Thanks for everyone's replies on this different quiz.... I thought I would
share this "challenge" because as I was uploading my photos to eBird I
noticed these two geese and thought, "Wow, they look a lot alike. Are they
the same?" So, I had to recall my photographing experience and verified
what I remembered by looking at the photos. I also thought I would share
the exercise because discerning individuals is not something we do very
often. It really gives us practice in searching for characteristics---in
this case on a very common and observable bird---that on other species are
crucial for identification and/or aging. I'm speaking of things like head
shape on scaup and goldeneye, bill shape on Brewer's and Rusty blackbirds,
worn feathers for aging buntings and other passerines, different
colored/shaded feathers for aging shorebirds or discerning molt timing of
gulls. We can get an introduction to these things on local park pond Canada
Geese!
They are indeed two different birds. All Barbara's cautions are real and
well-deserved (I'm impressed with the skills you gain as a carver!!!).
Wayne hit on most of the points I noticed and a couple others. Even with
the angle that Barbara specified, I think the 801 bird is a longer and
larger bird, while 811 is a shorter, stockier bird overall. I have prepared
two images bringing out many, but not all detailed points of difference.
The photos were taken within a few seconds of each other, with no feather
fluffing in between. These two photos are consecutive in my photostream, so
you can just tap from one to the next, back and forth (you can also click
on the photo to enlarge somewhat)....
https://www.flickr.com/photos/matthewghunter/25006578293 ;(this is what
Wayne identified as 801)
https://www.flickr.com/photos/matthewghunter/25265725059 ;(this is what
Wayne identified as 811)
Best,
Matt Hunter
Melrose, OR
West-Central DougCo
On Mon, Mar 7, 2016 at 8:45 PM, <whoffman@xxxxxxxx> wrote:
Hi -
You have 3 photos with Canada Geese in poses suitable for comparison,
labeled ML25277341, ML25277801, and ML25277811. For simplicity I'll refer
to them by the last 3 digits, 341, 801, and 811. I am guessing you meant
us to compare 801 with 811 because 341 is included under the Snow Goose
heading, and also contains that bird. However, I will compare all three.
341 looks different to me. 341 shows a whiter chest, contrasting more
with the brownish flanks. The direction and lighting are different, but I
doubt that would fully account for the differences. The pattern of
"stacking" of the rows of upper wing coverts is also quite different. In
341 I see rows of coverts stacked neatly like rows of shingles. 801 and
811 show fewer rows, varying more in width, and give the appearance of
fewer feathers in each row, and more variation in feather size.
Now to compare 801 and 811: These are more similar, but I think they are
different birds as well. First, the appearance of the primary tips lying
against the tail is quite different. The tail is elevated in 811, which
could re-arrange the primaries, but I on't think that is the whole
explanation. There are also a bunch of differences in the wing coverts. I
recognize that with one vigorous shake, a goose could re-arrange these
feathers quite a bit, but the patterns seem too different to be accounted
for that way. Working from posterior forward, the posterior-most row looks
squared-off in outline on 801, and more rounded on 811. On 801 I see this
outer row, a second row, and then a row that appear to be smaller feathers
more tightly overlapped. On 811 the smaller, tightly overlapped row is the
4th one in. There are other detail differences in the coverts further
forward. A few feathers on each look darker than their surroundings, which
I suspect were more recently replaced. These seem to be in different
locations on the two birds. Moving forward, the white cheeks seem slightly
different in outline, with a slight posterior bulge on 801 that seems
absent on 811. The margin between the facial feathering and the bill seems
slightly different in the two, with the feathering extending slightly
farther forward on 811. The "points" on the bill seem to reach a bit
closer to the eye on 811. Finally, 801 appears to have a slightly more
prominent nail on the bill, and 811 appears to have a bump under the end of
the mandible.
Anyway, that's my stab at it.
Wayne
------------------------------
*From: *"Matthew G Hunter" <matthewghunter@xxxxxxxxx>
*To: *"obol" <obol@xxxxxxxxxxxxx>
*Sent: *Monday, March 7, 2016 7:02:05 PM
*Subject: *[obol] A Different Kind of Bird Quiz
If you go to this checklist and page down to the first two Canada Goose
photos:
http://ebird.org/ebird/view/checklist?subID=S27952911
Are these photos of the same bird? Are they photos of two different birds?
What differences can you see? Are they real differences, or due to bird
angle or position?
:-) What do you see?
Share your thoughts with the rest of us.
Matt Hunter
Melrose, OR