The Yellow-rumped Warbler
By Tait Johansson
 Many
birders find identifying fall warblers to be a tricky proposition. One good
species to start with is the Yellow-rumped Warbler (Dendroica coronata)
since it is probably the most common fall warbler in our area.
The most consistently distinctive feature of this species’ appearance is, as its
name suggests, its yellow rump patch. This patch is present in all plumages
except in the juvenile plumage, which is held only from about May to August,
mostly on the breeding grounds to our north. The rest of the bird’s upperparts
are mostly brown to gray, with most fall birds tending to be brownish. The bird
has fine, dark streaks over the background color going down the back. The wings
and tail are grayer than the rest of the upperparts, and there are two white
wingbars. The head is brown to gray, and grayer birds have a dark to black
auricular (ear) patch. It has a broken white eyering, interrupting a white to
whitish eyeline. (The eyeline is not present on duller-plumaged birds.) The
Yellow-rump’s underparts are white to pale tan, the throat being the lightest.
It has heavy to light dark streaking from the breast down to the sides where the
streaking is the heaviest. The sides also sport a small yellow patch, visible on
all but the dullest birds. Two small white patches at the corners of the upper
surface of the tail are visible in flight.
In the spring and summer, the song is a high, loose, warbling trill, whereas the
usual vocalizations we hear in the fall are a clipped “check” call note and a
high-pitched, ascending “sweet” flight note, especially familiar sounds along
the coast in October, when the species can be impressively abundant.
Though insects make up most of its diet in summer, this species is unique among
warblers in its ability to subsist almost wholly on fruit, especially
bayberries, which hold high concentrations of energy-giving lipids (fats). This
adaptation allows the Yellow-rumped Warbler to winter much farther north than
our other warblers, being regularly found in winter as far north as Nova Scotia.
In the more northern parts of its winter range, the Yellow-rumped Warbler is
usually found close to the coast, almost inevitably near stands of Northern
Bayberry (Morella pensylvanica). The
fruits of Poison Ivy (Rhus toxicodendron) and Eastern Red Cedar (Juniperus
virginiana) are also sometimes part of its diet.
In summer, the species frequents conifer woods mostly in boreal forests from
Alaska to the Maritimes. In the Northeast its breeding range extends south to
central New England and New York. In the south, it also breeds at high
elevations in the Appalachians to West Virginia. Most of the time when we see
yellow-rumps in our area, they are in transit between their breeding and
wintering grounds. During this time, they can be found in almost any habitat,
from forests to fields, foraging for insects and berries.
Photo Courtesy of and Copyright ©
Richard L. Becker
www.songstar.org
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