The Black- fronted Nunbird (Monasa nigrifrons;
plate 15- 72) ranges throughout the Amazon Basin.
This ubiquitous, robin- size, forest- dwelling bird is
often revealed by its bright red bill as it perches on an
understory branch. Nunbirds will form noisy groups
and typically join large mixed- species foraging flocks.
Some nunbird species follow army ant swarms.
Puffbirds (plates 15- 73– 77), which feed like
nunbirds, are large- headed, heavy- bodied birds so
named for the puffed appearance of their feathers.
Though some species are boldly patterned in black
and white, most species, particularly those that inhabit
shaded understory, are brownish or tan. Their cryptic
plumage plus their stationary behavior when perched
in the shaded forest understory makes them easy to
overlook. Like flycatchers (chapter 8), puffbirds have
large bills with prominent rictal bristles (hairlike
feathers around the base of the bill; plate 15- 73) that
probably aid in capturing aerial insects).
Nunbirds and puffbirds excavate nests in termite
mounds or in the ground, depending upon species.
Rather little is known about the details of their breeding
biology, but they do form strong pair bonds, and many
species are commonly observed in pairs.Wrens
There are 85 species of wrens in the world and 84 of
them are found only in the New World. Wrens (family
Troglodytidae) obviously evolved in the New World
and they have an impressive diversity, occurring in
all major terrestrial habitats other than arctic tundra.
Wrens include the familiar House Wren (Troglodytes
aedon; plate 15- 78), the most broadly distributed
species of wren in the Americas, ranging from Canada
to southern Chile and Argentina.
Wrens are fundamentally insectivorous and many
species are skulkers, remaining in the well- shaded
forest understory, a challenge to observe.
Wrens are well known for their remarkable ability
to sing highly complex songs. There are 48 wren
species in South America, and several among them
are simply amazing singers. One of those is the well-
named Musician Wren (Cyphorhinus arada; plate 15-
79). Often part of mixed- species flocks and always in
the understory, the Musician Wren will spontaneously
begin to sing its complex song, which seems to oscillate
in pitch. You just have to hear it (which you can do on
YouTube).Plate 15- 78. The House Wren is a common bird around houses
and gardens throughout its extensive range. This one was in a
hotel garden in Panama. Photo by John Kricher.Plate 15- 79. Though rather nondescript in plumage, the
Musician Wren is anything but dull in its singing ability. This
one is upright and singing; it is difficult to get such a clear look
as this. Photo by Andrew Whittaker.Plate 15- 80. The songs of the White- breasted Wood- Wren and
other similar wren species are among the most often heard
sounds in Neotropical rain forests. Photo by Dennis Paulson.chapter 15 neotropical birds: the bustling crowd 291