Tweets:



Many observers have reported varied loons showing white flank patches at times,

especially when preening or when in feeding/diving mode. And then Red-throated

Loon can show white along the flank especially, and also tends to hold head/bill

upward. That said, the white flank on RT never seems to reach the fullest and

most symmetric expression as it does on Arctic. (And as we all know, RT does

not typically have dark plumage extending below the eye, RT giving off the "baby

face" impression, along with having a slimmer, paler bill than Pacific/Arctic).


This is all timely, because I just posted an Arctic Loon report from

Port Angeles, seen on the Jan. 2 CBC, to Ebird:

https://ebird.org/checklist/S78633096. No photo was possible, but

most details are given in writing there.


The slightly heavier bill & overall length, uptilted head/bill posture,

and side-profile silhouette of Arctic--what could be called overall

"presence" (or "gizz" in past parlance)--differ from Pacific Loon.

Brad is correct here in noting similarity to Common Loon. Overall length

of Arctic is about midway between Common and Pacific, but often comes

off as more like Common in the field, and Arctic seems to sit a bit lower in

the water than Pacific sometimes, likely reflecting a slightly heavier/

longer bird. The uptilted head/bill and side-profile

silhouette (for overall length, bill, head shape and back) are good

field-marks for Arctic, but a uniform, and full-length, white flank patch has

historically been considered important.


Back seems less neatly uniform and rounded than on Pacific, still again reminiscent

of Common Loon.


All of the above were evident with the Port Angeles bird, which was

at rest (and at side profile the entire time). Although I did not see the

Port Angeles bird fly off, Arctic seems a little heavier in flight than Pacific also.


My core experience comes from nearly 30 years of Russian Far East

visitation, including at-sea time; both Pacific and Arctic Loons are

common at times, such as migrants along s.e. Kamchatka, for

example.



Scott Atkinson

Lake Stevens



___________________________________________________________________________

Nice comments by Brad Waggoner. And clearly not to discourage anyone from

looking for Arctic Loons. They are indeed rare and all the more reason to

look for them. Always best to post to Tweeters if you have found a

'suspect'.

Take a look and decide what you think, based upon Brad's comments, about

the ID of these two Oregon loons, which I photographed over a period of

many years. (P.S. There was nothing 'highly' unusual about the posture of

either one.) Comments online or offline welcomed. To be continued.

https://www.flickr.com/photos/...<https://www.flickr.com/photos/159695762 at N07/?>

Bob O'Brien Portland




Hi all,



It seems every winter there are a handful of reports of an Arctic Loon and "white flanks" are provided as the reasoning for the identification. The presence of white flanks is really not the identifying feature of an Arctic Loon. And all of our common expected species of loons can exhibit this feature to some degree depending on the individual bird depending on posture or behavior. The specific key feature to send one down the path of a potential Arctic Loon identification is an enlarged white "bubble" or oval area in the rear area of those white flanks. Then there are some subtle features such as a somewhat blocky head and larger bill than a Pacific Loon that will be of additional help. I think actually an Arctic Loon can tend somewhat more suggestive of a Common Loon than a Pacific Loon.



There are only a handful of WBRC approved records of Arctic Loon so it truly is a rare bird in Washington.



Good birding and Happy New Year!



Brad Waggoner


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