“antbirds.” All antbirds were once placed in the family
Formicariidae, but analysis of DNA patterns in the
group resulted in the splitting of the family. About 75%
of the antbird species are placed in Thamnophilidae,
referred to as typical antbirds, while the other 25% are in
either the antthrushes (Formicariidae) or the antpittas
(Grallariidae). Antbirds reach their peak species
richness in Amazonia, where up to 30 or 40 species
may occur together. The name antbird, or formicariid,
comes from the army- ant- following behavior of some
species. However, most antbirds do not follow army
ant swarms. Some never do, some occasionally do, and
some virtually always do. This latter group, comprises
both typical antbird species and antthrushes (plate 15-
111).
Thamnophilid antbirds are more boldly patterned
than ovenbirds, and many are sexually dimorphic.
Males are often black and white. Some, like the
widely distributed and common Barred Antshrike
(Thamnophilus doliatus; plate 15- 112), are zebra-
striped. Others are grayish black with varying amounts
of white patterning on wings, breast, and flanks. Still
others are chestnut or brown. Females tend to be rich
brown, tan, or chestnut. Some antbirds have an area
of bare blue or red skin around the eye, and in some
species the iris is bright red (plate 15- 113).
Most antbirds are foliage gleaners, picking and
snatching arthropods from foliage, and some capture
insects on the wing. They forage at all levels, from the
canopy to the litter on the forest floor, and various
antbird species tend to feed at specific heights above
the forest floor. Antbirds typically form mixed- species
flocks with other birds. Mixed flocks of up to 50 bird
species move through Amazonian lowland forests,
of which 20 to 30 species may be antbirds. Certain
species, such as the fly- catching antshrikes (genus
Thamnomanes), occupy the role of central species in
the flock. These antshrikes are highly vocal and act
as sentinels, warning the others of impending danger
should they spot a forest- falcon or other potential
predator.
There are about 30 species of professional ant-
following birds, each of which makes its livelihood by
capturing arthropods scattered by advancing fronts of
army ants (chapter 10). In addition, other bird species
frequently, but not always, can be found accompanying
the ants. The Spotted Antbird (Hylophylax naevioides),
the Bicolored Antbird (Gymnopithys bicolor; plate 15-
114), and the Black- faced Antthrush (discussed below)Plate 15- 111. The 19 cm (7.5 in) Rufous- breasted Antthrush
(Formicarius rufipectus) is occasionally found at ant swarms,
but it is not a “professional” ant- follower. It is a lower montane
species found along the Andes from Venezuela to Peru. Photo
by Edison Buenaño.Plate 15- 112. Male Barred Antshrike. (Thamnophilus doliatus)
Photo by Kevin Zimmer.Plate 15- 113. This is an unusually good view of the Great
Antshrike (Taraba major), one of the larger and most widely
distributed of the antshrikes. It is normally a skulker and is
more often heard than seen. This bird is a male. Females are
brown where the male is black. Photo by John Kricher.chapter 15 neotropical birds: the bustling crowd 301