[Tweeters] Union Bay Watch } Storm Passing

Dennis Paulson dennispaulson at comcast.net
Tue Apr 4 06:54:47 PDT 2017


Hello, tweets.

I’ve been working with Larry Hubbell on this since he asked me about the sexual dimorphism in Pileated Woodpecker eyes. I have seen the situation much as he has, supported by the photos I have of several of them. Birds of North America Online account says nothing of sexual dimorphism, nor does Peter Pyle, as Christine pointed out. But I would say both of those accounts show a lack of (presumably) doing anything more than just repeating what is in the literature before them. I doubt greatly if either Peter or the authors of the BNA account went out in the field to observe as many woodpeckers as they could to check on their eye color. Shocking as it may seem, this is probably the norm for guide-book writers. They can’t possibly go out and observe everything for themselves but have to depend on what people have stated before. Descriptions of birds in books are typically from museum specimens, in which plumage colors and patterns are evident, but they all have white cotton eyes. Some of them do have notes on iris color taken by those who prepare the specimens, but I’m starting to wonder if iris color may change after death in some birds, because notes on some museum specimens don’t go along with what we are observing.

Questioning authority is quite acceptable; we don’t know everything. In this case, Larry looked more closely at birds he followed from year to year and saw something interesting going on. It would be interesting to see how all the various field-guide authors have portrayed the eyes of this species.

I’m very surprised that anyone could have said or written anything that implied that PIWO don’t have yellow irises. All the photos of males I have and the ones I looked at online have bright yellow irises. One or more females that have been in my yard for nearly 10 years now has/have reddish irises. If I look closely at my best photos, with the eye in the sun, the reddish color seems to be caused by lots of tiny brown to reddish flecks in an otherwise yellow iris. In addition, this female, perhaps the only one for which I have good closeup photos, has a narrow dark ring around the iris that makes her pupil look larger than that of the male, but it’s just because of this ring. I’ll make my usual gratuitous statement that it’s too bad we can’t include an attachment or two to make our points!

Tweeters who are also photographers, especially those who watch birds of this species fledge and are able to photograph them for a while post-fledging, could contribute a lot to this ongoing question.

Dennis Paulson
Seattle

On Apr 3, 2017, at 11:06 PM, Hubbell <ldhubbell at comcast.net> wrote:


> Christine,

>

> Much of what I have seen agrees with Mr. Pyle. (I also have his books.) However, it seems to me there are some things which are unresolved. Like:

>

> a) Twice, I have seen gray eyes in young males just after fledging - which agrees with Mr. Pyle. However, I also have taken photos which clearly show one of the young male’s eyes turning yellow in August of the HY - which Mr. Pyle does not address. (I have not observed the same colors in young females. I do not know if this is a matter of happen stance e.g. the light has never been right or if young females have inherently darker eyes than young males e.g. possibly more brown.)

>

> b) My photos show Storm having red-eyes for ~4 years and Dennis Paulson has photos of mature female(s) with red eyes - which agrees with Mr. Pyle. However, thanks to a kind reader of my blog, I currently have a total of five photos, each showing a different female, with yellow irises - which Mr. Pyle does not mention.

>

> c) The female with Chip this year clearly has brown irises. I have followed her off and on for three months and taken dozens (possibly hundreds) of photos in good light. This makes her a new SY bird with iris coloring which agrees with Mr. Pyle. However many females in photos I see via Google have yellow irises - which Mr. Pyle does not address.

>

> d) Most males I see via Google have yellow irises and both of the adult males I have photographed around Union Bay, during the last five years, had yellow irises - which again Mr. Pyle does not mention.

>

> I am not finding fault with Mr. Pyle. I just think there is more to learn. I have not found any source which explains a development process or a relationship between the yellow and red colors. This why I am trying to gather more information.

>

> Yes, I would love to have a photo of the bird you were banding (along with the location and time) especially if we can see the iris color.

>

> Larry

>

> PS: I think there is one other assumption I am making which I should have stated up front. I believe the facial markings on pileated woodpeckers are unique. I realize feathers can move about in the wind or brush against a tree, etc. - however with enough photos of local birds and close observation I believe we can often identify individual pileated woodpeckers. The supercilium appears to be the major key to the process.

>

>

>

>> On Apr 3, 2017, at 7:57 PM, Christine Southwick <clsouth at u.washington.edu> wrote:

>>

>> Larry,

>>

>> According to the "Identification Guide to North American Birds", part 1, by Peter Pyle--(the book that all banders in North America use for aging, sexing, and band sizes):

>>

>> concerning Pileated Woodpeckers(PIWO)

>>

>> page 204

>>

>> Age--Juv (May-Sep)"...and iris probably gray-brown or brownish."

>> and

>> HY/SY "... and/or iris color probably grayer or browner (vs deep red in ASY/ATYs).."

>>

>> Note: Juv = nestling thru first year;

>>

>> HY = hatch year; SY = second year;

>>

>> ASY = after second year; ATY = after third year

>>

>> Based on this info of using eye coloring to help age a Pileated Woodpecker (PIWO), Storm could still be alive (with red eyes) since she still could have had brown eyes as a second year mother, with her eyes then changing to a deep red (Note: eye color can be very hard to determine unless being held in the hand.)

>>

>> She may, or may not, be alive--eye color in this case is not a valid eliminator. (If Storm had been shown with red eyes, and then there were only females with brown eyes, that would be a valid eliminator, provided there were good photos showing the eyes in good light (which you have).

>>

>> There is no indication that there is a sexual dimorphism of the eyes. Both males and females are assumed to follow the referenced color changes.

>>

>> I am not sure about the yellow eyes.

>> Some of your pictures, and in "The Owl and the Woodpecker" by Paul Bannick, on pages 44-45, both show females with apparently yellow eyes. Also the male nestling shown feeding on page 46 seems to have yellow eyes, but according to Pyle they should be gray with the angle of lighting playing tricks with our perceptions--or they really could be yellow, and Pyle somehow missed that in his many studies.

>>

>> That being said, PIWO mate for life, so I would focus on the male, Chip, and see if he is alone, has a mate, or is courting. If he appears to have a mate, with red eyes, it is possibly a grown-up mature Storm.

>>

>> Regards,

>>

>> Christine Southwick

>> clsouthwick at q.com

>> N Seattle/Shoreline

>>

>> P.S I have a picture showing a female PIWO being banded by myself and Don Norman, for anyone who is interested.

>>

>> On Sat, 1 Apr 2017, Hubbell wrote:

>>

>>> Date: Sat, 1 Apr 2017 15:44:20 -0700

>>> From: Hubbell <ldhubbell at comcast.net>

>>> To: tweeters at u.washington.edu

>>> Subject: [Tweeters] Union Bay Watch } Storm Passing

>>>

>>> Tweeters,

>>> This winter I have slowly come to the conclusion that Storm, our Union Bay female pileated woodpecker, is no longer with us. While digging through my

>>> pileated photos and studying the details I have once again spotted information which I had previous overlooked. Apparently, I have also reached the

>>> limit of our current knowledge about eye colors in female pileated woodpeckers. If you would like to help me expand my knowledge please read the

>>> following post:

>>>

>>> http://unionbaywatch.blogspot.com/2017/04/storm-passing.html

>>>

>>> Have a great day on Union Bay!

>>>

>>> Larry Hubbell

>>> ldhubbell at comcast dot net

>>>

>>

>> _______________________________________________

>> Tweeters mailing list

>> Tweeters at u.washington.edu

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>


-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net




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