[EBB Sightings] Some Swamp Sparrow info

--Apple-Mail-7-674130072
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=WINDOWS-1252;
	delsp=yes;
	format=flowed

Akira and others who might be interested,

You can also find specific information about molt, sex, age, etc. in =20
Peter Pyle's, et al, "Identification Guide to North American Birds" =20
1997, available from Slate Creek Press in Bolinas. This is the North =20
American banders' "bible". It notes that there are 3 subspecies of =20
Swamp Sparrow with Melospiza georgiana ericrypta being the one that =20
winters in California. In the descriptions, it notes that in alternate =20=

(breeding) plumage, this ssp. has a medium-pale rufous crown, with =20
little or no black streaking by sex. Under the section describing =20
plumage differences by sex, it notes that the crown shows the only =20
plumage differences by sex; otherwise, banders need to look at breeding =20=

condition. Since they don't breed here and since M.g. ericrypta doesn't =20=

show the crown streaking difference, sexing Swamp Sparrows seen in =20
California may be pointless.

Another good reference is the Birds of North America collection of =20
monographs on all NA species. You should be able to find a set at a =20
library, a college library, or a bird-affiliated organizations (e.g., =20=

the Santa Clara Valley Audubon Society has a set in their library). =20
Look for:

BNA No. 279
Mowbray, T. B. 1997. Swamp Sparrow (Melospiza georgiana). In The Birds =20=

of North America, No. 279 (A. Poole and F. Gill, eds.). The Academy of =20=

Natural Sciences, Philadelphia, PA, and The American Ornithologists=92 =20=

Union, Washington, D.C.

Or, you can subscribe to the online set at Cornell's website ($40/yr) =20=

and see the species account by Thomas B. Mowbray. (four of Russell =20
Greenberg's papers appear in its bibliography). One benefit of the =20
online version over the printed version is that you can see footage and =20=

listen to sound clips with the former. =20

Les
---
Les Chibana
BirdNUTZ(tm) - Ornigasmic Birding
Palo Alto Baylands Birding Classes
em 
web 
ph 650-949-4335
fx 650-949-4137
snailmail: SR2 Box 335, La Honda CA 94020

On Mar 4, 2005, at 10:54 AM, Akira So wrote:

> Stephen Long wrote:
> > ...
> > The bird is working hard on its molt into alternate plumage;
> > it still has a good deal of buff in the gray cheek patches,
> > and the crown hasn't yet attained its unstreaked reddish color,
> > but the scapulars are broadly tipped with white.  This was a
> > county bird for me.
> I have been a little confused about this Swamp Sparrow in Livermore, =20=

> in particular about its plumage, plumage differences between the sexes =
=20
> (if any), and molting as it relates to it.
> Stephen's comments finally prompted me to do a very cursory "research" =
=20
> on the web last night, and I came across the following two published =20=

> papers on Swamp Sparrow, both written by Russell Greenberg, that =20
> contain some interesting information on Swamp Sparrows, including =20
> answers to my own questions. I'd like to mention them here in case =20
> anyone else find them useful:
> [1] Greenberg, R. 1990. Adaptations to tidal marshes in breeding =20
> populations of the swamp sparrow. The Condor 92:393-404
> http://nationalzoo.si.edu/ConservationAndScience/MigratoryBirds/=20
> About_us/Greenberg/Papers/greenberg_swsp_adaptations.pdf
> [2] Greenberg, R. 1988. Seasonal plumage dimorphism in the swamp =20
> sparrow. J. Field Ornithol., 59(2):149-154
> http://elibrary.unm.edu/sora/JFO/v059n02/p0149-p0154.pdf
> Basically, my personal confusion centered around the issue of telling =20=

> the sexes apart in the field (based on plumages), and if the bright =20=

> rusty crown patch in adult breeding plumage had anything to do with =20=

> it.
> For example, "A Guide to the Identification and Natural History of The =
=20
> Sparrows of the United States and Canada" (Rising and Beadle, 1996) =20=

> says "sexes similar in coloration" in the Swamp Sparrow section. This =20=

> seems to suggest trying to guess a sex based on plumage might be =20
> futile.
> But "The Sibley Guide to Birds" (David Allen Sibley, 1st ed. 2nd =20
> printing, 2000) depicts a male and a female breeding adult separately, =
=20
> although it's not clear to me exactly which differences depicted there =
=20
> are meant to be due to sex and which are just individual variations. =20=

> (It shows a bright rusty crown on male and darker streaked crown for =20=

> female, and it also includes a caption "clean gray" pointing to the =20=

> male's nape area, among other more subtle differences.)
> On the topic of molting pattern in sparrows in general, Rising gives =20=

> the following information: "The breeding (or alternate) plumage and =20=

> winter (or basic) plumage are similar in most species, and the =20
> prebasic molt, which takes place after breeding, though variable in =20=

> the group, is generally complete. The spring, prealternate, molt is =20=

> absent or incomplete. In dimorphic species, much of the brightness of =20=

> the male breeding plumage is acquired through wear."
> (I was aware about the wear creating breeding adult plumages in, for =20=

> example, Snow Bunting. But, in the case of Swamp Sparrow, is the =20
> spring molt absent or incomplete? Does it acquire the rusty crown =20
> through wear - didn't seem likely - or through an incomplete molt? =20
> These were some of my questions.)
> In short, the above two papers seem to suggest the following:
> 1) Swamp Sparrow goes thorough an incomplete spring molt mostly in the =
=20
> head, nape, and throat feathers. (But not the flight feathers, tail =20=

> feathers, etc.)
> 2) Swamp Sparrow exhibits a rather unusual (for sparrow) _seasonal_ =20=

> sexual dimorphism in its crown coloration, created by the spring =20
> molting process. (The sex differences are strong in the =20
> breeding/alternate plumages, much less so in the winter/basic =20
> plumages)
> 3) With regard to the Livermore Swamp Sparrow (a 1st winter bird), it =20=

> appears to be in the process of this spring molt as Stephen mentioned. =
=20
> (For example the nape area looks pretty gray already, not buffy. But =20=

> the face is still not quite gray. Crown is dark brown with no rusty.)
> 4) An unstreaked bright rusty crown patch often mentioned in various =20=

> field guides, etc. for the breeding adult plumages may or may not =20
> clearly emerge in this particular sparrow, depending on, in large =20
> part, the sex. (Due to the aforementioned seasonal sexual dimorphism, =20=

> it would be more likely if it turns out to be a male; it would be less =
=20
> likely if it turns out to be a female.)
> Lastly, here are some relevant excerpts from these two papers:
> - "Swamp Sparrows complete a molt in the autumn (late August-October; =20=

> Dwight 1900, pers. observ.) replacing most of the contour feathers in =20=

> juveniles and, additionally, the flight and tail feathers in adults. A =
=20
> prenuptial molt involves primarily the head, nape, and throat feathers =
=20
> (pers. observ. of captive Swamp Sparrows). Therefore, summer specimens =
=20
> have relatively worn body, wing, and tail feathers, yet have =20
> relatively fresh plumage over the head region." [1]
> - "Swamp Sparrows (Melospiza georgiana) have crowns that range from =20=

> dull brown to bright rust. Although most descriptions state correctly =20=

> that Swamp Sparrows in the non-breeding season generally have duller =20=

> crowns than in the breeding season, within seasons the variation in =20=

> crown color has been almost universally ascribed to differences in age =
=20
> ... Field identification guides have often attributed most variation =20=

> in crown color to age." [2]
> - "Breeding season specimens show strong dimorphism (Fig. 1): 85% of =20=

> males and only 10% of the females had completely rusty crowns (crown =20=

> class 4)." [2]
> - "Swamp Sparrows show significant dimorphism in crown color in all =20=

> plumages, but only in the breeding season is the overlap in the =20
> distribution of the two sexes sufficiently small to be helpful in the =20=

> determining the sex of an individual. This dimorphism results =20
> primarily from males acquiring complete rusty caps." [2]
> Hope this helps. Good birding!
> -Akira
> Pleasanton, CA
> (Alameda County)=

--Apple-Mail-7-674130072
Content-Transfer-Encoding: quoted-printable
Content-Type: text/enriched;
	charset=WINDOWS-1252

Akira and others who might be interested,


You can also find specific information about molt, sex, age, etc. in
Peter Pyle's, et al, "Identification Guide to North American Birds"
1997, available from Slate Creek Press in Bolinas. This is the North
American banders' "bible". It notes that there are 3 subspecies of
Swamp Sparrow with Melospiza georgiana ericrypta being the one that
winters in California. In the descriptions, it notes that in alternate
(breeding) plumage, this ssp. has a medium-pale rufous crown, with
little or no black streaking by sex. Under the section describing
plumage differences by sex, it notes that the crown shows the only
plumage differences by sex; otherwise, banders need to look at
breeding condition. Since they don't breed here and since M.g.
ericrypta doesn't show the crown streaking difference, sexing Swamp
Sparrows seen in California may be pointless.


Another good reference is the Birds of North America collection of
monographs on all NA species. You should be able to find a set at a
library, a college library, or a bird-affiliated organizations (e.g.,
the Santa Clara Valley Audubon Society has a set in their library).
Look for:


=
ad-smaller>BNA
No. 279

Mowbray, T. B. 1997. Swamp Sparrow
(Melospiza
georgiana).
=
maller>
The Birds of North America, No. 279 (A. Poole and F. Gill, eds.). The
Academy of Natural Sciences, Philadelphia, PA, and The American
Ornithologists=92 Union, Washington, =
D.C.


Or, you can subscribe to the online set at Cornell's website ($40/yr)
and see the species account by Thomas B. Mowbray. (four of Russell
Greenberg's papers appear in its bibliography). One benefit of the
online version over the printed version is that you can see footage
and listen to sound clips with the former.



---

Les Chibana

BirdNUTZ(tm) - Ornigasmic Birding

Palo Alto Baylands Birding Classes

em <

web <

ph 650-949-4335

fx 650-949-4137

snailmail: SR2 Box 335, La Honda CA 94020


On Mar 4, 2005, at 10:54 AM, Akira So wrote:



> ...

> The bird is working hard on its molt into alternate plumage;

> it still has a good deal of buff in the gray cheek patches,

> and the crown hasn't yet attained its unstreaked reddish color,

> but the scapulars are broadly tipped with white.  This was a

> county bird for me.


I have been a little confused about this Swamp Sparrow in Livermore,
in particular about its plumage, plumage differences between the sexes
(if any), and molting as it relates to it.


Stephen's comments finally prompted me to do a very cursory "research"
on the web last night, and I came across the following two published
papers on Swamp Sparrow, both written by Russell Greenberg, that
contain some interesting information on Swamp Sparrows, including
answers to my own questions. I'd like to mention them here in case
anyone else find them useful:


[1] Greenberg, R. 1990. Adaptations to tidal marshes in breeding
populations of the swamp sparrow. The Condor 92:393-404

=
http://nationalzoo.si.edu/ConservationAndScience/MigratoryBirds/About_us/G=
reenberg/Papers/greenberg_swsp_adaptations.pdf


[2] Greenberg, R. 1988. Seasonal plumage dimorphism in the swamp
sparrow. J. Field Ornithol., 59(2):149-154

http://elibrary.unm.edu/sora/JFO/v059n02/p0149-p0154.pdf


Basically, my personal confusion centered around the issue of telling
the sexes apart in the field (based on plumages), and if the bright
rusty crown patch in adult breeding plumage had anything to do with it.


For example, "A Guide to the Identification and Natural History of The
Sparrows of the United States and Canada" (Rising and Beadle, 1996)
says "sexes similar in coloration" in the Swamp Sparrow section. This
seems to suggest trying to guess a sex based on plumage might be
futile.


But "The Sibley Guide to Birds" (David Allen Sibley, 1st ed. 2nd
printing, 2000) depicts a male and a female breeding adult separately,
although it's not clear to me exactly which differences depicted there
are meant to be due to sex and which are just individual variations.
(It shows a bright rusty crown on male and darker streaked crown for
female, and it also includes a caption "clean gray" pointing to the
male's nape area, among other more subtle differences.)


On the topic of molting pattern in sparrows in general, Rising gives
the following information: "The breeding (or alternate) plumage and
winter (or basic) plumage are similar in most species, and the
prebasic molt, which takes place after breeding, though variable in
the group, is generally complete. The spring, prealternate, molt is
absent or incomplete. In dimorphic species, much of the brightness of
the male breeding plumage is acquired through wear."


(I was aware about the wear creating breeding adult plumages in, for
example, Snow Bunting. But, in the case of Swamp Sparrow, is the
spring molt absent or incomplete? Does it acquire the rusty crown
through wear - didn't seem likely - or through an incomplete molt?
These were some of my questions.)


In short, the above two papers seem to suggest the following:


1) Swamp Sparrow goes thorough an incomplete spring molt mostly in the
head, nape, and throat feathers. (But not the flight feathers, tail
feathers, etc.)


2) Swamp Sparrow exhibits a rather unusual (for sparrow) _seasonal_
sexual dimorphism in its crown coloration, created by the spring
molting process. (The sex differences are strong in the
breeding/alternate plumages, much less so in the winter/basic plumages)


3) With regard to the Livermore Swamp Sparrow (a 1st winter bird), it
appears to be in the process of this spring molt as Stephen mentioned.
(For example the nape area looks pretty gray already, not buffy. But
the face is still not quite gray. Crown is dark brown with no rusty.)


4) An unstreaked bright rusty crown patch often mentioned in various
field guides, etc. for the breeding adult plumages may or may not
clearly emerge in this particular sparrow, depending on, in large
part, the sex. (Due to the aforementioned seasonal sexual dimorphism,
it would be more likely if it turns out to be a male; it would be less
likely if it turns out to be a female.)


Lastly, here are some relevant excerpts from these two papers:


- "Swamp Sparrows complete a molt in the autumn (late August-October;
Dwight 1900, pers. observ.) replacing most of the contour feathers in
juveniles and, additionally, the flight and tail feathers in adults. A
prenuptial molt involves primarily the head, nape, and throat feathers
(pers. observ. of captive Swamp Sparrows). Therefore, summer specimens
have relatively worn body, wing, and tail feathers, yet have
relatively fresh plumage over the head region." [1]


- "Swamp Sparrows (Melospiza georgiana) have crowns that range from
dull brown to bright rust. Although most descriptions state correctly
that Swamp Sparrows in the non-breeding season generally have duller
crowns than in the breeding season, within seasons the variation in
crown color has been almost universally ascribed to differences in age
... Field identification guides have often attributed most variation
in crown color to age." [2]


- "Breeding season specimens show strong dimorphism (Fig. 1): 85% of
males and only 10% of the females had completely rusty crowns (crown
class 4)." [2]


- "Swamp Sparrows show significant dimorphism in crown color in all
plumages, but only in the breeding season is the overlap in the
distribution of the two sexes sufficiently small to be helpful in the
determining the sex of an individual. This dimorphism results
primarily from males acquiring complete rusty caps." [2]



Hope this helps. Good birding!


-Akira

Pleasanton, CA

(Alameda County)=

--Apple-Mail-7-674130072--