No subject
Sat Jun 30 23:22:37 PDT 2007
(conservatively 500+), take it from me...there's a lot of variation in =
the plumage of the males. That being said, it's pretty likely that the =
"blacker" backed birds are older males. Also, having captured and =
banded a lot of Lesser Goldfinches, I have recaptured very few (about 2 =
were recaptured after along the Applegate River - Josephine Co - in =
following years, where they were likely nesting birds). The few I have =
recaptured at TNC Whetstone were perhaps a month or so between =
recaptures during the same year. You just don't recapture very many at.
Bottom line with them is that they are loosely loyal to nesting =
locations (mostly riparian), but otherwise are wanders in search of food =
sources (go where the food is). The distance they wander is (to me at =
least) in not well known - they just don't wander back to certain =
capture locations very much it appears.
Dennis=20
Concerning Lesser Goldfinches with black backs:
I think that we need to keep in mind that this a a species which has =
not been well studied in comparison to many other species. Dark-backed =
males apparently do occasionally appear in males of the race of Lesser =
Goldfinch found in western Oregon. In most instances, these individuals =
will still show a green tinge around the nape and not be so solidly =
glossy black as the birds found in Mexico and southern Texas. Both forms =
occur with greater frequency in the race found in the eastern portion of =
this species range (Colorado to Texas). More black-backed forms occurr =
as one proceeds from north to south. This has led some authors to assume =
that this is a polymorphic species with both color phases occurring in =
the population, but not everyone goes along with this idea. I don't =
believe that the genetics of this species has been closely examined so =
it is hard to know if we are seeing individuals that differ based =
strictly on genetics or if the variability is caused by other factors.
In any event, I would suspect that the birds being seen and reported =
here, fall with the range of known variability for our race of Lesser =
Goldfinch (Carduelis pasltria herperophilus). It seems unlikely that =
southern birds have wandered into Oregon, especially at this time of =
year. Consider also, that this species is not considered migratory. Some =
individuals do wander, more so in northern birds than southern =
populations, and there is some altitudinal movements known that are =
associated with the seasons. But no long distance movements have been =
traced. This remains a species about which we still have much to learn.
Dan Gleason
-------------
Dan Gleason
dan-gleason at comcast.net
541 345-0450
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<META http-equiv=3DContent-Type content=3D"text/html; =
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<META content=3D"MSHTML 6.00.6000.16481" name=3DGENERATOR>
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<DIV><FONT face=3DArial size=3D2>Lesser Goldfinch watchers,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>From a fellow that has captured a lot =
of Lesser=20
Goldfinches (conservatively 500+), take it from me...there's a lot of =
variation=20
in the plumage of the males. That being said, it's pretty likely =
that the=20
"blacker" backed birds are older males. Also, having captured =
and=20
banded a lot of Lesser Goldfinches, I have recaptured very =
few (about 2=20
were recaptured after along the Applegate River - Josephine Co =
- in following years, where they were likely nesting birds). =
The few=20
I have recaptured at TNC Whetstone were perhaps a month or =
so between=20
recaptures during the same year. You just don't recapture very =
many=20
at.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Bottom line with them is that they =
are loosely=20
loyal to nesting locations (mostly riparian), but =
otherwise are=20
wanders in search of food sources (go where the food is). The =
distance=20
they wander is (to me at least) in not well known - they just don't =
wander=20
back to certain capture locations very much it =
appears.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Dennis</FONT> </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><BR></DIV>Concerning Lesser Goldfinches =
with black=20
backs:
<DIV><BR class=3Dkhtml-block-placeholder></DIV>
<DIV>I think that we need to keep in mind that this a a species which =
has not=20
been well studied in comparison to many other species. Dark-backed =
males=20
apparently do occasionally appear in males of the race of Lesser =
Goldfinch=20
found in western Oregon. In most instances, these individuals will =
still show=20
a green tinge around the nape and not be so solidly glossy black as =
the birds=20
found in Mexico and southern Texas. Both forms occur with greater =
frequency in=20
the race found in the eastern portion of this species range (Colorado =
to=20
Texas). More black-backed forms occurr as one proceeds from north to =
south.=20
This has led some authors to assume that this is a polymorphic species =
with=20
both color phases occurring in the population, but not everyone goes =
along=20
with this idea. I don't believe that the genetics of this species has =
been=20
closely examined so it is hard to know if we are seeing individuals =
that=20
differ based strictly on genetics or if the variability is caused by =
other=20
factors.</DIV>
<DIV><BR class=3Dkhtml-block-placeholder></DIV>
<DIV>In any event, I would suspect that the birds being seen and =
reported=20
here, fall with the range of known variability for our race of Lesser=20
Goldfinch (Carduelis pasltria herperophilus). It seems unlikely that =
southern=20
birds have wandered into Oregon, especially at this time of year. =
Consider=20
also, that this species is not considered migratory. Some individuals =
do=20
wander, more so in northern birds than southern populations, and there =
is some=20
altitudinal movements known that are associated with the seasons. But =
no long=20
distance movements have been traced. This remains a species about =
which we=20
still have much to learn.</DIV>
<DIV><BR class=3Dkhtml-block-placeholder></DIV>
<DIV>Dan Gleason<BR>
<DIV><SPAN class=3DApple-style-span=20
style=3D"WORD-SPACING: 0px; FONT: 12px Verdana; TEXT-TRANSFORM: none; =
COLOR: rgb(0,0,0); TEXT-INDENT: 0px; WHITE-SPACE: normal; =
LETTER-SPACING: normal; BORDER-COLLAPSE: separate; border-spacing: 0px =
0px; -khtml-text-decorations-in-effect: none; -apple-text-size-adjust: =
auto; orphans: 2; widows: 2"><SPAN=20
class=3DApple-style-span=20
style=3D"WORD-SPACING: 0px; FONT: 12px Verdana; TEXT-TRANSFORM: none; =
COLOR: rgb(0,0,0); TEXT-INDENT: 0px; WHITE-SPACE: normal; =
LETTER-SPACING: normal; BORDER-COLLAPSE: separate; border-spacing: 0px =
0px; -khtml-text-decorations-in-effect: none; -apple-text-size-adjust: =
auto; orphans: 2; widows: 2"><SPAN=20
class=3DApple-style-span=20
style=3D"WORD-SPACING: 0px; FONT: 12px Verdana; TEXT-TRANSFORM: none; =
COLOR: rgb(0,0,0); TEXT-INDENT: 0px; WHITE-SPACE: normal; =
LETTER-SPACING: normal; BORDER-COLLAPSE: separate; border-spacing: 0px =
0px; -khtml-text-decorations-in-effect: none; -apple-text-size-adjust: =
auto; orphans: 2; widows: 2">
<DIV>-------------</DIV>
<DIV>Dan Gleason</DIV>
<DIV><A=20
href=3D"mailto:dan-gleason at comcast.net">dan-gleason at comcast.net</A></DIV>=
<DIV>541=20
345-0450</DIV></SPAN></SPAN></SPAN></DIV></DIV></BLOCKQUOTE></BODY></HTML=
>
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