Black-eared Yellow Warbler
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For more information about native warblers, see this post.
Black-eared
Yellow Warbler, Cardellina
melanoauris L 10-12 cm, WS 14-16 cm, Family: Parulidae
IUCN Conservation Status: Least concern (LC)
Description:
Small,
active songbird with round body, large head, and long tail. Yellow overall,
with olive upperparts and bright yellow undersides, with whitish edging to the
wing and tail feathers. Males have a black, comma-shaped ear patch. Slender,
straight bill and large dark eyes, pinkish legs. Females similar, but duller,
more greenish overall, lacks black mark. Smallest and most plain of native
warblers.
Voice:
Song
is two-parted; first a high-pitched warble followed by a sharp buzzy trill. Song
usually lasts about two seconds, with each part even in length. The warble
starts of clear and sweet before dropping into the buzz, which is raspier. May
sing just the second part, the buzzy trill. A variety of calls include quick
chirps and buzzy chips, but the most common is a short, fast raspy chit.
Range and Habitat:
Summer
range encompasses the entirety of Novasola, including Kosatka and Francis
Islands, but less common in the interior steppe. Migrates to spend winter in California
and the southwestern US. Can be found in most ecosystem types with woody
vegetation like conifer, deciduous, and mixed forests, and shrublands, but are
heavily associated with wet areas like wetlands and riparian zones like streams
and riversides. Rarely found far from water bodies. They most often use willow,
aspen, alder, or cottonwood stands.
Discussion:
Bouncing
and dancing about the underbrush, Black-eared Yellow Warblers are always
moving. Their energetic and frantic movements often make them difficult to observe,
despite likely being the most abundant warbler on Novasola, but other cues
apart from their appearance help distinguish them from other endemic warblers. These
warblers are tied to wet habitats like streams and swamps, and often stay nearer
to the ground in the understory than other warblers, except Crescent Warblers. Their most distinctive
feature however is their song, clear at first before becoming a raspy buzz,
which echoes through wetlands and mountainsides across Novasola.
Black-eared
Yellow Warblers eat mostly insects and other invertebrates which they pick from
foliage like stems and the undersides of leaves. They may also hover or sally
to catch insects mid-air. Their preferred food sources include caterpillars, ants,
mayflies, beetles, flies, and bees, and they often forage low in the understory,
in shrubs and dense thickets of alder or willow.
Like
most native warblers, Black-eared Yellow Warblers winter off the island in
California, Arizona, and Nevada, but they breed on Novasola, arriving in mid-to-late
May and leaving in mid-August. When males arrive in the spring, they establish
territories, which they do mostly through song, which they also use to attract
mates. It is common to hear multiple neighboring males singing back and forth over
one another, but they will also defend their territories more aggressively. The
warblers form monogamous pairs during breeding, but often pair with new
individuals each breeding season and males often engage in extra-pair
copulation, which is to say they often breed with females other than their mate.
Females build nests on the ground in areas of dense vegetation and perform all the
incubation, but males will help feed chicks.
Despite
its relative abundance on Novasola, the Black-eared Yellow Warbler was never referenced
in writing until Reichwald’s observations during the NRC expeditions. This has
led some to theorize that this warbler was far less common in the past, but no
other data supports this, and tallies kept by Reichwald suggests they encountered
many of the warblers. Instead, it is more likely that no one recorded encounters
with this bird because of its similarity to other species or challenging ID, or
because their habitat preferences and behaviors make them difficult to observe.
“An
upside to this area is the abundance of birdlife. Perhaps of most interest to
me are the many warblers I have observed and heard during this hike, of at
least three varieties, all of which yellow. Having not yet gotten a good look
at any, I have relied so far only on song to differentiate them. I don’t know
whether this area is particularly dense with warblers when compared to other
stretches of the Fastwaters, as it seems, but I am hopeful I should get the
chance to study them in great detail.” – Expedition log, May 29, 1902
“It should seem to any observant explorer of the Novasolan territory that many
portions of this country are as saturated with water as they are with the
sounds of the Black-eared Warbler. Indeed they come hand-in-hand, as the areas
so beset by water, be them lowlands or gullies or coasts, are precisely those
favored by the warbler. Just as common in valley swamps as on windward mountain
slopes, the Black-eared Warbler accompanies wetlands across the island and
provide these parcels with their summer music.
…
Of
the ten years I have made the Fastwaters my home, nine went by without my
knowing anything of significance regarding the Black-eared Warbler’s nesting
behaviors. It was not six months ago I discovered my first nest, built into a
small depression in the Sphagnum at the base of a small willow, on a
return visit to Big Soggy Bog. The warblers were in great numbers here and not long
after this discovery I came across two more nests. In each instance the female was
displeased by my intrusion and both she and her mate elected to fend me off
with surprising tenacity.” – Native Birds of Novasola, 1912
“The
Black-eared Warbler is the most numerous of its kind around wetlands and
riversides. Though bright yellow like other warblers, compare its smaller size
and plainer plumage. The female removes even the distinction of the male’s dark
auricular spot. To find these warblers look low, as they are reluctant to
mingle in the flora above two meters, and totally unwilling above three.” – Manual
to Novasolan Birds, 1914