Yellow Emeraldine
For more information about emeraldines, see this post.
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Yellow
Emeraldine, Barbalaetus aurus L 20-21 cm, WS 30 cm, Family:
Barbalaetidae
IUCN Conservation Status: Near threatened (NT)
Description:
Medium
sized songbird with long tail and plump body and strong legs. Yellow-brown
upperparts, with slate gray wings and tail, and lighter gray undersides. Slight
whitish edging on wing feathers. Distinctive bright iridescent “beard” of
throat feathers, unique to the emeraldine group, present only in males. Beard
yellow-green, lighter than other emeraldines. Females lack green beard,
undersides faintly streaked, juveniles like females but juvenile males will
grow beard in patches. Best distinguished by yellowish beard in males and lack
of any other field marks.
Voice:
Song
is a series of two buzzy trills raising in pitch followed by a third, shorter
descending trill. Most common call is a short, sharp tik. Males have a
“dance call” given only during courtship which is a short rattle. Females have
a soft peep call given only during courtship and incubation.
Range and Habitat:
Uncommon
bird, range extends across Novasola’s interior steppe. Can rarely be seen in
the Twin River valley. Prefers open grassland and meadow ecosystems with dense
understory. Will also use chaparral, oak scrub, and wetlands. Avoids altitudes
higher than about 7,000 ft and areas without thick understory.
Discussion:
Generally
uncommon, the Yellow Emeraldine is the rarest member of the emeraldine family, Barbalaetidae,
with the lowest population numbers. Thus, they are the least understood of
emeraldines. Richard Reichwald was the first person to describe them
scientifically, but even he only encountered a small handful in his lifetime. The
species name aurum is Latin for “gold”.
Like
all members of the family the Yellow can be difficult to observe due to their
preference for dense undergrowth, though they are found in less woody areas and
prefer more open prairie than other emeraldines, especially when compared to the
Farr’s which shares most of its range. Usually hidden in the grass, and their
coloration camouflages them quite well, they are most easily observed during
the spring when males sing to attract mates and defend territories.
In
the summer months, Yellow Emeraldines eat invertebrates like beetles, crickets, grasshoppers,
flies, and moths, as well as seeds. In the winter their diets consist almost entirely
of seeds and grains. Like other emeraldines they are mostly ground foragers and
will hop along the ground rummaging through leaf litter and detritus.
Emeraldines
are perhaps best known for their courtship displays and breeding behaviors. In
the spring, males will find a well-lit exposed branch, reed, or grass stem from
which they sing to attract females. Before singing, males will clear the ground
around the perch of any leaves, twigs, or other grasses so that only dirt,
moss, or needles are present. Once a female has flown in, she will perch above
the male so that she faces down at him toward the ground and he holds himself
almost upside-down and in direct sunlight. The male then flairs his beard and
moves his head from side to size, making rattling sounds. The Yellow Emeraldine dance is fast paced, with the male making many sudden and quick movements back
and forth. If the female is impressed with the dance, the two mate and find a
nest location. Both females and males help build the nest and rear young. Yellow
Emeraldines are the only member of the genus to build their nest structures
entirely out of grasses and non-woody vegetation. They find a densely vegetated
area of tall grasses, reeds, or sedges and begin to bend the stems downward,
weaving them together to form a dome structure. They add more and more leaves
and stems until the dome is woven tight. These structures are usually no taller
than six inches, but some have been recorded at a foot tall. The grass dome is
distinctive, and, though rarer, often easier to find than other emeraldine nests, as they are built in more open areas. Because the nests are made of
non-woody plants, Yellow Emeraldine structures do not usually last as long as
other barbalaetid structures. This, coupled with the Yellow’s more nomadic
behavior, means most Yellow Emeraldines build a new nest each year. Younger pairs,
or pairs struggling to find new territory, will use nests built by other
emeraldines if they find any remaining standing from previous years.
Despite
being a well-known feature of Novasola’s prairie and scrubland interior, the Yellow
Emeraldine is the least common of its family, though still relatively numerous
in its range. Reichwald encountered only four birds during the NRC expeditions,
and had to specifically go out searching for more of them in order to write
about them in Native Birds.
“On
my morning hike today I was graced with the fortune of having found a nest,
unknown to me, amid a sea of silver-grass. A circular half-dome of woven
fibers, many of which were grasses still attached by the roots to the ground,
bent into form. Though the builders were nowhere to be seen, it was evident
immediately by the manner and skill of the construction that this must by the
work of a Emerald bird. This structure was made in different form, and with
different materials, than the nests I am familiar with and it was placed out in
open country, shielded from view by only the silver-grass. Having witnessed the
effect of these nests on the other men of the Corps, I have decided not to tell
any of the party about this find or its location, in order I might return for a
few days without rushing to a new camp in a frightened hurry.” – Expedition
log, June 11, 1902
“The
Yellow Emeraldine, golden as the dawn sunlight on the prairie it calls home,
shines in the memory of any blessed to have witnessed it. Native to the
island’s interior it can be found, with some persistence, in the grasses and
shrubs of more arid country.
…
The
Emeraldine is a secretive one, confident enough to reveal its location by way of
song but not enough to show itself. Indeed the most reliable way for an outdoorsman
to spot the bird is to follow the songs until you are almost upon it, for then
the bird will take flight and in a hurried manner land again nearby, to be swallowed
by the herbage. In such a manner may one follow the bird, step by step, to its
nesting location.” – Native Birds of Novasola, 1912
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| Yellow Emeraldines are unique for building their domed nest structures entirely out of grass and leaves. Illustration provided by the Museum of Novasola. |