Dear Tweeters,

Michael Price seems to have overreacted to my recent message, in
which I pointed out that the unusual Black-headed Grosbeak song
reported from Sea Island, near Vancouver, was highly aberrant, and
that the normal songs of the two species are very different and not
likely to be confused. Several points in his reply require rebuttal or
further discussion.
I did not "denigrate the skills" of the birders who reportedly
heard this unusual song. (Keep in mind, this was a second-hand report
by Michael, who did not hear the song himself and did not name the
observers.) The observers may have been experienced, or they may have
been neophytes. I have witnessed an inexperienced birder identify a
Spotted Towhee as a Black-headed Grosbeak. Even if the observers were
experienced, I remain somewhat skeptical of the claimed unusual song.
Such skepticism is quite appropriate in view of my own personal
experience of more than 40 years' birding, in which I have SEEN
hundreds of Black-headed Grosbeaks in the act of singing, and have
never heard one giving a chat-like or Mockingbird-like song. Even
experts can make mistakes (I still do so occasionally), and my
skepticism should not be taken as an insult to the (nameless)
observers. Rather, it should be a challenge to Michael and to others
to show the grosbeak with the weird song to other birders.
The situation is analogous to a report of a Painted Redstart in
B.C. (One really did show up in 1973.) If you can show the bird to
other birders, or take a photo of it, then you can expect to believed;
if not, then you should expect other birders to be skeptical. (I'm
from Missouri-- show me!) So far, there are not Records Committees to
document unusual songs or behaviour, as there are for unusual
occurrences, but maybe there should be. If you want to be believed,
get out that tape recorder!
To give Michael credit, I tried to point out in my previous post
that birds do sometimes sing aberrant songs (the Savannah Sparrow that
sang a Horned Lark song), and agreed with him that whatever else is
said, caution is needed in identifying birds by songs and calls.
However, once again, Michael has chosen to interpret my remarks as a
personal attack on others, which they were not. (I don't even know who
the observers were !)
Michael seems to have assumed that the grosbeak was "mimicking" a
Yellow-breasted Chat. He states that

"grosbeaks, like many of the finches, clearly [have] a capability for
mimicry.."

He is correct that many finches incorporate mimicry in their
song--but not just one species at a time. Of the finches I am familiar
with, Purple Finches, Cassin's Finches, Pine Siskins, and Lesser
Goldfinches (but not American Goldfinches, crossbills, or many other
finch species) use vocal mimicry. They incorporate call-notes of
several bird species, strung together in rapid-fire sequence in a
pattern which is different for each finch species, in such a way that
most observers cannot recognize the mimicry in these songs. They do
not mimic one species at a time, and especially not "in response to a
perceived territorial threat from an alien species...". Interspecific
territoriality is infrequent in songbirds, and when it does occur, is
usually between closely-related species (e.g. House Wren and Bewick's
Wren), not between species as different as Black-headed Grosbeak and
Yellow-breasted Chat.
Michael is in no position to be lecturing us on vocal mimicry, or
on identifying birds by song. In an earlier E-mail that he posted to
Tweeters on May 22, he admitted that

"it took me over ten northbound migrations before I didn't need to get
a visual confirmation on Vancouver BC's regular warbler species...and
I still don't have a 100% reliable grasp on the difference of songs
between unseen Hammond's Flycatcher... and Dusky Flycatcher".

As Michael notes, "most people's auditory memories are nowhere
near as good as their visual ones", and clearly he counts himself in
that group. It probably took me 2 springs, not 10, to learn my warbler
songs and calls, and I learned how to reliably discriminate Hammond's
from Dusky Flycatchers, by song or call, in 1964. (Admittedly, I still
have trouble telling some Junco songs from some Chipping Sparrow
songs, but then, I don't know anyone who doesn't.) I know lots of
birders who have a similar ability to discriminate songs and calls,
although many of us don't. Frankly, I would not put a lot of faith in
the results of those forest bird surveys that Michael conducted.

I would like to wind up with three conclusions:

(1) Caution is always advisable in identifying unseen birds by songs
or calls. We all need to recognize that, even among experienced
birders, ability to discriminate and remember songs varies greatly. We
each need to recognize our own limitations. No argument here.

(2) Black-headed Grosbeaks do not show much individual variation in
songs (compared to, let's say, Song Sparrows or Spotted Towhees). They
can be easily confused with American Robins or maybe Red-eyed Vireos,
but not with Yellow-breasted Chats, which sound dramatically
different.

(3) The oddball Black-headed Grosbeak song described by Michael needs
to be documented on tape, and the observers need to be able to show
this bird to others. Vancouver birders, take up the challenge! If they
can't find this bird again, then I will remain somewhat skeptical,
and, I suspect, so will most Tweeters. (Yes, I still find it hard to
believe Killdeer calling like Willets, although I've heard Starlings
give Willet imitations countless times.)

Sincerely,

Wayne Weber
114-525 Dalgleish Drive
Kamloops, B.C. V2C 6E4
Phone: (250) 377-8865
wayne_weber at bc.sympatico.ca




-----Original Message-----
From: Michael Price <mprice at mindlink.bc.ca>
To: tweeters at u.washington.edu <tweeters at u.washington.edu>
Date: Monday, June 14, 1999 1:25 AM
Subject: Re: Grosbeak/Chat Song Resemblance: A Fluke


>Hi Tweets,
>
>Wayne Weber writes:
>
>> The song described second-hand by Michael Price on June 11 as "a
>>series of mockingbird-like repeated notes"-- if the singer was
indeed
>>correctly identified as a Black-headed Grosbeak--
>
>Wayne's unsubtle denigration of their skills aside, the observers
were not
>mistaken in their identification of a species with which they're both
>familiar: to reiterate: they watched the grosbeak uttering a
>chat/mockingbird-like song for several minmutes before singing
elements of
>the more conventional BHGR song.
>
>>is a highly aberrant
>>one for that species.
>
>The aberrancy is more of an assumption than hard fact: both species
sing
>from cover much of the time, and grosbeaks, like many of the finches,
>clearly has a capability for mimicry which may be mistaken for other
species
>even by ornithologists, however skilled, who do not get a visual
>confirmation to their auditory ID. This may be a far more common
occurrence
>than we think, and in fact such mimicry might be a standard response
to a
>perceived territorial threat from an alien species in the same
habitat.
>
>Once, years ago, I was at the Iona settling ponds at a time when
there were
>several pairs of nesting Killdeers Charadrius vociferus and a single
vagrant
>Willet Catoptrophorus semipalmatus. Unusually (normally this
Vancouver
>vagrant species stays silent), the Willet began uttering its
>'prrrilll-illl-illit!' call. I nearly fell over when the Killdeers
all began
>loudly *mimicking* the Willet's call. For the next three or four
minutes,
>the settling ponds sounded like a bedlam of Willets. Then, when the
calls
>died away, the Willet started calling again, and again all the
Killdeers
>responded by echoing the call. I stress that it was a *perfect*
mimicry.
>This happened five or six times, then everyone seemed to lose
interest.
>
>Nobody I've talked to has ever had a similar experience, and when I
told
>Wayne about this in hope of getting some kind of explanation, he just
>laughed in my face and flatly refused to believe it had happened at
all (and
>presumably still doesn't), showing that aberrancy may be as much in
the mind
>of the beholder as in nature. Incidentally, years later, I *still*
haven't
>the faintest idea why (nesting) Killdeers would mimic Willets. Not a
clue.
>It may be something to do with Killdeer territoriality or
call-similarity or
>Willet predation on Killdeer chicks or the moon being in Capricorn. I
really
>don't know. But I do know that outright skepticism is usually less
fruitful
>than speculation about what mechanism might account for unusual
behavior in
>usual species. Such examples demonstrate that even common species can
often
>confound our certainties and mock our hubris.
>
>>The grosbeak's normal song, a series of rapid,
>>rich warbles, is easily confused by inexperienced (or
>>hearing-challenged) birders with that of an American Robin, a
Hepatic
>>Tanager, or perhaps even with a Red-eyed Vireo. However, it bears no
>>resemblance whatsoever to the normal song of a Yellow-breasted Chat.
>
>Stipulated.
>
>> Among thousands of Black-headed Grosbeaks that I have heard
>>singing over several decades, I have never heard one sing in the
>>manner described by Michael. (I acknowledge that Michael was not the
>>actual observer, and the description of the song may have lost a
>>little in the translation.)
>
>Well, ignoring Wayne's second, more subtle slur on the observational
>abilities of the birders who related this incident to me, or on my
ability
>to mediate the matter--I can't quite make out which-- I agree:
neither have
>I. But BHGR songs aren't quite as standardised as Wayne's remarks
imply:
>there is suffcient difference in intonation, cadence and quality to
make a
>blanket statement unwise. Some of these differences may be
age-related, or
>depend on nearness of fledging of the young or whether a bird is a
>sexually-prospecting or territory-less male or is incorporating
phrases of
>another species' song or some other factor. Individual birds in
migration or
>displaced by habitat destruction may sound different to the standard
song.
>Heck, even individuals in adjacent territories sound slightly
different to
>each other. Individuals at the extremes of BHGR songs are not only
going to
>sound different to each other but are also gojng to sound different
from the
>norm. All this is to say that one should expect a wider range of
variation
>in song-phrasing and -quality even in Black-headed Grosbeaks than one
would
>think at first encounter. And be prepared to be surprised from time
to time
>by more odd flukes than you'd expect.
>
>Michael Price
>Vancouver BC Canada
>mprice at mindlink.net
>