Hi,
I have cc's this to the naturerecordist mailing list to see if people like
Kevin Colvar, Lang Elliott, and John Neville have any comments.
I hear a whole range of vocalizations for Blackpoll Warblers here in
Alberta, Canada. They vary quite a bit in pitch and speed of delivery.
Some sound like Kevin Colvars bird from Alaska, some sound like the slower
bird on Lang Elliotts Stokes Eastern Guide. They also vary some in pitch -
some birds singing considerably higher than others. The first time I
encountered the fast song I did not know what it was because I had learned
the slower song from an old LP. It sounded like an insect and not a bird to
me.
I only have about 5 Blackpoll recordings dug out of the mass of 90 tapes we
have recorded. Checked Kevin's recording against one of mine and my fastest
is only about 30 percent slower. I have heard the very fast songs in the
Swan Hills (under the B in the word Alberta on the map in the back of
Sibley) and in Cottonwood Slough at Jasper National Park (about at the O in
Rocky Mountains on the same map) which were during breeding season for sure
(second to third week in June). I have heard fast and slow vocalizations
in early June at Cold Lake (near the Saskatchewan border (about at the R in
Great Plains on Sibleys map) and at Sir Winston Churchill Park ( about at
the end of the word Alberta in the Sibley map) I am the most familiar with
them in the Swan Hills where I hear them each year when there to do a BBS
route. I cannot say which I hear the most but certainly both.
Unfortunately I am usually busy doing breeding bird surveys and butterfly
counts on the prairies and the western half of the province during the last
part of June so do not have records of the songs in the eastern part of the
province for sure of breeding birds.
Borror and Gunn have 5 recordings which vary in speed from 5 to 14
"chips"/second. Kevin Colvars is about 30, the five I have pulled out vary
from 6 to 21. The recordings on Lang Elliotts Disk vary from 5 - 9.
Borror and Gunn state that the pitch can be as high as 12 Hz and as low as
6.5 Hz. The faster songs seem to me to be higher pitched than the slower
ones but that just may be an artefact of the samples I have.
As far as I know do not have more than one subspecies of Blackpoll warbler.
I have always assumed that it was just normal variation in the song. There
are a lot more warblers who have more varied songs than this guy but guess I
should start noting more carefully what I hear
Barb Beck
Edmonton, Alberta, Canada
-----Original Message-----
From: NBHC ID-FRONTIERS Frontiers of Field Identification
Behalf Of Evan Obercian
Sent: May 28, 2002 11:24 AM
To:
Subject: [BIRDWG01] "Alaskan" Blackpolls
IDF,
In Alaska last spring I was struck by the rapidity of the song of Blackpolls
there. Conventional wisdom seems to hold that this song is heard only by
BLPWs in Alaska. As I was hearing it sung by birds seemingly on migration
(by habitat) in Anchorage, I thought it rather odd that this song is given
ONLY in Alaska, because I don't often hear warblers giving alternate songs
before they are on territory (but sometimes I do). If migrants in Alaska
give this song, why not migrants elsewhere bound for Alaska? Well, this
spring I have twice heard the "Alaskan" song type from migrant BLPWs in New
Jersey. That not only contradicts the rumors I've heard previously (that
this song is only given in Alaska) but also raises the question whether or
not I can assume these birds are bound for Alaska. Has anyone heard this
song outside of Alaska, either by migrants or by breeders?
I have not followed the vireo thread too closely. My only comment is that
the frequency-modulated BHVIs in the East that David Sibley refers to could
be at least partly the product of Yellow-throated Vireo influence. I have
occassionaly heard BHVI singing very YTVI-like song phrases and vice-versa.
regards,
Evan Obercian
NJ
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