Seeing is believing when identifying (patiently!) an Audubon’s vs. Myrtle
Yellow-Rumped Warbler.
But
sometimes you only hear an obvious Yellow-rumped Warbler chip note.
At
least I do.
Then,
the Mind Game is to ask myself: Is that an Audubon’s or Myrtle subspecies
within the species of Yellow-rumped?
Difficult
decision (!)
And
consider your antenna first-rate, premium, high-octane — if you can tell the
difference between these two call notes and confidently exclaim: “That’s an
Audubon’s” (Or “Eureka, trust me: that’s a Myrtle chip note.”
(Above: An Audubon's Yellow-rumped Warbler subspecies (in breeding plumage) appears in the top photo. A non-breeding view of a Myrtle Yellow-rumped Warbler subspecies is below the Audubons'.)
*
Why
do you need to tell one chip note vs. the other to know if it’s an Audubon’s
vs. a Myrtle?
Because,
of course, most Yellow-rumpeds are NOT singing during the non-breeding season,
but you do often hear their loud chip or call notes from October – April when
they’re in my area (San Francisco Bay Area where I am a Birding Guide in Marin
County).
In many cases you can hear how the Myrtle (one of the subspecies of the
Yellow-rumped Warbler species) has a flatter and softer chip note than the Audubon’s.
The “ch” component of the call note is weaker for the Myrtle and it often gives
many calls in rapid succession.
However, be careful. Intergrades (individuals that display visual
characteristics specific to both Audubon’s and Myrtle) may announce call notes
of the other subspecies. In other words, it’s possible to see a bird that looks
like an Audubon’s, but it’s call note sounds like a Myrtle. This individual
could likely be an intergrade.
Of
course, once you hear a Yellow-rumped chip note, go find it.
Then
you can truly tell the difference in the two subspecies by their appearance: In
general, the Myrtle male is told by its white throat that wraps farther around
toward the back of the head/nape....while the Audubon’s male has a yellow
throat. Note the Myrtle often also displays a slight white supercilium or
eyebrow at the front of the head, whereas the Audubon’s head is plain and gray
throughout.
My
web site for warbler questions, warbler information, warbler quizzes: http://warblerwatch.blogspot.com
My
bird guiding in California and birding tours in California information:
warblerwatch.com via the Birding Tours button at the home page.
