μm, with smooth, bilayered wall, 1.1 μm. Micropyle and oocyst residuum are absent, but one to three polar granules are present. Sporocysts are subspherical to ovoidal, 15.0 μm × 12.6 μm. Stieda body thin and flattened and substieda body triangular to round. Sporocyst residuum composed of scattered granules. Sporozoites with refractile body and nucleus. This coccidium was originally described from the Spotted Antbird (Hylophylax naevioides (Lafresnaye, 1847)), a trans-Andean antbird that is not sympatric with G. salvini and W. poecilinotus, which are cis-Andean antbirds from lowland Amazon forest; therefore, this current study presents some assumptions to explain the dispersion of I. sagittulae among antbird species.

Multiple speciation across the Andes and throughout Amazonia: the case of the spot‐backed antbird species complex (Hylophylax naevius/Hylophylax naevioides)

AbstractAimTo investigate the role of historical processes in the evolution of the spot‐backed antbird species complex Hylophylax naevius/Hylophylax naevioides (Aves, Thamnophilidae).LocationThroughout the Amazon Basin and across the Andes in Central and northern South America.MethodsWe investigated the evolutionary history of the H. naevius/H. naevioides complex based on a total of 100 individuals from opposite banks of the major Amazonian rivers and both sides of the Andes. Nucleotide sequences from two mitochondrial DNA genes [1015 bp of cytochrome b (cyt b) and 1023 bp of NADH dehydrogenase subunit 2 (ND2)] and one nuclear marker [539 bp of intron 5 of the β‐fibrinogen (BF5)] were obtained. Phylogenetic relationships were inferred using Bayesian and maximum likelihood methods. We used Bayesian coalescent‐based approaches to evaluate demographic changes through time, and to estimate the timing of the diversification events.ResultsWell‐supported allopatric and parapatric lineages were recovered within the H. naevius/H. naevioides complex, with high levels of genetic differentiation, both on opposite sides of rivers (0.6–7.1%) and across the Andes (6.9%). Molecular dating and population demography suggest cladogenesis in various periods, associated with distinct vicariance and dispersal events.Main conclusionsOur data support the hypothesis that the uplift of the northern Andes and the consolidation of the modern Amazon drainage system were key to promoting the diversification of forest‐dwelling bird lineages in the northern Neotropics.

Eight anonymous nuclear loci for the squamate antbird (Myrmeciza squamosa), cross-amplifiable in other species of typical antbirds (Aves, Thamnophilidae)

Typical antbirds (~209 species) represent a diverse radiation of Neotropical birds that includes many species of conservation concern. Here we present eight anonymous nuclear loci designed for the squamate antbird Myrmeciza squamosa, a species endemic to the Atlantic Forest of Brazil. We also show that those anonymous nuclear loci are amplifiable in a number of other typical antbird species from related genera (Myrmeciza, Percnostola, Gymnocichla, Myrmoborus, Pyriglena and Formicivora), including three threatened species (Myrmeciza ruficauda, Formicivora littoralis, and Pyriglena atra). Those markers will be useful not only to help management of threatened species of typical antbirds, but also to explore their evolutionary histories, both at intra and interspecific levels.

Species loss, delayed numerical responses, and functional compensation in an antbird guild

When a community loses species through fragmentation, its total food consumption may drop. Compensatory responses of remaining species, whereby survivors assume roles of extinct competitors, may reduce the impact of species loss through numerical or functional responses. We measured compensatory responses in two remaining antbird species on Barro Colorado Island, Panama, four decades after the loss of their dominant competitor, the Ocellated Antbird, Phaenostictus mcleannani. We compared current abundances and behavior of these two species on Barro Colorado to those reported before the island lost Ocellated Antbirds, and to those in a nearby mainland population where all three species still exist as a space-for-time substitution. The smaller, more subordinate Spotted Antbird, Hylophylax naevioides, responded far more strongly than the larger Bicolored Antbird, Gymnopithys leucaspis, which is functionally more like the Ocellated Antbird. Islandwide density of Spotted Antbirds has more than doubled since the loss of Ocellated Antbirds. Moreover, Spotted Antbirds now spend so much more of their time following ant swarms that their metabolic biomass at these swarms has more than tripled since Ocellated Antbirds disappeared. These responses in Spotted Antbirds were apparently delayed by >20 years. Bicolored Antbirds have not increased substantially in islandwide density or metabolic biomass at ant swarms. We hypothesize that behavioral flexibility, as shown by Spotted Antbirds on Barro Colorado Island, is a major factor governing the extent to which fragmented ecosystems can buffer the impacts of species loss.

Species loss, delayed numerical responses, and functional compensation in an antbird guild

When a community loses species through fragmentation, its total food consumption may drop. Compensatory responses of remaining species, whereby survivors assume roles of extinct competitors, may reduce the impact of species loss through numerical or functional responses. We measured compensatory responses in two remaining antbird species on Barro Colorado Island, Panama, four decades after the loss of their dominant competitor, the Ocellated Antbird, Phaenostictus mcleannani. We compared current abundances and behavior of these two species on Barro Colorado to those reported before the island lost Ocellated Antbirds, and to those in a nearby mainland population where all three species still exist as a space-for-time substitution. The smaller, more subordinate Spotted Antbird, Hylophylax naevioides, responded far more strongly than the larger Bicolored Antbird, Gymnopithys leucaspis, which is functionally more like the Ocellated Antbird. Islandwide density of Spotted Antbirds has more than doubled since the loss of Ocellated Antbirds. Moreover, Spotted Antbirds now spend so much more of their time following ant swarms that their metabolic biomass at these swarms has more than tripled since Ocellated Antbirds disappeared. These responses in Spotted Antbirds were apparently delayed by >20 years. Bicolored Antbirds have not increased substantially in islandwide density or metabolic biomass at ant swarms. We hypothesize that behavioral flexibility, as shown by Spotted Antbirds on Barro Colorado Island, is a major factor governing the extent to which fragmented ecosystems can buffer the impacts of species loss.

Habitat and Life History Determinants of Antbird Occurrence in Variable‐Sized Amazonian Forest Fragments

ABSTRACTThe highest avian species richness on Earth is found in the Neotropics, with the speciose antbird superfamily (Thamnophilidae, Formicariidae, Grallariidae and Conopophagidae) accounting for 15 percent of South American passerine diversity. Antbird species have divergent life histories and ecological requirements, resulting in considerable interspecific variation in responses to anthropogenic habitat modification. Here, we examine interspecific differences in antbird responses to both habitat fragmentation and perturbation in a region of the so‐called ‘Arc of Deforestation’ of southern Brazilian Amazonia in northern Mato Grosso. We surveyed the antbird community of 31 variable‐sized forest patches and found that antbird species richness was predominantly affected by patch size and isolation, although forest patch quality was also important. Life history predictors were less important overall in determining patch occupancy and minimum patch area requirements with body mass and geographic range size the most important predictors. Foraging niche was also important; mixed flock followers, bamboo specialists and army‐ant followers were all more prone to local extinction in small fragments. Although most Amazonian antbird species are not currently threatened, rates of interfluvial endemism are high and future forest loss may imperil many species currently considered to be of low conservation concern. Lessons learnt in the identification of fragmentation‐sensitive genera and guilds may be applicable to other antbird species outside Amazonia, such as those in the Brazilian Atlantic Forest. Ensuring future survival of antbirds across neotropical forest landscapes that retain only a small percentage of their original primary forest cover will rest on protecting remaining large forest patches and maintaining structural and functional connectivity between them.

A phylogenetic approach to disentangling the role of competition and habitat filtering in community assembly of Neotropical forest birds

1. Methods that assess patterns of phylogenetic relatedness, as well as character distribution and evolution, allow one to infer the ecological processes involved in community assembly. Assuming niche conservatism, assemblages should shift from phylogenetic clustering to evenness with decreasing geographic scale because the relative importance of mechanisms that shape assemblages is hypothesized to be scale-dependent. Whereas habitat filtering is more likely to act at regional scales because of increased habitat heterogeneity that allows sorting of ecologically similar species in contrasting environments, competition is more likely to act at local scales because low habitat heterogeneity provides few opportunities for niche partitioning. 2. We used species lists to assess assemblage composition, data on ecologically-relevant traits, and a molecular phylogeny, to examine the phylogenetic structure of antbird (Thamnophilidae) assemblages at three different geographical scales: regional (ecoregions), intermediate (100-ha plots) and local (mixed-flocks). In addition, we used patterns of phylogenetic beta diversity and beta diversity to separate the factors that structure antbird assemblages at regional scales. 3. Contrary to previous findings, we found a shift from phylogenetic evenness to clustering with decreasing geographical scale. We argue that this does not reject the hypothesis that habitat filtering is the predominant force in regional community assembly, because analyses of trait evolution and structure indicated a lack of niche conservatism in antbirds. 4. In some cases, phylogenetic evenness at regional scales can be an effect of historical biogeographic processes instead of niche-based processes. However, regional patterns of beta diversity and phylogenetic beta diversity suggested that phylogenetic structure in our study cannot be explained by the history of speciation and dispersal of antbirds, further supporting the habitat-filtering hypothesis. 5. Our analyses suggested that competitive interactions might not play an important role locally, which would provide a plausible explanation for the high alpha diversity of antbirds in Amazonia. 6. Finally, we emphasize the importance of including trait information in studies of phylogenetic community structure to adequately assess the mechanisms that determine species co-existence.

Character displacement from the receiver's perspective: species and mate recognition despite convergent signals in suboscine birds

Many social animals use long-distance signals to attract mates and defend territories. They face the twin challenges of discriminating between species to identify conspecific mates, and between individuals to recognize collaborators and competitors. It is therefore often assumed that long-distance signals are under strong selection for species-specificity and individual distinctiveness, and that this will drive character displacement when closely related species meet, particularly in noisy environments. However, the occurrence of signal stereotypy and convergence in rainforest species seems to contradict these ideas, and raises the question of whether receivers in these systems can recognize species or individuals by long-distance signals alone. Here, we test for acoustically mediated recognition in two sympatric antbird species that are known to have convergent songs. We show that male songs are stereotyped yet individually distinctive, and we use playback experiments to demonstrate that females can discriminate not only between conspecific and heterospecific males, but between mates and strangers. These findings provide clear evidence that stereotypy and convergence in male signals can be accommodated by fine tuning of perceptual abilities in female receivers, suggesting that the evolutionary forces driving divergent character displacement in animal signals are weaker than is typically assumed.

Adaptive sensor arrays for acoustic monitoring of bird behavior and diversity: preliminary results on source identification using support vector machines

This article summarizes the work in our laboratories toward developing adaptive sensor arrays for monitoring bird vocalizations. We have focused on four species of antbird in a tropical rainforest in Mexico. Preliminary results of individual identifications using support vector machines are presented. We also describe our initial attempts at higher-order processing of information about the identification and localization of each source.

Automated species recognition of antbirds in a Mexican rainforest using hidden Markov models

Behavioral and ecological studies would benefit from the ability to automatically identify species from acoustic recordings. The work presented in this article explores the ability of hidden Markov models to distinguish songs from five species of antbirds that share the same territory in a rainforest environment in Mexico. When only clean recordings were used, species recognition was nearly perfect, 99.5%. With noisy recordings, performance was lower but generally exceeding 90%. Besides the quality of the recordings, performance has been found to be heavily influenced by a multitude of factors, such as the size of the training set, the feature extraction method used, and number of states in the Markov model. In general, training with noisier data also improved recognition in test recordings, because of an increased ability to generalize. Considerations for improving performance, including beamforming with sensor arrays and design of preprocessing methods particularly suited for bird songs, are discussed. Combining sensor network technology with effective event detection and species identification algorithms will enable observation of species interactions at a spatial and temporal resolution that is simply impossible with current tools. Analysis of animal behavior through real-time tracking of individuals and recording of large amounts of data with embedded devices in remote locations is thus a realistic goal.

ECOLOGICAL ADAPTATION AND SPECIES RECOGNITION DRIVES VOCAL EVOLUTION IN NEOTROPICAL SUBOSCINE BIRDS

Given that evolutionary divergence in mating signals leads to reproductive isolation in numerous animal taxa, understanding what drives signal divergence is fundamental to our understanding of speciation. Mating signals are thought to diverge via several processes, including (1) as a by-product of morphological adaptation, (2) through direct adaptation to the signaling environment, or (3) to facilitate species recognition. According to the first two hypotheses, birdsongs diversify in different foraging niches and habitats as a product of selection for optimal morphology and efficient sound transmission, respectively. According to the third hypothesis, they diversify as a result of selection against maladaptive hybridization. In this study I test all three hypotheses by examining the influence of morphology, acoustic environment, and the presence of closely related congeners on song structure in 163 species of antbird (Thamnophilidae). Unlike oscine passerines, these Neotropical suboscines make ideal subjects because they develop their songs without learning. In other words, patterns of vocal divergence are not complicated by cultural evolution. In support of the morphological adaptation hypothesis, body mass correlates with the acoustic frequency of songs, and bill size with temporal patterning. These relationships were robust, even when controlling for phylogenetic inertia using independent contrasts, suggesting that there has been correlated evolution between morphological and acoustic traits. The results also support the acoustic adaptation hypothesis: birds which habitually sing in the understory and canopy produce higher-pitched songs than those that sing in the midstory, suggesting that song structure is related to the sound transmission properties of different habitat strata. Finally, the songs of sympatric pairs of closely related species are more divergent than those of allopatric pairs, as predicted by the species recognition hypothesis. To my knowledge, these data provide the first direct evidence that species recognition and ecological adaptation operate in tandem, and that the interplay between these factors drives the evolution of mating signals in suboscine birds.

ECOLOGICAL ADAPTATION AND SPECIES RECOGNITION DRIVES VOCAL EVOLUTION IN NEOTROPICAL SUBOSCINE BIRDS

Given that evolutionary divergence in mating signals leads to reproductive isolation in numerous animal taxa, understanding what drives signal divergence is fundamental to our understanding of speciation. Mating signals are thought to diverge via several processes, including (1) as a by-product of morphological adaptation, (2) through direct adaptation to the signaling environment, or (3) to facilitate species recognition. According to the first two hypotheses, birdsongs diversify in different foraging niches and habitats as a product of selection for optimal morphology and efficient sound transmission, respectively. According to the third hypothesis, they diversify as a result of selection against maladaptive hybridization. In this study I test all three hypotheses by examining the influence of morphology, acoustic environment, and the presence of closely related congeners on song structure in 163 species of antbird (Thamnophilidae). Unlike oscine passerines, these Neotropical suboscines make ideal subjects because they develop their songs without learning. In other words, patterns of vocal divergence are not complicated by cultural evolution. In support of the morphological adaptation hypothesis, body mass correlates with the acoustic frequency of songs, and bill size with temporal patterning. These relationships were robust, even when controlling for phylogenetic inertia using independent contrasts, suggesting that there has been correlated evolution between morphological and acoustic traits. The results also support the acoustic adaptation hypothesis: birds which habitually sing in the understory and canopy produce higher-pitched songs than those that sing in the midstory, suggesting that song structure is related to the sound transmission properties of different habitat strata. Finally, the songs of sympatric pairs of closely related species are more divergent than those of allopatric pairs, as predicted by the species recognition hypothesis. To my knowledge, these data provide the first direct evidence that species recognition and ecological adaptation operate in tandem, and that the interplay between these factors drives the evolution of mating signals in suboscine birds.

Differential degradation of antbird songs in a neotropical rainforest: adaptation to perch height?

Habitat characteristics that affect transmission and degradation of acoustical signals should influence strongly the evolution of bird songs. In this study propagation properties of songs of five antbird species were measured in a rainforest in southern Venezuela. The investigated species (Myrmothera campanisona, Thamnophilus aethiops, Thamnophilus amazonicus, Myrmotherula axillaris, and Herpsilochmus dorsimaculatus) use different song post heights at all levels of the rainforest. Because there is a height-specific pattern in degradation, it is hypothesized that their songs are adapted to species-specific transmission paths. To test this assumption, transmission parameters (excess attenuation, signal-to-noise ratio, and blur ratio) were measured for the songs at five different heights and at three different distances. In three of the five species, the results indicate a strong influence of environmental conditions on the design of the vocalizations. Degradation was minimized by the concentration of the signal to a narrower frequency range, the usage of lower frequencies, or a slower time structure for the songs near the ground. The results are discussed in relation to acoustical models of sound propagation and physiology, and it is suggested that height-dependent degradation within a forest is an important selection pressure for transmissibility in avian communication.

NESTING RECORDS OF FIVE ANTBIRD SPECIES FROM THE COLOMBIAN AMAZON

Few nests of Amazonian antbirds (Thamnophilidae and Formicariidae) have been described. Here we present nesting records for five species of antbirds found in Tinigua National Park, Colombia. A pouch-shaped pensile nest of the Warbling Antbird (Hypocnemis cantator) in a treefall gap within seasonally flooded forest contained two eggs colored like those found in French Guiana but different from those in Amazonian Brazil and Peru. The Black-spotted Bare-eye (Phlegopsis nigromaculata) also nested in seasonally flooded forest; it constructed a cup-shaped nest inside a hollow rotten stump and laid two eggs. Two naked nestlings with bright yellow bills disappeared soon after hatching. Two cup-shaped nests of the Scale-backed Antbird (Hylophylax poecilinota) were in mature terra firme forest. Both contained two eggs similar in color to those of other subspecies; nestlings were naked and had conspicuous yellow bills. Those found in one nest disappeared 11 days after hatching. A nest of the Amazonian Streaked-Antwren (Myrmotherula multostriata) containing one egg was in seasonally flooded forest close to the river bank. This egg differed in coloration from others found in Brazil and from those of other members of the M. surinamensis complex, with which it was formerly considered conspecific. A Striated Antthrush (Chamaeza nobilis) nested in an unlined natural cavity some 3 m above the ground. The nestling closely resembled the adult but was smaller, had yellow bill commissures, and a shorter tail.

ANTBIRD GUILDS IN THE LOWLAND CARIBBEAN RAINFOREST OF SOUTHEAST NICARAGUA

Abstract Some 20 species of antbirds occur in lowland Caribbean rainforest in southeast Nicaragua where they form five distinct guilds on the basis of habitat preferences, foraging ecology, and foraging behavior. Three guilds are habitat-based, in Edge, Forest, and Gaps within forest; two are behaviorally distinct, with species of army ant followers and those foraging within mixed-species flocks. The guilds each contain 3–6 antbird species. Within guilds, species are segregated by body size differences between member species, and in several guilds are evenly spaced on a logarithmic scale of body mass. Among guilds, the factors by which adjacent body sizes differ vary between 1.25 and 1.75. Body size differences may be related to differences in preferred prey sizes, but are influenced also by the density of the vegetation in which each species customarily forages. Resumen. Unas 20 especies de aves hormigueras viven en el bosque tropical perennifolio, sureste de Nicaragua, donde se forman cinquo gremios dis...